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Topic Review
Sirtuin 1 in Male Germ Cells
Reproduction is the way to immortality for an individual, and it is essential to the continuation of the species. Sirtuins are involved in cellular homeostasis, energy metabolism, apoptosis, age-related problems, and sexual reproduction. Sirtuin 1 (SIRT1) belongs to the sirtuin family of deacetylases, and it is a nicotinamide adenine dinucleotide (NAD)-dependent deacetylase. It removes the acetyl group from a variety of substrates. SIRT1 regulates endocrine/metabolic, reproductive, and placental development by deacetylating histone, different transcription factors, and signal transduction molecules in a variety of cellular processes. It also plays a very important role in the synthesis and secretion of sex hormones via regulating the hypothalamus-pituitary-gonadal (HPG) axis. Moreover, SIRT1 participates in several key stages of spermatogenesis and sperm maturation. 
  • 325
  • 13 Apr 2022
Topic Review
SIRT7
Sirtuins are key players for maintaining cellular homeostasis and are often deregulated in different human diseases. SIRT7 is the only member of mammalian sirtuins that principally resides in the nucleolus, a nuclear compartment involved in ribosomal biogenesis, senescence, and cellular stress responses. The ablation of SIRT7 induces global genomic instability, premature ageing, metabolic dysfunctions, and reduced stress tolerance, highlighting its critical role in counteracting ageing-associated processes.
  • 779
  • 15 Oct 2021
Topic Review
SIRT3 in Regulating Mitochondrial Function
Mitochondrial function is finely regulated by post-translational modification of proteins and enzymes by reversible phosphorylation and acylation such as acetylation, malonylation and succinylation. SIRT3 is one of the sirtuin family enzymes that catalyzes the NAD+-dependent deacetylation of a myriad of mitochondrial proteins. SIRT3 deacetylates and activates polypeptides constituting respiratory enzyme complexes and several antioxidant enzymes. Deacetylation and activation of Foxo3a by SIRT3 increases the expression of Parkin and facilitates the mitochondrial quality control by mitophagy. SIRT3 regulates mitochondrial Ca2+ uptake and controls the opening of permeability transition pore, and thereby plays a role in maintenance of Ca2+ homeostasis. It has been demonstrated that deficiency of SIRT3 can result in a decrease of respiration and oxidative phosphorylation and knockout of SIRT3 can impair antioxidant defense by reduction of the activity of MnSOD. SIRT3 is involved in the upregulation of MnSOD and catalase through the transcriptional activation by Foxo3a. Moreover, SIRT3 targets and activates isocitrate dehydrogenase and increase the production of NADPH to promote antioxidant capacity of mammalian cells.  On the other hand, oxidative stress can decrease the expression and activity of SIRT3 and impair the mitochondrial function. A deficiency of SIRT3 has been observed in the primary cultures of patients with mitochondrial disease such as CPEO and in mice with insulin resistance that are fed on the high-fat diet and diabetic rats, respectively. In summary, SIRT3 plays a pivotal role in the regulation of mitochondrial respiratory function and Ca2+ homeostasis and in the maintenance of redox homeostasis through transcriptional activation of Foxo3a to increase the expression of MnSOD and catalse and deacetylation of some of the antioxidant enzymes.
  • 845
  • 28 Jul 2020
Topic Review
SIRT1-NF-κB Axis
Inflammation is an adaptive response triggered by harmful conditions or stimuli, such as an infection or tissue damage pursuing homeostasis reestablishment. Liver diseases cause approximately 2 million deaths per year worldwide and hepatic inflammation is a common factor to all of them, being the main driver of hepatic tissue damage and causing progression from NAFLD (non-alcoholic fatty liver disease) to NASH (non-alcoholic steatohepatitis), cirrhosis and, ultimately, HCC (hepatocellular carcinoma). The metabolic sensor SIRT1, a class III histone deacetylase with strong expression in metabolic tissues such as liver, and transcription factor NF-κB, a master regulator of inflammatory response, show an antagonistic relationship in controlling inflammation. For this reason, SIRT1 targeting is emerging as a potential strategy to improve different metabolic and/or inflammatory pathologies. In this review, we explore diverse upstream regulators and some natural/synthetic activators of SIRT1 as possible therapeutic treatment for liver diseases.
  • 1.1K
  • 27 Oct 2020
Topic Review
SIRT1 and SIRT2 Modulators
Depression is a psychiatric disorder that has a significant health burden on patients and their families. Unfortunately, the current antidepressant medications that mainly target monoamine neurotransmitters have limited efficacy. Recent evidence has indicated that neuroinflammation participates in the genesis and development of depression, and interacts with other factors involved in depression. Therefore, exploring effective anti-inflammatory medications could be beneficial for the development of new treatment options for depression. Sirtuins are a unique class of nicotinamide adenine dinucleotide (NAD+)-dependent deacetylases, which have seven members that can affect multiple downstream targets by deacetylation activity.
  • 610
  • 05 Mar 2021
Topic Review
siRNA Structure, Function and Delivery
siRNA is a double-stranded RNA molecule with 21- and 22-nucleotide generated by ribonuclease III cleavage from longer double-stranded RNA (dsRNAs). After binding to the RNA-induced silencing complex (RISC) in the cytoplasm, the sense strand of siRNA undergoes ejection, while the antisense strand of siRNA targets the complementary messenger RNA (mRNA). 
  • 2.1K
  • 20 May 2022
Topic Review
SiRNA and Pancreatic Cancer Therapy
Pancreatic cancer (PC) is one of the leading causes of death and is the fourth most malignant tumor in men. The epigenetic and genetic alterations appear to be responsible for development of PC. Small interfering RNA (siRNA) is a powerful genetic tool that can bind to its target and reduces expression level of a specific gene. The various critical genes involved in PC progression can be effectively targeted using diverse siRNAs. 
  • 480
  • 29 Mar 2022
Topic Review
SiRNA
Short interfering RNAs (siRNAs), also recognized as small RNAi, are double-stranded RNAs with 21–25 nucleotides that are applied to silence target genes in cells. siRNAs are made of two single sequences, named sense strand (passenger strand) and antisense strand (guide strand), connected by an active protein complex called the RNA-Induced Silencing Complex (RISC).
  • 732
  • 18 Dec 2020
Biography
Sir Benjamin Collins Brodie, 1St Baronet
Sir Benjamin Collins Brodie, 1st Baronet, PRS (9 June 1783 – 21 October 1862) was an English physiologist and surgeon who pioneered research into bone and joint disease. Coat of arms of Sir Benjamin Brodie. https://handwiki.org/wiki/index.php?curid=2048995 Brodie was born in Winterslow, Wiltshire. He received his early education from his father, the Rev Peter Bellinger Brodie;
  • 419
  • 06 Dec 2022
Topic Review
SINS
SINS is a newly identified, distinct endogenous syndrome resulting from the combined presence and signs of inflammation and dead tissue in the acral areas. It particularly affects the tail base, tail tip, ears, coronary bands, heels, soles, claw walls, teats, navel, and face and can be observed in suckling piglets, weaners, and finishing pigs.
  • 644
  • 14 Jul 2021
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