The integrity and thus the function of blood–brain barrier (BBB) TJs play a crucial role in the pathomechanism of neuroinflammatory and neurodegenerative diseases. Previously, it has been suggested that targeting different elements of the zonulin pathway, including actin filaments, TJs, or NF-κB, have potential therapeutic effects on CNS diseases. Indeed, encouraging results are accumulating from a recent preclinical study, using myosin light chain kinase (MLCK) inhibitor ML-7, which attenuates BBB disruption by preventing the disintegration of actin cytoskeletal microfilaments. Similarly, blocking the cleavage of TJ proteins by matrix metalloproteases (MMP) inhibitors, using either direct (broad-spectrum or selective MMP-2 and MMP-9) or indirect inhibitors (COX) has been shown to protect BBB. Peroxisome proliferator-activated receptor-γ (PPAR-γ) agonists, such as rosiglitazone, pioglitazone, or D-allose, also prevented BBB integrity by inhibiting NF-κB activation. Therefore, the use of zonulin inhibitors seems to be justified in the treatment of CNS diseases.
Model | Species | Administration | Daily Dose | Results | Ref. | ||||
---|---|---|---|---|---|---|---|---|---|
celiac disease | gliadin-sensitized HLA-HCD4/DQ8 transgenic mouse | p.o. gavage |
0.25 mg | reduced intestinal permeability and macrophage infiltration | [21] | ||||
p.o. | NCT00386165 | gavage | [ | 4] | |||||
0.3 mg | reduced intestinal permeability | [ | 22] | Celiac disease, gluten challenge | improvement in GI symptoms, | ||||
intestinal permeability | good tolerability | Il10−/− mouse | Phase IIa (80) |
NCT00362856 | p.o. gavage[5][6] |
5 mg[7][8] | |||
reduced intestinal permeability and inflammation | [ | 23 | ] | Celiac disease, gluten challenge | improvement in histological scores, good tolerability |
Phase IIb | |||
spontaneous colitis | (105) | p.o. NCT00620451 | [9][10] | ||||||
in drinking water | 0.1 or 1 mg/mL | reduced intestinal permeability and inflammation | [24] | Celiac disease, gluten challenge | improvement in GI symptoms, decreased level of anti-tTG IgA | Phase IIb (171) |
NCT00492960 | [11][12] |
Target | Type | Compound | Cell Line | Effect on TJs and/or Transcellular Permeability |
Ref. | |||
---|---|---|---|---|---|---|---|---|
PAR2 | peptidic antagonist | FSLLRY-NH2 | pHNECs | harmful | [46] | |||
SLIGRL-NH2 | ||||||||
non-peptidic full agonist | AC-55541 | hBMECs | protective | [50] | ||||
small molecule antagonist | GB88 | A549 | [48 | |||||
DSS induced colitis | zonulin transgenic mouse | p.o. in drinking water |
1 mg/mL | reduced intestinal permeability | [25] | |||
Celiac disease, persistent symptoms with gluten-free diet | improvement in GI and extra-GI symptoms, good tolerability |
Phase IIb (342) |
NCT01396213 | [13][14] | ||||
radiation-induced enteropathy | mouse | i.p. | 0.25 mg | improved clinical state and histological scores, inhibited bacterial translocation, elevated TJ protein levels | [26] | |||
] | healthy (pharmacokinetics) |
pig | p.o. capsule |
0.05 mg/kg | determining pharmacokinetics of larazotide acetate in the small intestine | [27] | COVID19—MIS-C | improvement in clinical symptoms, decreased level of inflammatory markers and SARS-CoV-2 nucleocapsid (N) protein |
Ruminococcus blautia gnavus colonization | case report | (1) |
germ-free mouse | p.o. in drinking water[ |
0.15 mg/mL17] | |||
reduced intestinal permeability | [ | 28 | ] | COVID19—MIS-C | improvement in GI symptoms, decreased level of SARS-CoV-2 Spike (S) protein | |||
spontaneous T1D | BB diabetic-prone rat | case series (4) |
[18] | |||||
p.o. | COVID19—MIS-C | (not completed) | Phase IIa (20) |
NCT05022303 | [19] |
in drinking water | |||||
0.01 mg/mL | |||||
inhibited development of diabetes | |||||
[ | |||||
29 | |||||
] | |||||
rheumatoid arthritis | mouse | p.o. in drinking water |
0.15 mg/mL | attenuated arthritis | [30] |
Il10ra−/− mouse, Cldn8−/− mouse |
p.o. gavage |
2 × 0.05 mg | reduced intestinal permeability, inflammation, and joint swelling | [31] | |
vasculitis | mouse | i.p. | 0.5 mg | reduced intestinal permeability and LPS translocation, prevented cardiovascular lesions | [32] |
LPS-induced acute lung injury | i.t. | 0.05 mg | |||
hECs | [49] | ||||
GB83 | Caco2 | harmful | [47] | ||
EGFR | tyrosine kinase inhibitor | AG1478 | hCMEC/D3 | protective | [51] |
Calu-3 | [52] | ||||
HSC-3 | [53] | ||||
erlotinib | IEC-6 | harmful | [54] | ||
gefitinib | reduced severity, decreased inflammatory markers | [ | 33 | ] | |
[ | i.v. | 0.01 or 0.025 or 0.05 mg | |||
55 | ] | influenza | i.v. | ||
icotinib | 0.15 mg | reduced severity of acute lung injury | [ | 34] | |
salivary gland fibrosis | |||||
dacomitinib | T84 | [57] | i.p. | 5 mg/kg | |
lapatinib | HBCCs | [58] | |||
vandetanib | Calu-6 | [59] | improved epithelial barrier function, ameliorated fibrosis | [35] | |
NAFLD | p.o. in drinking water |
0.1 or 1 mg/mL | reduced intestinal permeability | [36] | |
p.o. gavage |
2 × 0.03 or 2 × 0.3 mg | ||||
acute liver failure | rat | p.o. in drinking water |
0.01 mg/mL | decreased intestinal damage | [37] |
p.o. gavage |
2 × 0.03 mg |