Altered DTI scalars in the hippocampus are associated with morphological and structural changes after traumatic brain injury.

Blunt and diffuse injury is a highly prevalent form of traumatic brain injury (TBI) which can result in microstructural alterations in the brain. The blunt impact on the brain can affect the immediate contact region but can also affect the vulnerable regions like hippocampus, leading to functional impairment and long-lasting cognitive deficits. The hippocampus of the moderate weight drop injured male rats was longitudinally assessed for microstructural changes using in vivo MR imaging from 4 h to Day 30 post-injury (PI). The DTI analysis found a prominent decline in the apparent diffusion coefficient (ADC), radial diffusivity (RD), and axial diffusivity (AD) values after injury. The perturbed DTI scalars accompanied histological changes in the hippocampus, wherein both the microglia and astrocytes showed changes in the morphometric parameters at all timepoints. Along with this, the hippocampus showed presence of Aß positive fibrils and neurite plaques after injury. Therefore, this study concludes that TBI can lead to a complex morphological, cellular, and structural alteration in the hippocampus which can be diagnosed using in vivo MR imaging techniques to prevent long-term functional deficits.

Catalyzing a Cure: Discovery and development of LRRK2 inhibitors for the treatment of Parkinson's disease.

Parkinson's disease (PD) is an age-related second most common progressive neurodegenerative disorder that affects millions of people worldwide. Despite decades of research, no effective disease modifying therapeutics have reached clinics for treatment/management of PD. Leucine-rich repeat kinase 2 (LRRK2) which controls membrane trafficking and lysosomal function and its variant LRRK2-G2019S are involved in the development of both familial and sporadic PD. LRRK2, is therefore considered as a legitimate target for the development of therapeutics against PD. During the last decade, efforts have been made to develop effective, safe and selective LRRK2 inhibitors and also our understanding about LRRK2 has progressed. However, there is an urge to learn from the previously designed and reported LRRK2 inhibitors in order to effectively approach designing of new LRRK2 inhibitors. In this review, we have aimed to cover the pre-clinical studies undertaken to develop small molecule LRRK2 inhibitors by screening the patents and other available literature in the last decade. We have highlighted LRRK2 as targets in the progress of PD and subsequently covered detailed design, synthesis and development of diverse scaffolds as LRRK2 inhibitors. Moreover, LRRK2 inhibitors under clinical development has also been discussed. LRRK2 inhibitors seem to be potential targets for future therapeutic interventions in the treatment and management of PD and this review can act as a cynosure for guiding discovery, design, and development of selective and non-toxic LRRK2 inhibitors. Although, there might be challenges in developing effective LRRK2 inhibitors, the opportunity to successfully develop novel therapeutics targeting LRRK2 against PD has never been greater.

Trace elements dyshomeostasis in liver and brain of weanling mice under altered dietary selenium conditions.

BACKGROUND: A balanced diet containing selenium (Se) and other trace elements is essential for normal development and growth. Se has been recognized as an essential trace element; however, its interaction with other elements has not been fully investigated. In the present study, sodium (Na), magnesium (Mg), potassium (K), calcium (Ca), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), copper (Cu), zinc (Zn), Se and rubidium (Rb), were analysed in liver and brain regions under altered dietary Se intake in weanling mice to identify major discriminatory elements. METHODS: The study investigated the effects of different levels of Se intake on the elemental composition in liver and brain tissues of weaned mice. After 24 weeks of feeding with Se adequate, deficient, and excess diets, elemental analysis was performed on the harvested tissues using Inductively coupled plasma mass spectrometry (ICP-MS). Statistical analysis that included analysis of covariance (ANCOVA), correlation coefficient analysis, principal component analysis, and partial least squares discriminant analysis were performed. RESULTS: The ANCOVA showed statistically significant changes and correlations among the analysed elements under altered dietary Se status. The multivariate analysis showed differential changes in elements in liver and brain regions. The results suggest that long-term dietary Se alternations lead to dyshomeostasis in trace elements that are required in higher concentrations compared to Se. It was observed that changes in the Fe, Co, and Rb levels were similar in all the tissues studied, whereas the changes in Mg, Cr, and Mn levels were different among the tissues under altered dietary Se status. Additionally, the changes in Rb levels correlated with the dietary Se intake but had no relation with the tissue Se levels. CONCLUSIONS: The findings suggest interactions between Mg, Cr, Mn, Fe, Co, and Se under altered Se status may impact cellular functions during postnatal development. However, the possible biological significance of alterations in Rb levels under different dietary Se paradigms needs to be further explored.

Anti-Alzheimer activity of new coumarin-based derivatives targeting acetylcholinesterase inhibition.

New 2-oxo-chromene-7-oxymethylene acetohydrazide derivatives 4a-d were designed and synthesized with a variety of bioactive chemical fragments. The newly synthesized compounds were evaluated as acetylcholinesterase (AChE) inhibitors and antioxidant agents in comparison to donepezil and ascorbic acid, respectively. Compound 4c exhibited a promising inhibitory impact with an IC50 value of 0.802 µM and DPPH scavenging activity of 57.14 ± 2.77%. Furthermore, biochemical and haematological studies revealed that compound 4c had no effect on the blood profile, hepatic enzyme levels (AST, ALT, and ALP), or total urea in 4c-treated rats compared to the controls. Moreover, the histopathological studies of 4c-treated rats revealed the normal architecture of the hepatic lobules and renal parenchyma, as well as no histopathological damage in the examined hepatic, kidney, heart, and brain tissues. In addition, an in vivo study investigated the amelioration in the cognitive function of AD-rats treated with 4c through the T-maze and beam balance behavioural tests. Also, 4c detectably ameliorated MDA and GSH, reaching 90.64 and 27.17%, respectively, in comparison to the standard drug (90.64% and 35.03% for MDA and GSH, respectively). The molecular docking study exhibited a good fitting of compound 4c in the active site of the AChE enzyme and a promising safety profile. Compound 4c exhibited a promising anti-Alzheimer's disease efficiency compared to the standard drug donepezil.

Unique mutations in mitochondrial DNA and associated pathways involved in high altitude pulmonary edema susceptibility in Indian lowlanders.

High altitude pulmonary edema (HAPE) is a life threatening non-cardiogenic pulmonary edema that occurs in an otherwise healthy individuals travelling to altitude above 2500 m. Earlier studies have reported association of mutations in nuclear (nDNA) and mitochondrial DNA (mtDNA) with HAPE susceptibility. However, the molecular mechanisms involved in the pathobiology of HAPE have not been fully understood. The present study investigates the genetic predisposition to HAPE by analyzing the mtDNA mutations in HAPE susceptibles (n = 23) and acclimatized controls (n = 23) using next generation sequencing. Structural analysis of mutations was done using SWISS Model server and stability was determined using ΔΔG values. Meta-analysis of GSE52209 dataset was done to identify differentially expressed genes (DEGs) in HAPE susceptibles and acclimatized controls. Fourteen non-synonymous, conserved and pathogenic mutations were predicted using SIFT and PolyPhen scoring in protein coding genes, whereas six mutations in mt-tRNA genes showed association with HAPE (p ≤ 0.05). The structural analysis of these mutations revealed conformational changes in critical regions in Complexes I-V which are involved in subunit assembly and proton pumping activity. The protein-protein interaction network analysis of DEGs showed that HIF1α, EGLN2, EGLN3, PDK1, TFAM, PPARGC1α and NRF1 genes form highly interconnected cluster. Further, pathway enrichment analysis using DAVID revealed that "HIF-1 signaling", "oxidative phosphorylation" and "Metabolic pathways" had strong association with HAPE. Based on the findings it appears that the identified mtDNA mutations may be a potential risk factor in development of HAPE with the associated pathways providing mechanistic insight into the understanding of pathobiology of HAPE and sites for development of therapeutic targets.Communicated by Ramaswamy H. Sarma.

Identification of potential inhibitors of brain-specific CYP46A1 from phytoconstituents in Indian traditional medicinal plants.

Cytochrome P450 46A1 (CYP46A1) is a crucial enzyme in brain that converts cholesterol to 24 (S) hydroxy cholesterol thereby increasing its polarity to facilitate removal of excess cholesterol from the CNS. The inhibition of CYP46A1 with several synthetic molecules has been investigated extensively for treatment of Alzheimer's disease, Huntington's disease, glaucoma, and in hippocampal neurons from aged mice. However, phytochemicals have received far little attention in studies involving development of potential CYP46A1 inhibitors. Thus, in the present study phytoconstituents from Indian traditional medicinal plants; Bacopa monnieri, Piper longum, and Withania somnifera, were virtually screened for interaction with CYP46A1 using computational tools. Out of three plants, six molecules from P. longum and three molecules from W. somnifera were shortlisted to study interactions with CYP46A1 based on the physio-chemical parameters. Fargesin, piperolactam A and coumaperine from P. longum showed the higher binding affinity and the values were - 10.3, - 9.5, - 9.0 kcal/moles respectively, whereas, withaferin A from W. somnifera had a binding affinity of - 12.9 kcal/mol. These were selected as potential modulators as they exhibited suitable interactions with active site residues; Tyr109, Leu112, Trp368, Gly369, and Ala474. The selected molecules were further subjected to molecular dynamics simulation. Further, the pharmacological properties of molecules were also predicted using ADMET calculator and the data revealed that all the selected compounds had good absorption as well as solubility characteristics. In addition, sesamin, fargesin, piperolactam A, and coumaperine had minimal or no toxic effects. Thus, the study successfully identified compounds from Indian medicinal plants that may serve as potential inhibitors of CYP46A1 or base structures to design novel CYP46A1 inhibitors, which may be effective in treating neurological conditions involving perturbed cholesterol homeostasis. Supplementary Information: The online version contains supplementary material available at 10.1007/s42485-022-00098-x.

Structure-based virtual screening for identification of potential non-steroidal LXR modulators against neurodegenerative conditions.

Liver X Receptors (LXRs) are members of the nuclear receptor superfamily that regulate cholesterol metabolism. LXRs have been suggested as promising targets against many neurodegenerative diseases (NDDs). The present study was aimed to identify novel non-steroidal molecules that may potentially modulate LXR activity. The structure-based virtual screening (SBVS) was used to search for suitable compounds from the Asinex library. The top hits were selected and filtered based on their binding affinity for LXR α and ß isoforms. Based on molecular docking and scoring results, 24 compounds were selected that had binding energy in the range of - 13.9 to - 12 for LXRα and - 12.5 to - 11 for LXRß, which were higher than the reference ligands (GW3965 and TO901317). Further, the five hits referred to as model 29, 64, 202, 250, 313 were selected by virtue of their binding interactions with amino acid residues at the active site of LXRs. The selected hits were then subjected to absorption, distribution, metabolism, excretion, and toxicity (ADMET) analysis and blood-brain permeability prediction. It was observed that the selected hits had better pharmacokinetic properties with no toxicity and could cross blood-brain barrier. Further, the selected hits were analysed for dynamic evolution of the system with LXRs by molecular dynamics (MD) simulation at 100 ns using GROMACS. The MD simulation results validated that selected hits possess a remarkable amount of flexibility, stability, compactness, binding energy and exhibited limited conformational modification. The root mean square deviation (RMSD) values of the top-scoring hits complexed with LXRα and LXRß were 0.05-0.6 nm and 0.05-0.45 nm respectively, which is greater than the protein itself. Altogether the study identified potential non-steroidal LXR modulators that appear to be effective against various neurodegenerative conditions involving perturbed cholesterol and lipid homeostasis.

Amifostine analog, DRDE-30, alleviates radiation induced lung damage by attenuating inflammation and fibrosis.

BACKGROUND: Radiotherapy of thoracic neoplasms and accidental radiation exposure often results in pneumonitis and fibrosis of lungs. Here, we investigated the potential of amifostine analogs: DRDE-07, DRDE-30, and DRDE-35, in alleviating radiation-induced lung damage. METHODS: C57BL/6 mice were exposed to 13.5 Gy thoracic irradiation, 30 min after intraperitoneal administration of the analogs, and assessed for modulation of the pathological response at 12 and 24 weeks. KEY FINDINGS: DRDE-07, DRDE-30 and DRDE-35 increased the survival of irradiated mice from 20% to 30%, 80% and 70% respectively. Reduced parenchymal opacity (X-ray CT) in the lungs of DRDE-30 pre-treated mice corroborated well with the significant decrease in Ashcroft score (p < 0.01). Two-fold increase in SOD and catalase activities (p < 0.05), coupled with a 50% increase in GSH content and a 60% decrease in MDA content (p < 0.05) suggested restoration of the antioxidant defence system. A 20% to 40% decrease in radiation-induced apoptotic and mitotic death in the lung tissue (micronuclei: p < 0.01), resulted in attenuated lung and vascular permeability (FITC-Dextran leakage) by 50% (p < 0.01), and a commensurate reduction (~50%) in leukocyte infiltration in the injured tissue (p < 0.05). DRDE-30 abrogated the activation of pro-inflammatory NF-κB and p38/MAPK signaling cascades, suppressing the release of pro-inflammatory cytokines (IL-1ß: p < 0.05; TNF-α: p < 0.05; IL-6: p < 0.05) and up-regulation of CAMs on the endothelial cell surface. Reduction in hydroxyproline content (p < 0.01) and collagen suggested inhibition of lung fibrosis which was associated with attenuation of TGF-ß/Smad pathway-mediated-EMT. CONCLUSION: DRDE-30 could be a potential prophylactic agent against radiation-induced lung injury.

S-nitrosoglutathione alleviates hyperglycemia-induced neurobehavioral deficits involving nitro-oxidative stress and aberrant monaminergic system.

The present study evaluated the protective role of S-nitrosoglutathione (GSNO) in preventing hyperglycemia-induced nitro-oxidative stress and alterations in monoaminergic system associated with neurobehavioral deficits in mice. Mice were subjected to diabetes by intraperitoneal injection of streptozotocin (40 mg/kg body weight) for 5 days, whereas GSNO (100 µg/kg body weight) was administered daily via oral route for 8 weeks. Diabetic mice showed deficits in neurobehavioral functions associated with memory, learning, anxiety and motor coordination. These neurobehavioral deficits observed in diabetic mice may be attributed to decrease in norepinephrine (NE), dopamine (DA), serotonin (5-HT) and increased monoamine oxidase (MAO) activity in cortex and hippocampus. Further, a significant increase in reactive oxygen species (ROS), protein carbonyls, nitrotyrosine (NT) and lipid peroxidation were observed in brain regions of diabetic animals suggesting increased nitro-oxidative stress. Hyperglycemia induced nitro-oxidative stress appears to involve reduction in redox ratio (GSH/GSSG) and enzymatic antioxidants; catalase (CAT) and superoxide dismutase (SOD) in cortex and hippocampus. However, GSNO supplementation was able to ameliorate alterations in monoaminergic system and nitro-oxidative stress in the brain regions thereby restoring neurobehavioural functions. These findings suggest GSNO as potential therapeutic molecule to prevent diabetic encephalopathy.

Garcinol blocks motor behavioural deficits by providing dopaminergic neuroprotection in MPTP mouse model of Parkinson's disease: involvement of anti-inflammatory response.

Although the etiology of Parkinson's disease (PD) is poorly understood, studies in animal models revealed loss of dopamine and the dopaminergic neurons harbouring the neurotransmitter to be the principal cause behind this neuro-motor disorder. Neuroinflammation with glial cell activation is suggested to play a significant role in dopaminergic neurodegeneration. Several biomolecules have been reported to confer dopaminergic neuroprotection in different animal models of PD, owing to their anti-inflammatory potentials. Garcinol is a tri-isoprenylated benzophenone isolated from Garcinia sp. and accumulating evidences suggest that this molecule could provide neuroprotection by modulating oxidative stress and inflammation. However, direct evidence of dopaminergic neuroprotection by garcinol in the pre-clinical model of PD is not yet reported. The present study aims to investigate whether administration of garcinol in the MPTP mouse model of PD may ameliorate the cardinal motor behavioural deficits and prevent the loss of dopaminergic neurons. As expected, garcinol blocked the parkinsonian motor behavioural deficits which include akinesia, catalepsy, and rearing anomalies in the mice model. Most importantly, the degeneration of dopaminergic cell bodies in the substantia nigra region was significantly prevented by garcinol. Furthermore, garcinol reduced the inflammatory marker, glial fibrillary acidic protein, in the substantia nigra region. Since glial hyperactivation-mediated inflammation is inevitably associated with the loss of dopaminergic neurons, our study suggests the anti-inflammatory role of garcinol in facilitating dopaminergic neuroprotection in PD mice. Hence, in the light of the present study, it is suggested that garcinol is an effective anti-parkinsonian agent to block motor behavioural deficits and dopaminergic neurodegeneration in PD.

Targeting SARS-CoV-2 main protease: structure based virtual screening, in silico ADMET studies and molecular dynamics simulation for identification of potential inhibitors.

COVID-19 pandemic has created a healthcare crisis across the world and has put human life under life-threatening circumstances. The recent discovery of the crystallized structure of the main protease (Mpro) from SARS-CoV-2 has provided an opportunity for utilizing computational tools as an effective method for drug discovery. Targeting viral replication has remained an effective strategy for drug development. Mpro of SARS-COV-2 is the key protein in viral replication as it is involved in the processing of polyproteins to various structural and nonstructural proteins. Thus, Mpro represents a key target for the inhibition of viral replication specifically for SARS-CoV-2. We have used a virtual screening strategy by targeting Mpro against a library of commercially available compounds to identify potential inhibitors. After initial identification of hits by molecular docking-based virtual screening further MM/GBSA, predictive ADME analysis, and molecular dynamics simulation were performed. The virtual screening resulted in the identification of twenty-five top scoring structurally diverse hits that have free energy of binding (ΔG) values in the range of -26-06 (for compound AO-854/10413043) to -59.81 Kcal/mol (for compound 329/06315047). Moreover, the top-scoring hits have favorable AMDE properties as calculated using in silico algorithms. Additionally, the molecular dynamics simulation revealed the stable nature of protein-ligand interaction and provided information about the amino acid residues involved in binding. Overall, this study led to the identification of potential SARS-CoV-2 Mpro hit compounds with favorable pharmacokinetic properties. We believe that the outcome of this study can help to develop novel Mpro inhibitors to tackle this pandemic.Communicated by Ramaswamy H. Sarma.

Hydrogen sulfide attenuates hyperhomocysteinemia-induced blood-brain barrier permeability by inhibiting MMP-9.

Backgroud: Hyperhomocysteinemia (HHcy) is implicated in various neurovascular disorders including vascular dementia, subarachnoid hemorrhage and stroke. Elevated homocysteine (Hcy) levels are associated with increased oxidative stress and compromised blood-brain barrier (BBB) integrity. Hydrogen sulfide (H2S) has recently emerged as potent neuroprotective molecule in various neurological conditions including those associated with HHcy. The present study evaluates the protective effect of sodium hydrogen sulfide (NaHS; a source of H2S) on HHcy-induced BBB dysfunction and underpin molecular mechanisms.Materials and methods: Supplementation of NaHS restored the increased BBB permeability in the cortex and hippocampus of HHcy animals assessed in terms of diffused sodium fluorescein and Evans blue tracer dyes in the brain. Activity of matrix metalloproteinases (MMPs) assessed by gelatinase activity and in situ gelatinase assay was restored to the normal in the cortex and hippocampus of HHcy animals supplemented with NaHS.Results: Application of gelatin zymography revealed that specifically MMP-9 activity was increased in the cortex and hippocampus of HHcy animals, which was inhibited by NaHS supplementation. Real-time RT-PCR analysis showed that NaHS administration also decreased mRNA expression of MMP-9 in the hippocampus of HHcy animals. NaHS supplementation was further observed to reduce water retention in the brain regions of Hcy treated animals.Conclusion: Taken together, these findings suggest that NaHS supplementation ameliorates HHcy-induced BBB permeability and brain edema by inhibiting the mRNA expression and activity of MMP-9. Therefore, H2S and H2S releasing drugs may be used as a novel therapeutic approach to treat HHcy-associated neurovascular disorders.

siRNA Mediated GSK3ß Knockdown Targets Insulin Signaling Pathway and Rescues Alzheimer's Disease Pathology: Evidence from In Vitro and In Vivo Studies.

Sporadic Alzheimer's disease (sAD) is a progressive neurodegenerative disorder with dysfunctional insulin signaling and energy metabolism. Emerging evidence suggests impairments in brain insulin responsiveness, glucose utilization, and energy metabolism may be major causes of amyloid precursor protein mishandling. The support for this notion comes from the studies wherein streptozotocin (STZ) induced brain insulin resistance in rodent model resulted in sAD-like neuropathology with cognitive decline. Our previous study showed a compromised insulin signaling pathway, glucose uptake, glucose metabolism, and energy homeostasis in STZ-induced glial-neuronal coculture and in vivo model of sAD. Various components of insulin signaling pathway were examined to understand the metabolic correlation, and GSK3ß was selected for gene knockdown strategy to reverse sAD pathology based on the data. In the present study, we have synthesized carboxylated graphene oxide (GO) nanosheets functionalized with PEG and subsequently with polyethylenimine (PEI) to provide attachment sites for GSK3ß siRNA. Our results showed that siRNA mediated knockdown of the GSK3ß gene reduced expression of amyloid pathway genes (APP and BACE1), which was further confirmed by reduced amyloid beta (Aß) levels in the in vitro STZ-induced sAD model. GSK3ß knockdown also restored insulin signaling, AMPK and Mapk3 pathway by restoring the expression of corresponding candidate genes in these pathways (IR, Glut1/3, Prkaa1/2, Mapk3, BDNF) that reflected improved cellular energy homeostasis, neuronal proliferation, differentiation, maturation, and repair. Behavioral data from Morris water maze (MWM), open field (OF), novel object recognition (NOR), Y maze, and radial arm maze (RAM) tests showed that 0.5 µg nanoformulation (GOc-PP-siRNAGSK3ß) intranasally for 7 days improved spatial memory, rescued anxiety like behavior, improved visual and working memory, and rescued exploratory behavior in STZ-induced sAD rats. GSK3ß silencing resulted in decreased BACE1 expression and prevented accumulation of Aß in the cortex and hippocampus. These molecular findings with improved behavioral performances were further correlated with reduced amyloid beta (Aß) and neurofibrillary tangle (NFTs) formation in the cortex and hippocampus of GOc-PP-siRNAGSK3ß administered sAD rats. Therefore, it is conceivable from the present study that nanoparticle-mediated targeting of GSK3ß in the sAD appears to be a promising strategy to reverse sAD pathology.

Impaired mitochondrial functions and energy metabolism in MPTP-induced Parkinson's disease: comparison of mice strains and dose regimens.

Heterogenous diseases such as Parkinson's disease (PD) needs an efficient animal model to enhance understanding of the underlying mechanisms and to develop therapeutics. MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine), a neurotoxin, has been widely used to replicate the pathophysiology of PD in rodents, however, the knowledge about its effects on energy metabolism is limited. Moreover, susceptibility to different dose regimens of MPTP also varies among mice strains. Thus, the present study compares the effect of acute and sub-acute MPTP administration on mitochondrial functions in C57BL/6 and BALB/c mice. In addition, activity of enzymes involved in energy metabolism was also studied along with behavioural alterations. The findings show that acute dose of MPTP in C57BL/6 mice had more profound effect on the activity of electron transport chain complexes. Further, the activity of MAO-B was increased following acute and sub-acute MPTP administration in C57BL/6 mice. However, no significant change was observed in BALB/c mice. Acute MPTP treatment resulted in decreased mitochondrial membrane potential along with increased swelling of mitochondria in C57BL/6 mice. In addition, perturbations were observed in hexokinase, the rate limiting enzyme of glycolysis and pyruvate dehydrogenase, the enzymes that connects glycolysis and TCA cycle. The activity of TCA cycle enzymes; citrate synthase, aconitase, isocitrate dehydrogenase and fumarase were also altered following MPTP intoxication. Furthermore, acute MPTP administration led to drastic reduction in dopamine levels in striatum of C57BL/6 as compared to BALB/c mice. Behavioral tests such as open field, narrow beam walk and footprint analysis revealed severe impairment in locomotor activity in C57BL/6 mice. These results clearly demonstrate that C57BL/6 strain is more vulnerable to MPTP-induced mitochondrial dysfunctions, perturbations in energy metabolism and motor defects as compared to BALB/c strain. Thus, the findings suggest that the dose and strain of mice need to be considered for pre-clinical studies using MPTP-induced model of Parkinson's disease.

Hydroxytyrosol as anti-parkinsonian molecule: Assessment using in-silico and MPTP-induced Parkinson's disease model.

3-Hydroxytyrosol (HXT) is a natural polyphenol present in extra virgin olive oil. It is a key component of Mediterranean diet and is known for its strong antioxidant activity. The present study evaluated the potential of HXT as an anti-parkinsonian molecule in terms of its ability to inhibit MAO-B and thereby maintaining dopamine (DA) levels in Parkinson's disease (PD). In-silico molecular docking study followed by MMGBSA binding free energy calculation revealed that HXT has a strong binding affinity for MAO-B in comparison to MAO-A. Moreover, rasagiline and HXT interacted with the similar binding sites and modes of interactions. Additionally, molecular dynamics simulation studies revealed stable nature of HXT-MAO-B interaction and also provided information about the amino acid residues involved in binding. Moreover, in vitro studies revealed that HXT inhibited MAO-B in human platelets with IC50 value of 7.78 µM. In vivo studies using MPTP-induced mouse model of PD revealed increase in DA levels with concomitant decrease in DA metabolites (DOPAC and HVA) on HXT treatment. Furthermore, MAO-B activity was also inhibited on HXT administration to PD mice. In addition, HXT treatment prevented MPTP-induced loss of DA neurons in substantia nigra and their nerve terminals in the striatum. HXT also attenuated motor impairments in PD mice assessed by catalepsy bar, narrow beam walk and open field tests. Thus, the present findings reveal HXT as a potential inhibitor of MAO-B, which may be used as a lead molecule for the development of therapeutics for PD.

Effect of hepcidin antagonists on anemia during inflammatory disorders.

Iron is an essential element for the mammalian body however, its homeostasis must be regulated accurately for appropriate physiological functioning. Alterations in physiological iron levels can lead to moderate to severe iron disorders like chronic and acute iron deficiency (anemia) or iron overload. Hepcidin plays an important role in regulating homeostasis between circulating iron and stored iron in the cells as well as the absorption of dietary iron in the intestine. Inflammatory disorders restrict iron absorption from food due to increased circulating levels of hepcidin. Increased production of hepcidin causes ubiquitination of ferroportin (FPN) leading to its degradation, thereby retaining iron in the spleen, duodenal enterocytes, macrophages, and hepatocytes. Hepcidin inhibitors and antagonists play a consequential role to ameliorate inflammation-associated anemia. Many natural and synthesized compounds, able to reduce hepcidin expression during inflammation have been identified in recent years. Few of which are currently at various phases of clinical trial. This article comprises a comprehensive review of therapeutic approaches for the efficient treatment of anemia associated with inflammation. Many strategies have been developed targeting the hepcidin-FPN axis to rectify iron disorders. Hepcidin modulation with siRNAs, antibodies, chemical compounds, and plant extracts provides new insights for developing advanced therapeutics for iron-related disorders. Hepcidin antagonist's treatment has a high potential to improve iron status in patients with iron disorders, but their clinical success needs further recognition along with the identification and application of new therapeutic approaches.

Mitochondrial DNA mutations contribute to high altitude pulmonary edema via increased oxidative stress and metabolic reprogramming during hypobaric hypoxia.

High altitude pulmonary edema (HAPE) is experienced by non-acclimatized sea level individuals on exposure to high altitude hypoxic conditions. Available evidence suggests that genetic factors and perturbed mitochondrial redox status may play an important role in HAPE pathophysiology. However, the precise mechanism has not been fully understood. In the present study, sequencing of mitochondrial DNA (mtDNA) from HAPE subjects and acclimatized controls was performed to identify pathogenic mutations and to determine their role in HAPE. Hypobaric hypoxia induced oxidative stress and metabolic alterations were also assessed in HAPE subjects. mtDNA copy number, mitochondrial oxidative phosphorylation (mtOXPHOS) activity, mitochondrial biogenesis were measured to determine mitochondrial functions. The data revealed that the mutations in Complex I genes affects the secondary structure of protein in HAPE subjects. Further, increased oxidative stress during hypobaric hypoxia, reduced mitochondrial biogenesis and mtOXPHOS activity induced metabolic reprogramming appears to contribute to mitochondrial dysfunctions in HAPE individuals. Haplogroup analysis suggests that mtDNA haplogroup H2a2a1 has potential contribution in the pathobiology of HAPE in lowlanders. This study also suggests contribution of altered mitochondrial functions in HAPE susceptibility.

Potential benefits of phytochemicals from Azadirachta indica against neurological disorders.

Azadirachta indica or Neem has been extensively used in the Indian traditional medical system because of its broad range of medicinal properties. Neem contains many chemically diverse and structurally complex phytochemicals such as limonoids, flavonoids, phenols, catechins, gallic acid, polyphenols, nimbins. These phytochemicals possess vast array of therapeutic activities that include anti-feedant, anti-viral, anti-malarial, anti-bacterial, anti-cancer properties. In recent years, many phytochemicals from Neem have been shown to be beneficial against various neurological disorders like Alzheimer's and Parkinson's disease, mood disorders, ischemic-reperfusion injury. The neuroprotective effects of the phytochemicals from Neem are primarily mediated by their anti-oxidant, anti-inflammatory and anti-apoptotic activities along with their ability to modulate signaling pathways. However, extensive studies are still required to fully understand the molecular mechanisms involved in neuropotective effects of phytochemicals from Neem. This review is an attempt to cover the neuroprotective properties of various phytochemicals from Neem along with their mechanism of action so that the potential of the compounds could be realized to reduce the burden of neurodegenerative diseases.