Submitted Successfully!
To reward your contribution, here is a gift for you: A free trial for our video production service.
Thank you for your contribution! You can also upload a video entry or images related to this topic.
Version Summary Created by Modification Content Size Created at Operation
1
Jorge E. Contreras
 + 3280 word(s) 3280 2021-05-17 08:02:25 |
2 format correct
Vivi Li
Meta information modification 3280 2021-05-25 08:06:21 |

Video Upload Options

Do you have a full video?
Send video materials Upload full video

Confirm

Are you sure to Delete?
Yes No
Cite
If you have any further questions, please contact Encyclopedia Editorial Office.
Contreras, J.E. Pannexin-1 Channels and Neuroinflammation. Encyclopedia. Available online: https://encyclopedia.pub/entry/10015 (accessed on 23 April 2024).
Contreras JE. Pannexin-1 Channels and Neuroinflammation. Encyclopedia. Available at: https://encyclopedia.pub/entry/10015. Accessed April 23, 2024.
Contreras, Jorge E.. "Pannexin-1 Channels and Neuroinflammation" Encyclopedia, https://encyclopedia.pub/entry/10015 (accessed April 23, 2024).
Contreras, J.E. (2021, May 24). Pannexin-1 Channels and Neuroinflammation. In Encyclopedia. https://encyclopedia.pub/entry/10015
Contreras, Jorge E.. "Pannexin-1 Channels and Neuroinflammation." Encyclopedia. Web. 24 May, 2021.
Pannexin-1 Channels and Neuroinflammation
Edit
This entry is adapted from the peer-reviewed paper 10.3390/ijms22105189

Neuroinflammation is a major component of central nervous system (CNS) injuries and neurological diseases, including Alzheimer’s disease, multiple sclerosis, neuropathic pain, and brain trauma. The activation of innate immune cells at the damage site causes the release of pro-inflammatory cytokines and chemokines, which alter the functionality of nearby tissues and might mediate the recruitment of leukocytes to the injury site. If this process persists or is exacerbated, it prevents the adequate resolution of the inflammation, and ultimately enhances secondary damage. Adenosine 5′ triphosphate (ATP) is among the molecules released that trigger an inflammatory response, and it serves as a chemotactic and endogenous danger signal. Extracellular ATP activates multiple purinergic receptors (P2X and P2Y) that have been shown to promote neuroinflammation in a variety of CNS diseases. Recent studies have shown that Pannexin-1 (Panx1) channels are the principal conduits of ATP release from dying cells and innate immune cells in the brain.

neuroinflammation Pannexin-1 hemichannel brain injury

1. Background

Over the past few decades, rapid advancements in medical research have led to increasing life expectancy, but the socioeconomic impact of diseases associated with aging, including neurodegenerative diseases, traumatic brain injury (TBI), and stroke, is increasing considerably [1][2][3]. While the pathological mechanisms of the aforementioned diseases are not completely understood, it is becoming clear that neuroinflammation is a shared pathophysiological feature [4][5][6][7][8]. In general, inflammation is an adaptive immune response initiated by noxious stimuli such as infection or tissue injury [9]. While a successful inflammatory response results in wound healing and elimination of invading pathogens, persistent and uncontrolled inflammation may contribute to negative outcomes, including the exacerbation of cell death and tissue damage [10]. The native immune response triggered by brain pathologies can also be beneficial or detrimental depending on the timing of the resolution for the inflammatory response. The identification and understanding of the molecular mediators responsible for neuroinflammation may contribute to the development of novel therapeutic targets for numerous neurological diseases. Here, we focus on the role of Pannexin-1 (Panx1) channels as promoters of inflammation in brain pathologies. Panx1 proteins are expressed in most brain cells, including neurons and glia, from early developmental stages to throughout adulthood [11][12][13][14][15][16][17][18][19][20][21]. They work as pore conduits for adenosine triphosphate (ATP) release, which consequently activates purinergic signaling via P2X and P2Y receptors [22]. Activation of Panx1 channels has been implicated in chemotaxis [23], leukocyte infiltration [24], inflammasome activation [25] and pyroptosis [26], and neurophatic pain [27][28] (Figure 1).
Ijms 22 05189 g001 550
Figure 1. Diverse function of Panx1 channels in neuroinflammation. In the brain, Panx1 channels are expressed in neurons, astrocytes, and microglia. Upon tissue injury, Panx1 channels are activated and become permeable to ATP, which acts as a central damage-associated molecular pattern (DAMP) via P2X and P2Y receptors. In consequence, extracellular ATP initiates a complex cascade of inflammatory response, including immune cell infiltration, inflammasome activation, glia proliferation, and scar formation.

2. Pannexin-1 (Panx1) Channels

Pannexin channels are a group of transmembrane channel proteins responsible for autocrine/paracrine communication. They were discovered as proteins homologous to innexins found in invertebrates, which form gap junction channels. There are three gene family members of pannexin channels expressed in mammals, namely Panx1, Panx2 and Panx3 [11]. Panx1 is ubiquitously expressed in various organs and tissues, including the brain, spinal cord, eye, heart, and thyroid [11]. Panx2 and Panx3 expression are more restricted to certain tissues; for instance, Panx2 is highly expressed in the brain and Panx3 is mainly expressed in skin and bone Based on the structural properties of these channels, they allow movements of ions, small metabolites, and secondary messengers up to 1 kDa in size [29]. The pannexin channels have been found to play important roles in normal development and various physiological functions, including skin and bone development, synaptic plasticity, and blood vessel regulation [22][30][31][32][33][34]. Of all pannexins, Panx1 proteins are the most abundantly expressed in the brain, and comprising various cell-types, such as microglia, astrocytes, oligodendrocytes, and neurons [11][12][13][14][15][16][17][18][19][20][21]. An important function of Panx1 channels is associated with calcium signaling via ATP release and the activation of P2X and P2Y receptors [35]. It has been shown that the binding of ATP to G-coupled P2Y receptors will activate PLC and IP3 pathways, which release calcium from intracellular store (ER) [35]. It has also been proposed that an increase of calcium concentration from intracellular sources further activates Panx1 channels mediating an ATP-dependent ATP release, which further propagates calcium signaling to neighboring cells [22]. Moreover, Panx1 channels have been shown to form a complex with P2X7 purinergic receptors [36]; the latter are known to be molecular players that amplify CNS damage and neuroinflammation in various brain pathologies [37]. Various other plasma receptors or proteins involved brain pathologies, including NMDA receptors or caspases, have been linked to Panx1 channel activation (Figure 2). Below we described some of them in further detailed.
Ijms 22 05189 g002 550
Figure 2. Current understanding of Panx1 channel activation in neuroinflammation. Upon cerebral ischemia, NMDA receptors activate Panx1 channels via phosphorylation by Src Kinase. Various infections and injuries can activate P2X7 and TLR receptors, which have been shown to activate Panx1 channels.

3. Pannexin-1 Channels in Neuroinflammation

Panx1 channel activation is broadly associated with pathological processes including cancer [38][39], ischemia [30][40], platelet activation [41], seizure [42], immune cell migration [31], and HIV viral replication [43]. Freeman and colleagues showed that reducing Panx1 protein levels with shRNA, or blockade of Panx1 channel activity using carbenoxolone or probenecid, significantly reduced the level of cell growth and cell migration of A375-P and A375-MA2 melanoma cell lines [38]. Furthermore, Panx1 channel activation is implicated in seizure activity in humans and animal models of epilepsy [42][44]. Using post-operative human brain samples, Dossi and her colleagues demonstrated that pharmacological inhibition of Panx1 channel with probenecid and mefloquine blocked ictal discharges. In addition, the authors showed that mice harboring genetic deletion of Panx1 were resistant to kainic acid-induced seizures [42][45]. Panx1 channels have also been shown to play an important role in CD4+ T lymphocytes during the course of infection by HIV-1. By using fluorescent techniques, it was shown that HIV isolates (R5 and X4) induced transient-early and sustained-later opening of Panx1 channels, which was dependent on HIV binding to the CD4/CCR5/CXCR4 complex [43].
Since many, if not all, CNS injuries and diseases involve a certain degree of neuroinflammation [46], it is likely that the therapeutic modulation of the neuroinflammatory response may serve as a potential approach for treating brain injuries and neurological diseases. Indeed, many novel therapeutic targets for neurodegenerative diseases that were traditionally thought to be neuronal in nature, including Alzheimer’s disease (AD), Parkinson’s disease (PD), and amyotrophic lateral sclerosis (ALS), modulate the immune response of astrocytes and microglia [47][48][49][50][51][52]. Over the past decade, the Panx1 channel has been explored as a target in various brain pathologies (see Table 1). Below, we focus on specific CNS pathologies where Panx1 channels have been reported to play a role in tissue injury and the neuroinflammatory response.
Table 1. Summary of Panx1 function in different pathophysiologies.
Pathophysiology Pharmacological Blockade of Panx1 Genetic Deletion Outcome
Epilepsy Probenecid and mefloquine Global Panx1 KO Blocked Ictal discharge and resistance to Kainic induced seizure (Dossi et al., 2018)
Spinal cord injury 10Panx, Mefloquine, Probenecid Microglia Panx1 KO Reduces Morphine withdrawal and joint pain by mechanical allodynia (Mousseau et al., 2018) (Burma et al., 2017)
Sciatic Nerve injury (Neuropathic pain) Carbenoxolone and Trovafloxacin Global Panx1 KO
Myeloid Panx1 (Microglia and infiltrating monocytes) KO		 Blockers reduced hypersensitivity to tactile and thermal stimuli
Myeloid Panx1 KO did not reduced neuropathic pain (Weaver et al., 2017)
Ischemia (MCAO) Probenecid Global Panx1 KO
Double KO of Panx1 and Panx2		 Probenecid reduced neuronal death and inflammasome activation in rat model of ischemia.(Wei et al., 2015)
Panx1 KO did not show neuroprotection but Double KO of Panx1 and Panx2 showed reduced neurological deficits and reduced infarct volume compared to WT in MCAO model (Bargiotas et al., 2011)
Ischemia/Reperfusion Probenecid, mefloquine, Carbenoxolone Global Panx1 KO Blockers as well as Panx1 KO showed reduced infarct volume, neuronal and tissue damage and improved motor function. (Cisneros-Mejorado et al., 2015)
Traumatic brain injury Trovafloxacin(TVX) Myeloid Panx1 KO TVX reduced macrophage infiltration and astrogliosis correlated with improvement in locomotor activity(Garg et al., 2018)
Myeloid Panx1 KO showed improved motor co-ordination, memory outcomes, reduced tissue damage, less BBB leakage and less infiltration of leukocytes (Seo et al., 2020)
Experimental Autoimmune Encephalopathy Mefloquine Global Panx1 KO Panx1 KO mice showed delayed onset of clinical signs of EAE and decreased mortality rate compared to WT mice
Mefloquine (MFQ) reduced severity of acute and chronic EAE (Lutz, S.E., et al., 2013)

3.1. Spinal Cord Injury, Neuropathic Pain, and Orofacial Pain

The neuroinflammatory response produced by spinal cord or nerve injury has been recently associated with Panx1 channel activation in astrocytes and microglia [53][54][55]. Garre et al. showed that the inflammatory action of the fibroblast growth factor-1 (FGF-1) is mediated by the opening of both Cx43 hemichannels and Panx1 channels in astrocytes from spinal cord slices. This response is first initiated by activation of the astrocytic Panx1 channel, which leads to an increase in membrane permeability to small molecules, elevated levels of intracellular calcium, and ATP release [56]. FGF-1-induced Panx1 activation then promotes the activation of microglia, enhancing the release of pro-inflammatory cytokines through a mechanism depending on P2X7 receptors. The authors suggested this circuit favors the recruitment of leukocytes into the injured spinal cord impacting negatively on neuronal function and survival. Consistently, a sole study has also shown that blockade or global deletion of Panx1 channels reduced spinal cord inflammatory lesion in a mice model of experimental autoimmune encephalomyelitis (EAE). The global deletion of Panx1 also delayed clinical signs of EAE and decreased mortality when compared to wild type animals. The specific role of different cell types expressing Panx1 in this model, however, remains to be established [57].
The negative effects of opioid withdrawal and neuropathic pain that affect the spinal cords normal function have been recently associated with the activation of microglia Panx1 channels [58]. The group of Trang has shown that blockade of Panx1 channels or specific deletion of microglial Panx1 channels alleviates morphine withdrawal, likely via the inhibition of ATP release. It is established that withdrawal from morphine induces long-term synaptic facilitation in specific neuronal layers of the spinal dorsal horn that mediate opiate analgesia. Pharmacological blockade of the Panx1 channel or microglia-specific Panx-1 deletion prevent the synaptic facilitation mediated by morphine withdrawal. The same group later demonstrated that deletion of microglial Panx1 channels also alleviated the joint pain caused by mechanical allodynia. [58]. The authors proposed that the purinergic receptor P2X7, an established mediator of joint pain caused by intra-articular injection of monosodium iodoacetate, activates panx1 in spinal microglia cells. Panx1 channel activation leads to release of the pro-inflammatory cytokine IL-1β, which is an important mediator of the neuroinflammatory response [58]. Consistently, the Bayliss group showed that deletion of Panx1 from myeloid cells (microglia and infiltrating monocytes) or treatment with Panx1 channel blockers attenuated early development of hypersensitivity to tactile and thermal stimuli induced by two types of nerve injury [55]. Interestingly, the author proposed that myeloid Panx1 channel activation in nerved injury-induced pain relies on Panx-1 protein phosphorylation at residue Y198A. This was supported by the experiments where transplantation of bone marrow cell expressing mutant Panx1-Y198A failed to rescue mechanical allodynia when compared to those transplanted with wild-type Panx1 [55]. Since Panx1 channels are phosphorylated at residue Y198 by a number of Gq-linked receptors, the authors suggested that Gq-linked receptors implicated in neuropathic pain, such as P2Y, histamine, and metabotropic glutamate receptors, could play a role in the activation of Panx1 channels in myeloid cells [55].
It has previously been shown that Panx1 channels are expressed in high levels in satellite glial cells (SGC) and trigeminal ganglion cells (TGC) [59]. Since the trigeminal nerve sends pain signals from the craniofacial areas to the central nervous system [60], it is plausible that Panx1 may be involved in these processes. Indeed, there is evidence that Panx1 channels may play a role in orofacial pain and migraine with visual or sensory aura [61][62]. Hanstein and colleagues demonstrated that, using a mouse model of chronic orofacial pain and astrocyte or neuron-specific Panx1 knock out mice, Panx1 channels in astrocytes and neurons contribute to tactile hypersensitivity [62]. More specifically, they showed that while deletion of Panx1 in GFAP-positive astrocytes completely prevented hypersensitivity, deletion of Panx1 in neurons reduced baseline sensitivity and the period of hypersensitivity [62].
Cortical spreading depression (CSD) is a phenomenon where slowly propagating waves of depolarization are followed by low brain activity [63]. CSD is thought to be the main cause of migraines with visual and auditory aura by activating perivascular trigeminal nerves [64][65][66][67]. Karatas and colleagues demonstrated that CSD caused neuronal Panx1 channel opening and caspase-1 activation, which was followed by the release of inflammatory molecules such as high-mobility group box 1 (HMGB1). They showed that cleaved caspase-1 and HMGB1 are only found in neurons where Panx1 channels are activated. The authors suggested that the inflammatory response triggered by opening of neuronal Panx1 channels further lead to astrocyte activation via the NF-κB pathway [40]. CSD is known to cause elevation in blood flow in the middle meningeal artery (MMA), followed by the dialation of MMA [68]. Treatment with the Panx1 inhibitor, carbenoxolone, completely inhibited MMA dilation, suggesting that Panx1 channels could contributed to CSD-induced trigeminal nerve activation [61]. Together, the evidence suggests that Panx1 channels are important conduits in the transmission of pain, and that they may represent a novel therapeutic target for different kinds of pain, including neuropathic pain, migraine with aura, and orofacial pain.

3.2. Brain Ischemia

Stroke is a cerebrovascular event where blood flow is blocked in a particular region of the brain, leading to cell death and inflammation [8]. Stroke is one of the five leading causes of death in the United States, and it causes major disability in survivors [69]. It can be categorized into two large categories, ischemic and hemorrhagic; ischemic stroke being by far the most prevalent, accounting for around 87% of all strokes [70]. In ischemic stroke, blood supply is obstructed by fatty buildups, called plaques. Ischemic stroke initiates a complex series of molecular events that lead to necrosis and apoptosis, followed by subsequent neuroinflammation [71].
With the acute cessation of blood supply and oxygen after an ischemic stroke, neurons in the affected area experience a catastrophic energetic failure, because aerobic production ATP is halted while the consumption remains constant [69]. Reduction in intracellular ATP induces depolarization of membrane potential leading to the activation of various ion channels, which results in disruption of ionic homeostasis [72]. Neuronal Panx1 channels, first demonstrated by Thompson and his colleagues, have been shown to activate early on after oxygen glucose deprivation in an in vitro model of ischemia [40]. As shown in Figure 2, they further showed that the neuronal Panx1 channel, the N-Methyl-D-Aspartate receptor (NMDAR), and the sarcoma (Src) kinase form a signaling complex that mediates neuronal death during anoxia-induced excitotoxicity in vitro and in vivo [30][40]. They concluded that the opening of Panx1 channels may be the major contributor to the dysregulation of ionic fluxes that leads to neuronal necrosis after ischemia [30][73][40].
In response to ischemic insult, neuronal necrosis and debris can activate microglia and astrocytes, which initiate the secondary neuroinflammatory events, including leukocyte infiltration. One of the key inflammatory molecules produced and released by microglia and astrocytes is IL-1β, which has a wide range of inflammatory effects [74]. IL-1β is mainly produced by inflammasome complexes that involve NLRP3, ASC, NEK7, and caspase-1 proteins [25]. A key signaling pathway that could lead to inflammasome activation is extracellular ATP acting on P2X7 receptors [75]. The evidence suggests that activation of Panx1 channels by injury increases the extracellular levels of ATP, which feeds back on P2X 7 receptors. This feed forward reaction triggers potassium efflux via P2X 7, which induces the formation of an active inflammasome complex [25]. While it is possible that the Panx1-P2X 7 signaling complex drives inflammation and secondary damage after ischemic injury, current data are conflicting. While some lines of evidence indicate that inhibition of Panx1 channels leads to positive outcomes after ischemia, others suggest that Panx1 channels do not contribute to injury. For example, Bargiotas and colleagues found that genetic deletion of Panx1 protein did not protect from middle cerebral artery occlusion (MCAO) in a mouse model of cerebral ischemia [76]. However, a double knockout mouse line, were both Panx1 and Panx2 were deleted, displayed neuroprotection. On the other hand, the administration of probenecid, a well-known Panx1 inhibitor, resulted in reduction of neuronal death and inflammasome activation in a rat model of ischemia [77]. Similarly, Cisneros-Mejorado and colleagues found that Panx1 channel inhibitors or Panx1 knockout mice showed a reduction of infarct volumes and improved motor function after ischemia/reperfusion injury in mice [78]. Freitas-Andrade and his colleagues suggested that the conflicting data from the literature may have arisen from the sex of the animals, or the steroid hormone status of the animal during the experiments [79]. They found that in female Panx1 knock out mice, infarct volume, astrogliosis, and microgliosis were significantly reduced, while such neuroprotection was not seen in male Panx1 knock out mice [79].

3.3. Traumatic Brain Injury

TBI impacts more than 10 million people worldwide every year, and it is responsible for 50,000 deaths and leaves more than 80,000 with permanent disabilities [80]. The pathophysiology of TBI largely consists of two distinct events: while primary injury occurs immediately after an impact to the head and results in necrotic death of glial cells, neurons, and blood vessels [81][82][83][84], secondary injury occurs days to weeks later, and it accompanies the sustained oxidative stress, excitotoxicity, and mitochondrial dysfunction caused by hypoxic-ischemic damage [80]. Neuroinflammation is a major constituent of the secondary injury, and if it is left unresolved, it can exacerbate the outcomes after TBI [85]. As mentioned above, DAPMS release upon trauma causes activation of astrocytes and microglia, which release a plethora of pro-inflammatory proteinases, cytokines, and chemokines into the parenchyma, leading to disruption of blood–brain barrier and infiltration of peripheral cells including leukocytes [86]. Depletion of neutrophils or blocking CD11d receptor improved neurological score, brain edema, and tissue damage after experimental TBI [87][88]. Moreover, genetic approaches that disrupted chemokine signaling in myeloid cells, including CCL2/CCR2 and CX3CL1/CX3CR1, showed acute protection after TBI in mouse models [89][90].
An important signaling pathway that is involved in chemotaxis is mediated by activation of purinergic (P2X and P2Y) receptors by ATP [91]. Pharmacological and genetic inhibition of various purinergic receptors reduced neuroinflammation, leading to improved outcomes in mouse models of spinal cord injury and TBI [92][93][94][95]. These results suggests that interdicting ATP release and the subsequent purinergic signaling can potentially serve as therapeutic targets. Using a controlled cortical impact (CCI) model to study brain trauma, our laboratory demonstrated a critical role of Panx1 channels in the development of neuroinflammatory response. We first showed that pharmacological blockade of Panx1 channels with Trovafloxacin significantly reduced macrophage infiltration and astrogliosis after TBI. These results correlated with an improvement in locomotor activity [96]. More recently, we showed that genetic deletion of Panx1 in myeloid cells, namely brain-resident microglia and infiltrating macrophages, led to an overall reduction in the infiltration of peripheral neutrophils and macrophages, as soon as 3 days after CCI injury [24]. Myeloid Panx1 conditional knockout mice also showed lower biomarkers of tissue damage, including a reduced level of α-II spectrin breakdown products and MMP9 [24]. Finally, the myeloid Panx1 conditional knockout mice showed improved motor function and blood–brain barrier dysfunction compared to control mice [24]. Overall, these data indicated that myeloid Panx1 channel activation play detrimental roles in brain trauma. Intriguingly, it has been recently proposed that serum Panx1 levels can serve as biomarker outcome for TBI patients [97]. Panx1 protein levels in the serum of TBI patients were significantly higher when compared to control individuals. Moreover, a negative correlation between Panx1 levels in the serum and favorable outcomes in the patients was found [97]. A concern with these findings is that Panx1 serum levels were almost as high as normal plasma levels of albumin. Thus, further studies are needed to validate these results in TBI patients.

References

  1. Cova, I.; Markova, A.; Campini, I.; Grande, G.; Mariani, C.; Pomati, S. Worldwide trends in the prevalence of dementia. J. Neurol. Sci. 2017, 379, 259–260.
  2. Virani, S.S.; Alonso, A.; Benjamin, E.J.; Bittencourt, M.S.; Callaway, C.W.; Carson, A.P.; Chamberlain, A.M.; Chang, A.R.; Cheng, S.; Delling, F.N.; et al. Heart disease and stroke statistics—2020 update: A report from the American Heart Association. Circulation 2020, 141, E139–E596.
  3. Taylor, C.A.; Bell, J.M.; Breiding, M.J.; Xu, L. Traumatic brain injury-related emergency department visits, hospitalizations, and deaths—United States, 2007 and 2013. MMWR Surveill. Summ. 2017, 66, 1–16.
  4. Kacirova, M.; Zmeskalova, A.; Korinkova, L.; Zelezna, B.; Kunes, J.; Maletinska, L. Inflammation: Major denominator of obesity, Type 2 diabetes and Alzheimer’s disease-like pathology? Clin. Sci. 2020, 134, 547–570.
  5. Hur, J.Y.; Frost, G.R.; Wu, X.; Crump, C.; Pan, S.J.; Wong, E.; Barros, M.; Li, T.; Nie, P.; Zhai, Y.; et al. The innate immunity protein IFITM3 modulates gamma-secretase in Alzheimer’s disease. Nature 2020, 586, 735–740.
  6. Iannucci, J.; Renehan, W.; Grammas, P. Thrombin, a Mediator of Coagulation, Inflammation, and Neurotoxicity at the Neurovascular Interface: Implications for Alzheimer’s Disease. Front. Neurosci. 2020, 14, 762.
  7. Ziebell, J.M.; Rowe, R.K.; Muccigrosso, M.M.; Reddaway, J.T.; Adelson, P.D.; Godbout, J.P.; Lifshitz, J. Aging with a traumatic brain injury: Could behavioral morbidities and endocrine symptoms be influenced by microglial priming? Brain Behav. Immun. 2017, 59, 1–7.
  8. Anrather, J.; Iadecola, C. Inflammation and Stroke: An Overview. Neurotherapeutics 2016, 13, 661–670.
  9. Swanson, K.V.; Deng, M.; Ting, J.P. The NLRP3 inflammasome: Molecular activation and regulation to therapeutics. Nat. Rev. Immunol. 2019, 19, 477–489.
  10. Shabab, T.; Khanabdali, R.; Moghadamtousi, S.Z.; Kadir, H.A.; Mohan, G. Neuroinflammation pathways: A general review. Int. J. Neurosci. 2017, 127, 624–633.
  11. Bruzzone, R.; Hormuzdi, S.G.; Barbe, M.T.; Herb, A.; Monyer, H. Pannexins, a family of gap junction proteins expressed in brain. Proc. Natl. Acad. Sci. USA 2003, 100, 13644–13649.
  12. Dvoriantchikova, G.; Ivanov, D.; Panchin, Y.; Shestopalov, V.I. Expression of pannexin family of proteins in the retina. FEBS Lett. 2006, 580, 2178–2182.
  13. Dvoriantchikova, G.; Ivanov, D.; Pestova, A.; Shestopalov, V. Molecular characterization of pannexins in the lens. Mol. Vis. 2006, 12, 1417–1426.
  14. Ray, A.; Zoidl, G.; Wahle, P.; Dermietzel, R. Pannexin expression in the cerebellum. Cerebellum 2006, 5, 189–192.
  15. Ray, A.; Zoidl, G.; Weickert, S.; Wahle, P.; Dermietzel, R. Site-specific and developmental expression of pannexin1 in the mouse nervous system. Eur. J. Neurosci. 2005, 21, 3277–3290.
  16. Sohl, G.; Maxeiner, S.; Willecke, K. Expression and functions of neuronal gap junctions. Nat. Rev. Neurosci. 2005, 6, 191–200.
  17. Shestopalov, V.I.; Panchin, Y. Pannexins and gap junction protein diversity. Cell Mol. Life Sci. 2008, 65, 376–394.
  18. Vogt, A.; Hormuzdi, S.G.; Monyer, H. Pannexin1 and Pannexin2 expression in the developing and mature rat brain. Brain Res. Mol. Brain Res. 2005, 141, 113–120.
  19. Weickert, S.; Ray, A.; Zoidl, G.; Dermietzel, R. Expression of neural connexins and pannexin1 in the hippocampus and inferior olive: A quantitative approach. Brain Res. Mol. Brain Res. 2005, 133, 102–109.
  20. Zappala, A.; Cicero, D.; Serapide, M.F.; Paz, C.; Catania, M.V.; Falchi, M.; Parenti, R.; Panto, M.R.; La Delia, F.; Cicirata, F. Expression of pannexin1 in the CNS of adult mouse: Cellular localization and effect of 4-aminopyridine-induced seizures. Neuroscience 2006, 141, 167–178.
  21. Zoidl, G.; Petrasch-Parwez, E.; Ray, A.; Meier, C.; Bunse, S.; Habbes, H.W.; Dahl, G.; Dermietzel, R. Localization of the pannexin1 protein at postsynaptic sites in the cerebral cortex and hippocampus. Neuroscience 2007, 146, 9–16.
  22. Penuela, S.; Gehi, R.; Laird, D.W. The biochemistry and function of pannexin channels. Biochim. Biophys. Acta 2013, 1828, 15–22.
  23. Saez, P.J.; Vargas, P.; Shoji, K.F.; Harcha, P.A.; Lennon-Dumenil, A.M.; Saez, J.C. ATP promotes the fast migration of dendritic cells through the activity of pannexin 1 channels and P2X7 receptors. Sci. Signal. 2017, 10, eaah7107.
  24. Seo, J.H.; Dalal, M.S.; Calderon, F.; Contreras, J.E. Myeloid Pannexin-1 mediates acute leukocyte infiltration and leads to worse outcomes after brain trauma. J. Neuroinflamm. 2020, 17, 245.
  25. Di Virgilio, F.; Dal Ben, D.; Sarti, A.C.; Giuliani, A.L.; Falzoni, S. The P2X7 Receptor in Infection and Inflammation. Immunity 2017, 47, 15–31.
  26. Chekeni, F.B.; Elliott, M.R.; Sandilos, J.K.; Walk, S.F.; Kinchen, J.M.; Lazarowski, E.R.; Armstrong, A.J.; Penuela, S.; Laird, D.W.; Salvesen, G.S.; et al. Pannexin 1 channels mediate ‘find-me’ signal release and membrane permeability during apoptosis. Nature 2010, 467, 863–867.
  27. Bravo, D.; Ibarra, P.; Retamal, J.; Pelissier, T.; Laurido, C.; Hernandez, A.; Constandil, L. Pannexin 1: A novel participant in neuropathic pain signaling in the rat spinal cord. Pain 2014, 155, 2108–2115.
  28. Zhang, Y.; Laumet, G.; Chen, S.R.; Hittelman, W.N.; Pan, H.L. Pannexin-1 Up-regulation in the Dorsal Root Ganglion Contributes to Neuropathic Pain Development. J. Biol. Chem. 2015, 290, 14647–14655.
  29. Chiu, Y.H.; Schappe, M.S.; Desai, B.N.; Bayliss, D.A. Revisiting multimodal activation and channel properties of Pannexin 1. J. Gen. Physiol. 2018, 150, 19–39.
  30. Weilinger, N.L.; Lohman, A.W.; Rakai, B.D.; Ma, E.M.; Bialecki, J.; Maslieieva, V.; Rilea, T.; Bandet, M.V.; Ikuta, N.T.; Scott, L.; et al. Metabotropic NMDA receptor signaling couples Src family kinases to pannexin-1 during excitotoxicity. Nat. Neurosci. 2016, 19, 432–442.
  31. Lohman, A.W.; Leskov, I.L.; Butcher, J.T.; Johnstone, S.R.; Stokes, T.A.; Begandt, D.; DeLalio, L.J.; Best, A.K.; Penuela, S.; Leitinger, N.; et al. Pannexin 1 channels regulate leukocyte emigration through the venous endothelium during acute inflammation. Nat. Commun. 2015, 6, 7965.
  32. Sanchez-Arias, J.C.; van der Slagt, E.; Vecchiarelli, H.A.; Candlish, R.C.; York, N.; Young, P.A.; Shevtsova, O.; Juma, A.; Tremblay, M.E.; Swayne, L.A. Purinergic signaling in nervous system health and disease: Focus on pannexin 1. Pharmacol. Ther. 2021, 107840.
  33. Ishikawa, M.; Williams, G.L.; Ikeuchi, T.; Sakai, K.; Fukumoto, S.; Yamada, Y. Pannexin 3 and connexin 43 modulate skeletal development through their distinct functions and expression patterns. J. Cell Sci. 2016, 129, 1018–1030.
  34. Zhang, P.; Ishikawa, M.; Doyle, A.; Nakamura, T.; He, B.; Yamada, Y. Pannexin 3 regulates skin development via Epiprofin. Sci. Rep. 2021, 11, 1779.
  35. Scemes, E.; Spray, D.C.; Meda, P. Connexins, pannexins, innexins: Novel roles of “hemi-channels”. Pflug. Arch. 2009, 457, 1207–1226.
  36. Pelegrin, P.; Surprenant, A. Pannexin-1 mediates large pore formation and interleukin-1beta release by the ATP-gated P2X7 receptor. EMBO J. 2006, 25, 5071–5082.
  37. Illes, P. P2X7 Receptors Amplify CNS Damage in Neurodegenerative Diseases. Int. J. Mol. Sci. 2020, 21, 5996.
  38. Freeman, T.J.; Sayedyahossein, S.; Johnston, D.; Sanchez-Pupo, R.E.; O’Donnell, B.; Huang, K.; Lakhani, Z.; Nouri-Nejad, D.; Barr, K.J.; Harland, L.; et al. Inhibition of Pannexin 1 Reduces the Tumorigenic Properties of Human Melanoma Cells. Cancers 2019, 11, 102.
  39. Graham, S.V.; Jiang, J.X.; Mesnil, M. Connexins and Pannexins: Important Players in Tumorigenesis, Metastasis and Potential Therapeutics. Int. J. Mol. Sci. 2018, 19, 1645.
  40. Thompson, R.J.; Zhou, N.; MacVicar, B.A. Ischemia opens neuronal gap junction hemichannels. Science 2006, 312, 924–927.
  41. Taylor, K.A.; Wright, J.R.; Vial, C.; Evans, R.J.; Mahaut-Smith, M.P. Amplification of human platelet activation by surface pannexin-1 channels. J. Thromb. Haemost. 2014, 12, 987–998.
  42. Dossi, E.; Blauwblomme, T.; Moulard, J.; Chever, O.; Vasile, F.; Guinard, E.; Le Bert, M.; Couillin, I.; Pallud, J.; Capelle, L.; et al. Pannexin-1 channels contribute to seizure generation in human epileptic brain tissue and in a mouse model of epilepsy. Sci. Transl. Med. 2018, 10, eaar3796.
  43. Orellana, J.A.; Velasquez, S.; Williams, D.W.; Saez, J.C.; Berman, J.W.; Eugenin, E.A. Pannexin1 hemichannels are critical for HIV infection of human primary CD4+ T lymphocytes. J. Leukoc. Biol. 2013, 94, 399–407.
  44. Scemes, E.; Velisek, L.; Veliskova, J. Astrocyte and Neuronal Pannexin1 Contribute Distinctly to Seizures. ASN Neuro 2019, 11.
  45. Santiago, M.F.; Veliskova, J.; Patel, N.K.; Lutz, S.E.; Caille, D.; Charollais, A.; Meda, P.; Scemes, E. Targeting pannexin1 improves seizure outcome. PLoS ONE 2011, 6, e25178.
  46. Allan, S.M.; Rothwell, N.J. Inflammation in central nervous system injury. Philos. Trans. R. Soc. Lond. B Biol. Sci. 2003, 358, 1669–1677.
  47. Liddelow, S.A.; Guttenplan, K.A.; Clarke, L.E.; Bennett, F.C.; Bohlen, C.J.; Schirmer, L.; Bennett, M.L.; Munch, A.E.; Chung, W.S.; Peterson, T.C.; et al. Neurotoxic reactive astrocytes are induced by activated microglia. Nature 2017, 541, 481–487.
  48. Zhou, Y.; Song, W.M.; Andhey, P.S.; Swain, A.; Levy, T.; Miller, K.R.; Poliani, P.L.; Cominelli, M.; Grover, S.; Gilfillan, S.; et al. Human and mouse single-nucleus transcriptomics reveal TREM2-dependent and TREM2-independent cellular responses in Alzheimer’s disease. Nat. Med. 2020, 26, 131–142.
  49. Ulland, T.K.; Song, W.M.; Huang, S.C.; Ulrich, J.D.; Sergushichev, A.; Beatty, W.L.; Loboda, A.A.; Zhou, Y.; Cairns, N.J.; Kambal, A.; et al. TREM2 Maintains Microglial Metabolic Fitness in Alzheimer’s Disease. Cell 2017, 170, 649–663.
  50. Tiwari, S.; Atluri, V.; Kaushik, A.; Yndart, A.; Nair, M. Alzheimer’s disease: Pathogenesis, diagnostics, and therapeutics. Int. J. Nanomed. 2019, 14, 5541–5554.
  51. Hong, S.; Beja-Glasser, V.F.; Nfonoyim, B.M.; Frouin, A.; Li, S.; Ramakrishnan, S.; Merry, K.M.; Shi, Q.; Rosenthal, A.; Barres, B.A.; et al. Complement and microglia mediate early synapse loss in Alzheimer mouse models. Science 2016, 352, 712–716.
  52. Yun, S.P.; Kam, T.I.; Panicker, N.; Kim, S.; Oh, Y.; Park, J.S.; Kwon, S.H.; Park, Y.J.; Karuppagounder, S.S.; Park, H.; et al. Block of A1 astrocyte conversion by microglia is neuroprotective in models of Parkinson’s disease. Nat. Med. 2018, 24, 931–938.
  53. Garre, J.M.; Retamal, M.A.; Cassina, P.; Barbeito, L.; Bukauskas, F.F.; Saez, J.C.; Bennett, M.V.; Abudara, V. FGF-1 induces ATP release from spinal astrocytes in culture and opens pannexin and connexin hemichannels. Proc. Natl. Acad. Sci. USA 2010, 107, 22659–22664.
  54. Burma, N.E.; Bonin, R.P.; Leduc-Pessah, H.; Baimel, C.; Cairncross, Z.F.; Mousseau, M.; Shankara, J.V.; Stemkowski, P.L.; Baimoukhametova, D.; Bains, J.S.; et al. Blocking microglial pannexin-1 channels alleviates morphine withdrawal in rodents. Nat. Med. 2017, 23, 355–360.
  55. Weaver, J.L.; Arandjelovic, S.; Brown, G.; Mendu, S.K.; Schappe, M.S.; Buckley, M.W.; Chiu, Y.H.; Shu, S.; Kim, J.K.; Chung, J.; et al. Hematopoietic pannexin 1 function is critical for neuropathic pain. Sci. Rep. 2017, 7, 42550.
  56. Garre, J.M.; Yang, G.; Bukauskas, F.F.; Bennett, M.V. FGF-1 Triggers Pannexin-1 Hemichannel Opening in Spinal Astrocytes of Rodents and Promotes Inflammatory Responses in Acute Spinal Cord Slices. J. Neurosci. 2016, 36, 4785–4801.
  57. Lutz, S.E.; Gonzalez-Fernandez, E.; Ventura, J.C.; Perez-Samartin, A.; Tarassishin, L.; Negoro, H.; Patel, N.K.; Suadicani, S.O.; Lee, S.C.; Matute, C.; et al. Contribution of pannexin1 to experimental autoimmune encephalomyelitis. PLoS ONE 2013, 8, e66657.
  58. Mousseau, M.; Burma, N.E.; Lee, K.Y.; Leduc-Pessah, H.; Kwok, C.H.T.; Reid, A.R.; O’Brien, M.; Sagalajev, B.; Stratton, J.A.; Patrick, N.; et al. Microglial pannexin-1 channel activation is a spinal determinant of joint pain. Sci. Adv. 2018, 4, eaas9846.
  59. Hanstein, R.; Negoro, H.; Patel, N.K.; Charollais, A.; Meda, P.; Spray, D.C.; Suadicani, S.O.; Scemes, E. Promises and pitfalls of a Pannexin1 transgenic mouse line. Front. Pharmacol. 2013, 4, 61.
  60. Chichorro, J.G.; Porreca, F.; Sessle, B. Mechanisms of craniofacial pain. Cephalalgia 2017, 37, 613–626.
  61. Karatas, H.; Erdener, S.E.; Gursoy-Ozdemir, Y.; Lule, S.; Eren-Kocak, E.; Sen, Z.D.; Dalkara, T. Spreading depression triggers headache by activating neuronal Panx1 channels. Science 2013, 339, 1092–1095.
  62. Hanstein, R.; Hanani, M.; Scemes, E.; Spray, D.C. Glial pannexin1 contributes to tactile hypersensitivity in a mouse model of orofacial pain. Sci. Rep. 2016, 6, 38266.
  63. Charles, A.C.; Baca, S.M. Cortical spreading depression and migraine. Nat. Rev. Neurol. 2013, 9, 637–644.
  64. Moskowitz, M.A. The neurobiology of vascular head pain. Ann. Neurol. 1984, 16, 157–168.
  65. Moskowitz, M.A.; Nozaki, K.; Kraig, R.P. Neocortical spreading depression provokes the expression of c-fos protein-like immunoreactivity within trigeminal nucleus caudalis via trigeminovascular mechanisms. J. Neurosci. 1993, 13, 1167–1177.
  66. Dalkara, T.; Zervas, N.T.; Moskowitz, M.A. From spreading depression to the trigeminovascular system. Neurol. Sci. 2006, 27 (Suppl. 2), S86–S90.
  67. Zhang, X.; Levy, D.; Noseda, R.; Kainz, V.; Jakubowski, M.; Burstein, R. Activation of meningeal nociceptors by cortical spreading depression: Implications for migraine with aura. J. Neurosci. 2010, 30, 8807–8814.
  68. Bolay, H.; Reuter, U.; Dunn, A.K.; Huang, Z.; Boas, D.A.; Moskowitz, M.A. Intrinsic brain activity triggers trigeminal meningeal afferents in a migraine model. Nat. Med. 2002, 8, 136–142.
  69. Xing, C.; Arai, K.; Lo, E.H.; Hommel, M. Pathophysiologic cascades in ischemic stroke. Int. J. Stroke 2012, 7, 378–385.
  70. Campbell, B.C.V.; De Silva, D.A.; Macleod, M.R.; Coutts, S.B.; Schwamm, L.H.; Davis, S.M.; Donnan, G.A. Ischaemic stroke. Nat. Rev. Dis. Primers 2019, 5, 70.
  71. Jin, R.; Liu, L.; Zhang, S.; Nanda, A.; Li, G. Role of inflammation and its mediators in acute ischemic stroke. J. Cardiovasc. Transl. Res. 2013, 6, 834–851.
  72. Santos, M.S.; Moreno, A.J.; Carvalho, A.P. Relationships between ATP depletion, membrane potential, and the release of neurotransmitters in rat nerve terminals. An in vitro study under conditions that mimic anoxia, hypoglycemia, and ischemia. Stroke 1996, 27, 941–950.
  73. Weilinger, N.L.; Tang, P.L.; Thompson, R.J. Anoxia-induced NMDA receptor activation opens pannexin channels via Src family kinases. J. Neurosci. 2012, 32, 12579–12588.
  74. Ogura, Y.; Sutterwala, F.S.; Flavell, R.A. The inflammasome: First line of the immune response to cell stress. Cell 2006, 126, 659–662.
  75. Savio, L.E.B.; de Andrade Mello, P.; da Silva, C.G.; Coutinho-Silva, R. The P2X7 Receptor in Inflammatory Diseases: Angel or Demon? Front. Pharmacol. 2018, 9, 52.
  76. Bargiotas, P.; Krenz, A.; Hormuzdi, S.G.; Ridder, D.A.; Herb, A.; Barakat, W.; Penuela, S.; von Engelhardt, J.; Monyer, H.; Schwaninger, M. Pannexins in ischemia-induced neurodegeneration. Proc. Natl. Acad. Sci. USA 2011, 108, 20772–20777.
  77. Wei, R.; Wang, J.; Xu, Y.; Yin, B.; He, F.; Du, Y.; Peng, G.; Luo, B. Probenecid protects against cerebral ischemia/reperfusion injury by inhibiting lysosomal and inflammatory damage in rats. Neuroscience 2015, 301, 168–177.
  78. Cisneros-Mejorado, A.; Gottlieb, M.; Cavaliere, F.; Magnus, T.; Koch-Nolte, F.; Scemes, E.; Perez-Samartin, A.; Matute, C. Blockade of P2X7 receptors or pannexin-1 channels similarly attenuates postischemic damage. J. Cereb. Blood Flow Metab. 2015, 35, 843–850.
  79. Freitas-Andrade, M.; Bechberger, J.F.; MacVicar, B.A.; Viau, V.; Naus, C.C. Pannexin1 knockout and blockade reduces ischemic stroke injury in female, but not in male mice. Oncotarget 2017, 8, 36973–36983.
  80. Prins, M.; Greco, T.; Alexander, D.; Giza, C.C. The pathophysiology of traumatic brain injury at a glance. Dis. Model Mech. 2013, 6, 1307–1315.
  81. Lumpkins, K.M.; Bochicchio, G.V.; Keledjian, K.; Simard, J.M.; McCunn, M.; Scalea, T. Glial fibrillary acidic protein is highly correlated with brain injury. J. Trauma 2008, 65, 778–782.
  82. Raghupathi, R. Cell death mechanisms following traumatic brain injury. Brain Pathol. 2004, 14, 215–222.
  83. Meaney, D.F.; Smith, D.H. Cellular biomechanics of central nervous system injury. Handb. Clin. Neurol. 2015, 127, 105–114.
  84. Takano, T.; Oberheim, N.; Cotrina, M.L.; Nedergaard, M. Astrocytes and ischemic injury. Stroke 2009, 40, S8–S12.
  85. Blennow, K.; Brody, D.L.; Kochanek, P.M.; Levin, H.; McKee, A.; Ribbers, G.M.; Yaffe, K.; Zetterberg, H. Traumatic brain injuries. Nat. Rev. Dis. Primers 2016, 2, 16084.
  86. Hanisch, U.K.; Kettenmann, H. Microglia: Active sensor and versatile effector cells in the normal and pathologic brain. Nat. Neurosci. 2007, 10, 1387–1394.
  87. Weaver, L.C.; Bao, F.; Dekaban, G.A.; Hryciw, T.; Shultz, S.R.; Cain, D.P.; Brown, A. CD11d integrin blockade reduces the systemic inflammatory response syndrome after traumatic brain injury in rats. Exp. Neurol. 2015, 271, 409–422.
  88. Kenne, E.; Erlandsson, A.; Lindbom, L.; Hillered, L.; Clausen, F. Neutrophil depletion reduces edema formation and tissue loss following traumatic brain injury in mice. J. Neuroinflamm. 2012, 9, 17.
  89. Morganti, J.M.; Jopson, T.D.; Liu, S.; Riparip, L.K.; Guandique, C.K.; Gupta, N.; Ferguson, A.R.; Rosi, S. CCR2 antagonism alters brain macrophage polarization and ameliorates cognitive dysfunction induced by traumatic brain injury. J. Neurosci. 2015, 35, 748–760.
  90. Hsieh, C.L.; Niemi, E.C.; Wang, S.H.; Lee, C.C.; Bingham, D.; Zhang, J.; Cozen, M.L.; Charo, I.; Huang, E.J.; Liu, J.; et al. CCR2 deficiency impairs macrophage infiltration and improves cognitive function after traumatic brain injury. J. Neurotrauma 2014, 31, 1677–1688.
  91. Junger, W.G. Immune cell regulation by autocrine purinergic signalling. Nat. Rev. Immunol. 2011, 11, 201–212.
  92. Alves, M.; Beamer, E.; Engel, T. The Metabotropic Purinergic P2Y Receptor Family as Novel Drug Target in Epilepsy. Front. Pharmacol. 2018, 9, 193.
  93. de Rivero Vaccari, J.P.; Bastien, D.; Yurcisin, G.; Pineau, I.; Dietrich, W.D.; De Koninck, Y.; Keane, R.W.; Lacroix, S. P2X4 receptors influence inflammasome activation after spinal cord injury. J. Neurosci. 2012, 32, 3058–3066.
  94. Ulmann, L.; Hatcher, J.P.; Hughes, J.P.; Chaumont, S.; Green, P.J.; Conquet, F.; Buell, G.N.; Reeve, A.J.; Chessell, I.P.; Rassendren, F. Up-regulation of P2X4 receptors in spinal microglia after peripheral nerve injury mediates BDNF release and neuropathic pain. J. Neurosci. 2008, 28, 11263–11268.
  95. Choo, A.M.; Miller, W.J.; Chen, Y.C.; Nibley, P.; Patel, T.P.; Goletiani, C.; Morrison, B., 3rd; Kutzing, M.K.; Firestein, B.L.; Sul, J.Y.; et al. Antagonism of purinergic signalling improves recovery from traumatic brain injury. Brain 2013, 136, 65–80.
  96. Garg, C.; Seo, J.H.; Ramachandran, J.; Loh, J.M.; Calderon, F.; Contreras, J.E. Trovafloxacin attenuates neuroinflammation and improves outcome after traumatic brain injury in mice. J. Neuroinflamm. 2018, 15, 42.
  97. Ni, B.K.; Cai, J.Y.; Lin, Q.; Zheng, K.H.; Lin, L.; Wu, J.H. Evaluation of serum pannexin-1 as a prognostic biomarker for traumatic brain injury. Clin. Chim. Acta 2019, 488, 159–164.
More
© Text is available under the terms and conditions of the Creative Commons Attribution (CC BY) license; additional terms may apply. By using this site, you agree to the Terms and Conditions and Privacy Policy.
Upload a video for this entry
Information
Subjects: Cell Biology
Contributor MDPI registered users' name will be linked to their SciProfiles pages. To register with us, please refer to https://encyclopedia.pub/register :
Jorge E. Contreras
View Times: 658
Revisions: 2 times (View History)
Update Date: 25 May 2021
Table of Contents
    1000/1000
    Hot Most Recent
    Feedback