Journey of Teplizumab: A Promising Drug in the Treatment of Type 1 Diabetes Mellitus.

Type 1 diabetes (T1D) is a chronic autoimmune disease caused by CD4+ and CD8+ that are activated via CD3+ cells and finally lead to the macrophages destroying the beta cells in the pancreas thereby causing diabetes. The anti-CD3 humanized monoclonal antibody was approved on 17th November 2022 by the United States Food Drug Administration (USFDA) with the name teplizumab and the brand name TZIELD. This is the only approved drug that treats type 1 diabetes (T1D) by delaying the onset of stage 3 in type 1 diabetes (T1D). This review outlines essential features of teplizumab including its brief introduction to its mechanism and other therapies for the treatment and various risks as well as the pharmacokinetics and pharmacodynamics of this disease and the clinical trial reports for the completed and ongoing therapies.

Current Trends of Analytical Techniques for Bioactive Terpenoids: A Review.

Terpenes and terpenoids are the primary bioactive substances present in essential volatile oils, condensed liquids extracted from diverse plant parts. These substances demonstrate remarkable biological activity and are frequently used as medicines, food additives, and scent molecules. Terpenoids have a wide range of pharmacological effects on the human body, including the treatment, prevent, and reduce the discomfort associated with a number of chronic illnesses. Therefore, these bioactive substances are crucial to our everyday existence. As most terpenoids are present in complex form, coupled with many other raw plant elements, it is important to identify and characterize these molecules. This article addresses various classes of terpenoids, their biochemical processes, and their biological functions. Additionally, it includes a comprehensive description of several hyphenated procedures and recently popular analytical approaches used for isolation, identification, and absolute characterization. It also includes a discussion of the various advantages, drawbacks, and challenges encountered during the collection of the sample and throughout the entire research process.

A multispectroscopic approach for ultra-trace sensing of prostate specific antigen (PSA) by iron nanocomposite fabricated on graphene nanoplatelet.

Herein we report an easy, rapid and cost-effective method for spectroscopic sensing of a prostate cancer biomarker prostate specific antigen (PSA) using a novel nanocomposite. The material is a synthetic quinoxaline derivative-based iron nanocomposite fabricated on graphene nanoplatelet surface (1d-Fe-Gr). Presence of graphene enhanced the efficacy of synthesized 1d-Fe-Gr to sense PSA in serum medium with an impressive limit of detection (LOD) value of 0.878 pg/mL compared to 1d-Fe alone (LOD 17.619 pg/mL) using UV-visible absorption spectroscopy. LOD of PSA by 1d-Fe-Gr using Raman spectroscopy is even more impressive (0.410 pg/mL). Moreover, presence of interfering biomolecules like glucose, cholesterol, bilirubin and insulin in serum improves the detection threshold significantly in presence of 1d-Fe-Gr which otherwise cause LOD values of PSA to elevate in control sets. In presence of these biomolecules, the LOD values improve significantly as compared to healthy conditions in the range 0.623-3.499 pg/mL. Thus, this proposed detection method could also be applied efficiently to the patients suffering from different pathophysiological disorders. These biomolecules may also be added externally during analyses to improve the sensing ability. Fluorescence, Raman and circular dichroism spectroscopy were used to study the underlying mechanism of PSA sensing by 1d-Fe-Gr. Molecular docking studies confirm the selective interaction of 1d-Fe-Gr with PSA over other cancer biomarkers.

Fluorosensing of benzaldehydes by CuI-graphene: A spectroscopy, thermodynamics and docking supported phenomenon.

Benzaldehyde and 4-methyl benzaldehyde constitute a major part of the harmful volatile organic compounds (VOCs) found in the environment. Hence, rapid and selective detection of benzaldehyde derivatives are required to minimize the environmental degradation as well as the potential hazards on human health. In this study, the surface of the graphene nanoplatelets were functionalized with CuI nanoparticles for specific and selective detection of benzaldehyde derivatives by fluorescence spectroscopy. CuI-Gr nanoparticles exhibited higher efficiency towards the detection of benzaldehyde derivatives as compared to pristine CuI nanoparticles with detection limit (LOD) 2 ppm and 6 ppm for benzaldehyde and 4-methyl benzaldehyde respectively in aqueous medium. The LOD values for the detection of benzaldehyde and 4-methyl benzaldehyde by pristine CuI nanoparticles were poor and found to be 11 ppm and 15 ppm respectively. Fluorescence intensity of CuI-Gr nanoparticles were found to be quenched with increasing concentration (0-0.01 mg/mL) of the benzaldehyde and 4-methyl benzaldehyde. This novel graphene-based sensor was also found to be highly selective for the benzaldehyde derivatives as no changes in signal were detected in presence of other VOCs like formaldehyde and acetaldehyde.

Neutron Activation Analysis: An Excellent Nondestructive Analytical Technique for Trace Metal Analysis.

For proper functioning of the human body, several metals are required in different concentrations but if their concentration slightly elevates, because of any metal-contaminated environment or of other food sources, which leads to high toxicity and different chronic health issues. Different analytical techniques like atomic absorption spectroscopy, X-ray fluorescence, inductively coupled plasma- mass spectroscopy (ICP-MS) and flame atomic absorption spectroscopy are used for metals analysis present in different samples in different fields but nowadays neutron activation analysis (NAA) is preferred over other analytical techniques because it is an efficient, multi-elemental, nondestructive analytical technique having an ultralow minimum detection limit, therefore it can detect heavy metals (HMs) even if at a very trace level parts per billion (ppb) with a quite simple sample preparation technique. This technique is known as "referee technique" because of its accuracy and trustworthiness. There is a widespread use of this technique in biomedical science like in Alzheimer's disease, cancer, arthritis, metabolism study, brain tumor and in many more conditions where metals are actively present. For its typical sample sizes and due to a multitude of additional benefits, it also helps in mapping of pathophysiology of the disease. Besides all, mainly in biomedical science the biological samples can easily be analyzed irrespective of any form. In recent years NAA is preferred over other analytical techniques in several research fields, so this article focuses on the analytical technique, its general principle and recent applications.

Heme-Mimetic Potential of Iron Conjugated Pheophytin-I in Attenuating Oxidative Stress-Induced Cellular and Vascular Toxicity.

Purpose of the Study: Heme is the cardinal porphyrin in systemic physiology, apart from hemoglobin it forms structural skeleton of physiological antioxidants such as catalase and peroxidases. Aim: The current study presents evidence that iron chelated pheophytin (Fe-Ph-I) created in resemblance to heme can exert significant heme-mimetic efficacy in mitigating oxidative stress-induced cellular and vascular damage. Materials and Methods: Fe-Ph-I was synthesized by incorporating ferrous ion into the porphyrin core of Ph-I moiety. The candidate drugs (Ph-I and Fe-Ph-I) were characterized by spectroscopic analysis and heme-mimetic attribute of Fe-Ph-I was established by comparing the efficacy of Fe-Ph-I with reference to its unmetallated parent Ph-I as well as un-chelated ferrous ions in a host of in vitro, ex vivo, and in vivo bioassays paradigms. Results: The study confirmed that Fe-Ph-I, Ph-I, and free ferrous ions all exerts significant in vitro anti-radical efficacy, however, while un-chelated ferrous ions intensifies, Ph-I and Fe-Ph-I mitigate ex vivo oxidative stress with Fe-Ph-I exhibiting superior potency. Also from in vivo assessment of oxidative stress-induced hemolytic anemia, it was observed that Fe-Ph-I is significantly superior than Ph-I in alleviating intravascular hemolysis, thereby endorsing that not ferrous ions alone but ferrous ion chelated with porphyrin yielding a heme-mimetic structure is responsible for superior potency of Fe-Ph-I over Ph-I. Conclusion: In conclusion, Fe-Ph-I is cost-effective and therapeutically safe biological macromolecule of clinical potency against pathologies either mediated by or themselves precipitate oxidative stress-induced cellular or vascular damage.

Erythroid spectrin binding modulates peroxidase and catalase activity of heme proteins.

Hemoglobin oxidation due to oxidative stress and disease conditions leads to the generation of ROS (reactive oxygen species) and membrane attachment of hemoglobin in-vivo, where its redox activity leads to peroxidative damage of membrane lipids and proteins. Spectrin, the major component of the red blood cell (RBC) membrane skeleton, is known to interact with hemoglobin and, here this interaction is shown to increase hemoglobin peroxidase activity in the presence of reducing substrate ABTS (2', 2'-Azino-Bis-3-Ethylbenzothiazoline-6-Sulfonic Acid). It is also shown that in the absence of reducing substrate, spectrin forms covalently cross-linked aggregates with hemoglobin which display no peroxidase activity. This may have implications in the clearance of ROS and limiting peroxidative damage. Spectrin is found to modulate the peroxidase activity of different hemoglobin variants like A, E, and S, and of isolated globin chains from each of these variants. This may be of importance in disease states like sickle cell disease and HbE-ß-thalassemia, where increased oxidative damage and free globin subunits are present due to the defects inherent in the hemoglobin variants associated with these diseases. This hypothesis is corroborated by lipid peroxidation experiments. The modulatory role of spectrin is shown to extend to other heme proteins, namely catalase and cytochrome-c. Experiments with free heme and Raman spectroscopy of heme proteins in the presence of spectrin show that structural alterations occur in the heme moiety of the heme proteins on spectrin binding, which may be the structural basis of increased enzyme activity.

Preclusion of methemoglobinemia caused by nitrate drugs in diabetics and nondiabetics: Possible role of Vitamin C.

The drugs containing nitrates like isosorbide dinitrate, isosorbide mononitrate and glyceryl trinitrate, etc., trigger the oxidation of hemoglobin which is manifested in the pathological disorder named methemoglobinemia. It was considered interesting to investigate the preventive roles of vitamin C towards the toxic effects of nitrate containing drugs used for the treatment of angina. The aim is to find whether these drugs need to be administered with special care to diabetic patients who are more prone to develop methemoglobinemia. Vitamin C (500 mg/day) was administered orally to reduce the methemoglobin (metHb) level in both the diabetic and nondiabetic patients consuming nitrate containing drugs regularly, keeping diabetic and nondiabetic patients not on nitrate drugs as control. Concentration of metHb and hemoglobin A (HbA) was estimated spectrophotometrically assuming the molar extinction coefficient values of metHb as 3.78 mM--1 cm--1 at 630 nm and HbA as 125,000 M --1 cm --1 at 415 nm. MetHb level was found to be lower after the treatment with vitamin C for 30 consecutive days than that before the trial with statistically significant two tailed p value. Additionally, fasting insulin level was also found to decrease after 4 weeks of consumption of vitamin C with moderate lowering of fasting serum glucose level as well, indicating a higher insulin sensitivity for the treated patients.

Reduced TREM2 activation in microglia of patients with Alzheimer's disease.

Loss-of-function variants of triggering receptor expressed on myeloid cells 2 (TREM2) increase the risk of developing Alzheimer's disease (AD). The mechanism through which TREM2 contributes to the disease (TREM2 activation vs inactivation) is largely unknown. Here, we analyzed changes in a gene set downstream of TREM2 to determine whether TREM2 signaling is modified by AD progression. We generated an anti-human TREM2 agonistic antibody and defined TREM2 activation in terms of the downstream expression changes induced by this antibody in microglia developed from human induced pluripotent stem cells (iPSC). Differentially expressed genes (DEGs) following TREM2 activation were compared with the gene set extracted from microglial single nuclear RNA sequencing data of patients with AD, using gene set enrichment analysis. We isolated an anti-TREM2-specific agonistic antibody, Hyb87, from anti-human TREM2 antibodies generated using binding and agonism assays, which helped us identify 300 upregulated and 251 downregulated DEGs. Pathway enrichment analysis suggested that TREM2 activation may be associated with Th2-related pathways. TREM2 activation was lower in AD microglia than in microglia from healthy subjects or patients with mild cognitive impairment. TREM2 activation also showed a significant negative correlation with disease progression. Pathway enrichment analysis of DEGs controlled by TREM2 activity indicated that TREM2 activation in AD may lead to anti-apoptotic signaling, immune response, and cytoskeletal changes in the microglia. We showed that TREM2 activation decreases with AD progression, in support of a protective role of TREM2 activation in AD. In addition, the agonistic anti-TREM2 antibody can be used to identify TREM2 activation state in AD microglia.

Effect of organo-selenium anticancer drugs on nitrite induced methemoglobinemia: A spectroscopic study.

Selenium containing drugs like selenomethionine, selenocystine, selenourea and methylseleninic acid are reported to exhibit potential anticancer effect. However, these anticancer drugs may exert adverse effects when used over a prolonged period. Little is known about the interaction of these selenium containing drugs with the vital erythroid protein hemoglobin. In this work a comparative study of the interaction of organo-selenium drugs with hemoglobin and heme moiety has been performed using different spectroscopic techniques to find out their role on drug induced methemoglobinemia. We found that though these selenium containing drugs have similar binding affinity towards hemoglobin, they have differential interactions with the heme group. Isothermal calorimetric titration study showed that selenourea has the lowest binding affinity (Kd 19.28 µM) towards HbA as compared to other drugs, selenomethionine, selenocystine and methylseleninic acid (Kd 7.69 µM, 4.88 µM and 10.5 µM at 37 °C respectively). This result is also supported by the molecular docking study. Methylseleninic acid was found to have detrimental effects on nitrite induced methemoglobinemia, a hematological disorder caused due to excessive conversion of Fe2+ to Fe3+ in hemoglobin. Hence the results of the study would help to develop a better insight on the mechanism of action and anticipate the toxicity of these drugs which require further optimization before their actual use in the treatment of cancer.

Disparity of selenourea and selenocystine on methaemoglobinemia in non-diabetics and diabetics.

Organoselenium drugs like selenourea (SeU) and selenocystine (SeC) are found to exhibit several medicinal properties and have reported roles in the field of cancer prevention. However, studies related to their interactions with the major erythroid protein, haemoglobin (HbA) are still in dearth despite being of prime importance. In view of this, it was considered essential to investigate the interaction of these two anticancer drugs with Hb. Both the drugs showed significant changes in absorption spectra of Hb at wavelength of maximum absorption (λmax) 630 nm. SeU itself had no effect on the absorbance value at 630 nm with respect to time even with 400 µM concentration. However, it was rapidly converted to nanoselenium in presence of nitrite and there was an increase in the absorbance rate at 630 nm from 3.39 × 10-3 min-1 (without nitrite) to 8.94 × 10-3 min-1 in presence of nitrite (200 µM) owing to the generation of reactive oxygen species in the medium. Although the generation and increase in peak intensity at 630 nm in Hb generally indicates the formation and rise in the levels of methaemoglobin (metHb), nanoselenium was observed to follow a different path. Instead of causing oxidation of Fe2+ to Fe3+ responsible for metHb formation, nanoselenium was found to interact with the protein part, thereby causing changes in its secondary structure which is reflected in the increasing absorbance at 630 nm. SeC, however, showed a different effect. It was shown to act as a novel agent to reduce nitrite-induced metHb formation in a dose-dependent manner. The efficiency of SeC was again found to be less in diabetic blood samples as compared to the non-diabetic ones. For similar ratio of metHb to SeC (1:8), % reduction of metHb was found to be 27.46 ± 0.82 and 16.1 ± 2.4 for non-diabetic and diabetic samples, respectively, with a two tailed P-value much <0.05 which implies that the data are highly significant.

Caffeine and catechin towards prevention of drug induced oxidation of hemoglobin: A spectroscopic study.

Administration of low doses of nitrates over prolonged periods in patients suffering from coronary heart disease may lead to chronic methemoglobinemia, a disease caused by oxidation of hemoglobin. Previous reports have shown that natural products like curcumin, vitamin E, vitamin C, resveratrol, etc., are capable of inhibition of nitrite induced oxidation of hemoglobin. Hence in this study we aimed to investigate the preventive role of antioxidants present in our diet, like caffeine and catechin hydrate which are commonly found in coffee and tea towards methemoglobin (met-Hb) formation. Our study revealed that when the hemolysate was pre-incubated with equimolar concentration of caffeine and its metabolite with respect to nitrite, the rate of the nitrite induced oxidation of HbA decreased from (7.33 ± 0.54) × 10-5 min-1 to (7.09 ± 1.05) × 10-5 min-1 and (2.98 ± 0.06) × 10-5 min-1 respectively. Hence it was evident that the metabolite of caffeine, 1-methyluric acid, exhibited better efficiency at physiological concentration than its precursor. On the contrary, only 4 mM catechin hydrate could enhance the rate of methemoglobin formation even in absence of nitrite and the rate of the reaction was (6.088 ± 0.31) × 10-5 min-1 which is comparable with that of 400 µM nitrite.

Bioisosteric Replacement of Amide Group with 1,2,3-Triazoles in Acetaminophen Addresses Reactive Oxygen Species-Mediated Hepatotoxic Insult in Wistar Albino Rats.

Acetaminophen (AP) is a popularly recommended over-the-counter analgesic-antipyretic in clinical use. However, the drug is handicapped by the occurrence of hepatotoxic insult following acute ingestion. Consequently, AP-induced hepatotoxicity is often implicated in accidental or suicidal overdose. In the current study, we investigated the potential of bioisosteric replacement of amide in AP with 1,2,3-triazoles in curbing AP-induced hepatotoxicity. The therapeutic utility of synthesized bioisosteres was established by careful tailoring and optimization of the synthetic methodology along with detailed toxicological testing of pharmacologically potent acetaminophen-triazole derivatives (APTDs). Along the same lines, we herein report a series of 17 novel APTDs synthesized via aromatic substitution using sodium azide, l-proline, and copper iodide followed by click reaction with substituted alkynes using copper sulfate and sodium ascorbate. Pharmacological evaluation of synthesized APTDs revealed that, out of the series of 17 compounds, 5a and 5e were found to be most efficacious in exerting anti-inflammatory, analgesic, and antipyretic activity in an animal model. Further toxicity studies documented that, in both acute and sub-acute toxicology, AP administration caused significant hepatotoxicity, which was found to be a consequence of ROS-mediated oxidative stress. Potent APTDs (5a and 5e), on the other hand, revealed no adverse event in both acute and sub-toxicological analyses. Median lethal dose (LD50) and no observed adverse effect level (NOAEL) values for 5a and 5e were found to be >1000 mg/kg and 2000 mg/kg, respectively. The human equivalent dose, defining the maximum safe concentration of a compound in a human's physiology, was found to be 27.68 mg/kg for the most potent APTDs (5a and 5e). Thus, it can be concluded that triazole incorporation into AP nucleus produced conjugates devoid of hepatotoxic manifestations, having the added advantage of anti-inflammatory efficacy along with analgesic and antipyretic potency.

Correction to: Epigenetic Regulation of SNAP25 Prevents Progressive Glutamate Excitotoxicty in Hypoxic CA3 Neurons.

The original version of this article unfortunately contained mistake.

Electronegativity in Substituted-4(H)-quinazolinones Causes Anxiolysis without a Sedative-hypnotic Adverse Reaction in Female Wistar Rats.

OBJECTIVE: In the current study, the synthesis, characterization, and neuropharmacology of quinazolinone tethered with aromatic (3a-3i) and heteroaromatic substitution (3j, 3k, and 3l) as effective anxiolytic agents are reported. BACKGROUND: Anxiety and depression are often comorbid with neurological as well as other medical maladies. Clinically known anxiolytics (Benzodiazepines) are accompanied by untoward sedation and other CNS depressive actions. The quinazolinone moiety is a privileged pharmacophore with a wide pharmacological spectrum. Herein, the synthesis, characterization, and neuropharmacological evaluation of some 2-substituted quinazolinone derivatives are reported. METHODS: The synthesized compounds were characterized using 1H-NMR and TLC analysis. Behavioral analysis was performed using EPM (Elevated Plus Maze), OFT (Open Field Test), PIST (Pentobarbital Induced Sleep Test), FST (Forced Swim Test) and PCPA (p-chlorophenyl alanine) bioassay. To further justify the therapeutic claim, systemic and neurotoxicological analysis of the most potent members of the series was performed using OECD mandated protocols. The studies showed that the compounds had a wide therapeutic window with >1000 mg/kg and >500 mg/kg LD50 and NOAEL, respectively. RESULTS: The compounds with an electronegative group in the quinazolinone nucleus (3f, 3e, 3d, and 3c) induced anxiolysis devoid of sedative adverse reaction. Besides, anti-depressant efficacy of 3f, 3e, 3d, and 3c observed in rodents was a result of a decrease in anxiety level. It was found that the neurotoxicology of the potent members (3f, 3e, 3d, and 3c) advocated their wide therapeutic window with >1000 mg/kg LD50 and >5000 mg/kg NOAEL. CONCLUSION: Our findings of behavioral bioassays revealed that inducing an electronegative group into the quinazolinone nucleus yielded the most potent members of the series (3f, 3e, 3d, and 3c). The said compounds were found to produce anxiolysis and anti-depressive action without sedative-hypnotic side effects in rodent models. In summary, it can be stated that extending the studies in a clinical setting would furbish the contours of current anxiolytic therapy, especially in anxiety comorbid with medical maladies.

Bio-isosteric replacement of amide group with 1,2,3-triazole in phenacetin improves the toxicology and efficacy of phenacetin-triazole conjugates (PhTCs).

AIM: Inflammatory algesia and pyresia are common pathological consequences of physiological defense. Phenacetin introduced as effective analgesic anti-pyretic agent, was proscribed from therapeutic use because of associated systemic toxicity. The aim of the study was to evaluate the potency of 1,2,3-triazole conjugation in reducing toxicity and increasing efficacy of the phenacetin nucleus. MAIN METHODS: The amide bond implicated as the cause of phenacetin toxicity was bioisosterically replaced with 1,2,3-triazoles to yield a series of PhTCs(PhTC1, PhTC2 and PhTC3). The toxicology of the synthesized conjugates in reference to phenacetin was evaluated in accordance with OECD test guidelines 420, 425 and 407. For the purpose of evaluating anti-inflammatory potency carrageenan induced paw edema and croton oil induced ear edema models were evaluated. Anti-nociceptive efficacy was assessed using Eddy's hot plate and acetic acid induced writhing experimental models. For anti-pyretic efficacy, the conjugates were submitted to Brewer's yeast antipyretic assay. KEY FINDINGS: Toxicological examination of PhTCs in comparison to phenacetin revealed that, phenacetin treatment caused considerable nephrotoxicity and hepatotoxicity in experimental models PhTCs were devoid of such toxic manifestations. Results of pharmacological assays showed that the entire series of PhTCs possessed better anti-inflammatory, anti-nociceptive and anti-pyretic potential than phenacetin. Furthermore it was revealed that the pharmacological profile of PhTC1 with triazole substitution at para position of the phenol ring exhibited potency even better than that exhibited by the reference standards. CONCLUSION: Bioisosteric replacement of amide bond by 1,2,3-triazole in the phenacetin moiety yields conjugates with superior efficacy and diminished toxicity, thus opening neo avenues in treatment of inflammatory syndromes.

Methanolic root extract of Codonopsis clematidea prevents hypoxia induced procoagulant state by inhibition of GPIb receptor regulated Lyn kinase activation.

BACKGROUND: The prevalence of procoagulant state under prolonged hypoxic exposures and the complications and lack of specificity associated with use of existing anti-thrombotic agents have necessitated the search for safer and natural therapeutics. Codonopsis, a widely studied medicinal herb, has been reported to decrease whole blood viscosity but the bioactive ingredients involved, and their mechanism of action therein however remain to be investigated. PURPOSE: The present study aimed at evaluating the efficacy of C. clematidea root extract and mechanism of action of its bioactive constituent flavonoid, Kaempferol, in ameliorating hypobaric hypoxia induced procoagulant state. METHODS: Fingerprinting analysis of methanolic extract of C. clematidea root was performed by RP-HPLC. In vitro toxicity study was conducted using HUVEC cell line and in vivo acute and sub-acute toxicity were done according to OECD guidelines (section-4, number-420 and 407 respectively). Adult male Sprague-Dawley rats weighing 230-250 g were exposed to global hypoxia simulating an altitude of 7600 m (282 mmHg), in animal decompression chamber for 3, 7, 14 and 21 days for in vivo studies. Dose optimisation of the extract was done by quantification of Thromboxane A2 in the serum of hypoxic rats. C. clematidea root extract was also evaluated for its in vitro and in vivo antioxidant properties. Procoagulant changes were studied by biochemical plasma coagulation assays and expression analysis of the signalling molecules of the platelet activation cascade like vWF, platelet activation marker CD41, GpIb-IX-V (CD42), Lyn kinase, p-PI3K, p-ERK and p-PLCγ were conducted to investigate C. clematidea mediated signalling mechanisms. RESULTS: Methanolic extract of C. clematidea root showed improved antioxidant status and improvement in bleeding time and in vitro coagulation assays like pT, aPTT, INR. Decreased concentrations of D-Dimers along with that of platelet activation marker CD41 and serum concentration of Thromboxane A2 were observed in C. clematidea root extract supplemented hypoxic animals. Phosphorylation of Lyn kinase, was reduced despite increase in concentration of activating ligand vWF. CONCLUSION: C. clematidea root extract was effective in preventing hypoxia induced platelet activation and resultant procoagulant state by inhibiting Lyn kinase, a serine threonine kinase effector of vWF signalling cascade.

Kaempferol Inhibits Extra-synaptic NMDAR-Mediated Downregulation of TRkß in Rat Hippocampus During Hypoxia.

Cognitive dysfunction on chronic exposure to hypobaric hypoxia has been attributed to a myriad of survival and degenerative factors. Downregulation of Trkß and compromised survival signaling has been ascribed as a major contributing factor for hypoxic neurodegeneration. The mechanisms leading to downregulation of Trkß in hypoxia, however, remain to be elucidated. The present study aimed at investigating the upstream signaling mechanisms leading to Trkß downregulation in hypoxia and the potential of Kaempferol in ameliorating these changes. Our results showed a duration-dependent increase in hypoxic neurodegeneration as measured by Fluoro-Jade C staining of hippocampal CA3 neurons. Protein expression studies revealed strong correlation of Trkß with NR1 and NR2b expression on exposure to hypoxic stress. Administration of Kaempferol during hypoxic stress revealed its neuroprotective effect and Morris Water Maze test also highlighted its efficacy in improving spatial learning and memory. Further elucidation of the signaling mechanisms using specific inhibitors and in vitro silencing experiments confirmed involvement of extra-synaptic N-methyl-d-aspartate receptor (NMDAR) i.e. NR2b receptor subunit in downregulation of Trkß under hypoxic conditions. ChIP assay showed involvement of E47 transcription factor in NR2b mediated Trkß downregulation. Selective inhibition of signaling intermediate MLK2 by CEP11004 and inhibition of extra-synaptic NMDAR during hypoxic stress prevented Trkß downregulation in the hippocampus of hypoxic rats. Administration of Kaempferol also inhibited phosphorylation of E47 and hypoxia-induced downregulation of Trkß. The present study establishes the role of extra-synaptic NMDAR in hypoxia-induced downregulation of Trkß and the efficacy of Kaempferol in inhibiting extra-synaptic NMDAR-mediated signaling.

Structure-activity relationship of heme and its analogues in membrane damage and inhibition of fusion.

Under pathological conditions, such as sickle cell disease and malaria, heme concentration increases considerably, and it induces membrane damage. As sickled and normal erythrocytes contain high cholesterol: phospholipid ratio, we investigated the role of lipid composition, chain length, and unsaturation on the partitioning and leakage of hemin in phospholipid vesicles. To establish structure-activity relationship in membrane damage, experiments with two other analogues, protoporphyrin-IX and hematoporphyrin (HP) were also carried out. Hemin and its analogues localize differently in membranes and exhibit distinct roles in partitioning, leakage and fusion. Hemin and HP trigger more leakage in the presence of aminophospholipids, whereas cholesterol buffers the destabilizing effect remarkably. Inhibition of fusion by hemin further suggests its unexplored and important role in membrane trafficking, particularly under diseased conditions.