Receptors & Clinical Investigation (E-Journal - Smart Science & Technology)
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The role of leptin in the central nervous system remyelination
Leptin is identified as a mouse obesity gene, which is also preserved in humans. Leptin receptor is highly expressed in the hypothalamus relative to other tissues; therefore, the function of leptin is mainly attributed to hypothalamic control of food intake and body weight. Although the expression of leptin receptors is not limited to the hypothalamus but is also present in other regions of the central nervous system (CNS), such as the spinal cord, the functions of leptin and leptin receptor in the CNS have not been fully clarified. In this research highlight, we focus on the novel function of leptin in CNS remyelination in pathologic conditions, such as the demyelination mouse model. Because remyelination is a crucial process for repair of neuronal networks after injury and wound healing, knowledge of the underlying molecular mechanism of remyelination is useful to establish a therapeutic strategy against demyelinating diseases. We only revealed the role of leptin in remyelination at a histological level; however, a behavioral analysis and evidence of the beneficial effect of leptin for humans may add to knowledge of the effect of leptin on remyelination function
Melatonin Receptor 1A (MTNR1A) gene sequence characterization and SNP identification in Tropical sheep breeds of India
Sheep is considered to be short day seasonal breeder. Sheep does show varying behavior in terms of seasonal reproduction between temperate and tropical latitudinal regions. MTNR1A gene has been studied widely for being linked to seasonality in sheep. Recently, through our studies we have characterized the MTNR1A gene in Tropical arid sheep breeds and could find out that the GG and CC genotypes are having higher prevalence in the tropical arid breed populationwith reference to two SNP markers ‘ ‘G612A’ and C606T’ respectively
CD28 family of receptors inter-connect in the regulation of T-cells
T-cell activation is mediated by a combination of signals from the antigen receptor (TCR) and co-receptors such as CD28, cytotoxic T-lymphocyte antigen-4 (CTLA-4), programmed cell death antigen 1 (PD-1), CD28H and others. Each is a member of the CD28 receptor gene family. CD28 sends positive signals that promote T-cell responses, while CTLA-4 and PD-1 limit responses. It is the balance between these positive and negative signals that determines the amplitude and level of T-cell responses. The regulatory role of other family members is also becoming the focus of increasing interest. The function of certain CD28 family members such as CTLA-4 and PD-1 is dependent the expression of CD28. Together, these findings have important implications in generation of immune responses and the application of anti-receptor blocking reagents in immunotherapy
Prostate Cancer Metastatic to Bone has Higher Expression of the Calcium-Sensing Receptor (CaSR) than Primary Prostate Cancer
The calcium-sensing receptor (CaSR) is the principal regulator of the secretion of parathyroid hormone and plays key roles in extracellular calcium (Ca2+o) homeostasis. It is also thought to participate in the development of cancer, especially bony metastases of breast and prostate cancer. However, the expression of CaSR has not been systematically analyzed in prostate cancer from patients with or without bony metastases. By comparing human prostate cancer tissue sections in microarrays, we found that the CaSR was expressed in both normal prostate and primary prostate cancer as assessed by immunohistochemistry (IHC). We used two methods to analyze the expression level of CaSR. One was the pathological score read by a pathologist, the other was the positivity% obtained from the Aperio positive pixel count algorithm. Both of the methods gave consistent results. Metastatic prostate cancer tissue obtained from bone had higher CaSR expression than primary prostate cancer (P <0.05). The expression of CaSR in primary prostate cancers of patients with metastases to tissues other than bone was not different from that in primary prostate cancer of patients with or without bony metastases (P >0.05). The expression of CaSR in cancer tissue was not associated with the stage or status of differentiation of the cancer. These results suggest that CaSR may have a role in promoting bony metastasis of prostate cancer, hence raising the possibility of reducing the risk of such metastases with CaSR-based therapeutics
20 Years Anniversary for SORLA/SORL1
SORLA is a sorting receptor known to control the intracellular trafficking of the amyloid precursor protein, which impaired pathway has a central role in the development of Alzheimer’s disease (AD). Recently, genetic analyses confirmed the casual role for SORLA in AD, as coding variants and single nucleotide polymorphisms of SORL1 (gene encoding SORLA) were identified in individuals affected by early-onset AD and late-onset AD, respectively. However, many other different types of ligands were found to target the receptor, thus strongly indicating that SORLA can exert multifunctional activities. In the current review, we provide an overview of the multi-ligand properties of SORLA, showing how this complex receptor is involved in a variety of biological functions
Computational analysis in Influenza virus
Influenza viruses are major human pathogens accountable for respiratory diseases affecting millions of people worldwide and characterized by high morbidity and significant mortality. Influenza infections can be controlled by vaccination and antiviral drugs. However, vaccines need yearly updating and give limited protection. In addition, the currently available drugs suffer from the rapid and extensive emergence of drug resistance. All this highlights the urgent need for developing new antiviral strategies with novel mechanisms of action and with reduced drug resistance potential. Recent advances in the understanding of Influenza virus replication have discovered a number of cellular drug targets that counteract viral drug resistance. With expanded bioinformatics’ knowledge on computational modeling and molecular dynamic stimulations, novel small molecule inhibitors of herbal/ayurvedic origin are being explored due to their non-toxicity and affordability. Using in-silico techniques the structural details and information of influenza protein have been studied to identify the potential drugs for inhibition. Further, we have discussed the various computational studies carried out on major protein/targets of Influenza which could provide new clues for a newer class of antiviral (ayurvedic) drugs. In the years to come ahead, the influenza treatment will go through major changes, with advancing our knowledge of pathogenesis as new methods becoming clinically validated
Targeting sympathetic glia for treating cardiovascular diseases
Gq G protein-coupled receptor (Gq-GPCR) signaling in glial fibrillary acidic protein-expressing (GFAP+) glia is essential for neuron-glia interaction in the Central Nervous System (CNS). However, the exploration of the roles of Gq-GPCR signaling in peripheral GFAP+ glia has just begun. Our recent study showed that GFAP+ glia in the sympathetic ganglia, namely satellite glial cells (SGCs), positively modulate sympathetic-regulated cardiac functions following their Gq-GPCR activation. In this research highlight, we discuss the significance of satellite glial modulation of sympathetic nerve activity (SNA) in both physiology and in diseases. We also present a new experimental strategy for manipulating satellite glial signaling in the sympathetic ganglia using adeno-associated virus (AAV). The success of targeted viral transduction in ganglionic SGCs suggest a strong therapeutic potential of targeting sympathetic glia for the treatment of cardiovascular diseases (CVDs)
HIF-1? promotes NSCs migration by modulating Slit2-Robo1 signaling after cerebral ischemia
Our previous studies have shown that transplantation of Hypoxia-inducible factor-1? (HIF-1?) gene modified neural stem cells (NSCs) reduced brain injury by improving the survival of NSCs and protecting the vascular system. HIF-1? plays pivotal roles during hypoxia, and its downstream pathways might be the primary mechanisms for the growth of NSCs. However, there are very few studies reported whether HIF-1? regulates NSCs migration. In this study, to test the hypothesis that HIF-1? modulates migration of NSCs after cerebral ischemia, we compared the injection of HIF-1? gene recombinant adenovirus, and control adenovirus in ischemia penumbra at 24 h after transient middle cerebral artery occlusion (tMCAO). BrdU labeled NSCs were transplanted in the lateral ventricle at the same time in both groups. The modified neurological severity score (NSS) was used to evaluate neurological deficits. Immunohistochemistry for HIF-1?, BrdU, Slit2 and Robo1 were performed. Comparing with vehicle group HIF-1? group showed better behavioral recovery on day 21 and 28. Expression of HIF-1? in HIF-1? group is higher than that in vehicle group. In HIF-1? group, more BrdU-positive cells were found than that in vehicle group. There are increased Slit2 in HIF-1? group. However, robo1, a receptor of Slits is decreased than that in vehicle group. Thus, we concluded that in cerebral ischemia rat model HIF-1? increased NSCs migration by inhibiting Slit2-Robo1 pathway, and improved the neurological behavior. In conclusion, our results indicate that HIF-1? may be a potential therapeutic target for ischemic stroke through promoting neuroregeneration
Bacterial superantigen toxins induce a lethal cytokine storm by enhancing B7-2/CD28 costimulatory receptor engagement, a critical immune checkpoint
Formation of the costimulatory axis between the B7-2 and CD28 coreceptors is critical for T-cell activation. Superantigens, Gram-positive bacterial virulence factors, cause toxic shock and sepsis by hyperinducing inflammatory cytokines. We report a novel role for costimulatory receptors CD28 and B7-2 as obligatory receptors for superantigens, rendering them therapeutic targets. We show that by engaging not only CD28 but also its coligand B7-2 directly, superantigens potently enhance the interaction between B7-2 and CD28, inducing thereby T-cell hyperactivation. Using a conserved twelve amino-acid domain, superantigens engage both B7-2 and CD28 at their homodimer interfaces, sites far removed from where these receptors interact, implying that inflammatory signaling can be controlled through the receptor homodimer interfaces. Short B7-2 and CD28 dimer interface mimetic peptides bind diverse superantigens, prevent superantigen binding to cell-surface B7-2 or CD28, attenuate inflammatory cytokine overexpression, and protect mice from lethal superantigen challenge. Thus, superantigens induce a cytokine storm by mediating not only the interaction between MHC-II molecule and T-cell receptor but critically, by promoting B7-2/CD28 coreceptor engagement, forcing the principal costimulatory axis to signal excessively. Our findings highlight the B7/CD28 interaction as a bottleneck in signaling for expression of inflammatory cytokines. B7-2 and CD28 homodimer interface mimetic peptides prevent superantigen lethality by blocking the superantigen-host costimulatory receptor interaction
Urokinase-type plasminogen activator (uPA) and its receptor (uPAR) promote neurorepair in the ischemic brain
Despite the fact that ischemic stroke has been considered a leading cause of mortality in the world, recent advances in our understanding of the pathophysiological mechanisms underlying the ischemic injury and the treatment of acute ischemic stroke patients have led to a sharp decrease in the number of stroke deaths. However, this decrease in stroke mortality has also led to an increase in the number of patients that survive the acute ischemic injury with different degrees of disability. Unfortunately, to this date we do not have an effective therapeutic strategy to promote neurological recovery in these growing population of stroke survivors. Cerebral ischemia not only causes the destruction of a large number of axons and synapses but also activates endogenous mechanisms that promote the recovery of those neurons that survive its harmful effects. Here we review experimental evidence indicating that one of these mechanisms of repair is the binding of the serine proteinase urokinase-type plasminogen activator (uPA) to its receptor (uPAR) in the growth cones of injured axons. Indeed, the binding of uPA to uPAR in the periphery of growth cones of injured axons induces the recruitment of ?1-integrin to the plasma membrane, ?1-integrin-mediated activation of the small Rho GTPase Rac1, and Rac1-induced axonal regeneration. Furthermore, we found that this process is modulated by the low density lipoprotein receptor-related protein (LRP1). The data reviewed here indicate that the uPA-uPAR-LRP1 system is a potential target for the development of therapeutic strategies to promote neurological recovery in acute ischemic stroke patients