Time-Dependent Potentiation of the PERK Branch of UPR by GPR68 Offers Protection in Brain Ischemia.

BACKGROUND: In ischemia, acidosis occurs in/around injured tissue and parallels disease progression. Therefore, targeting an acid-sensitive receptor offers unique advantages in achieving the spatial and temporal specificity required for therapeutic interventions. We previously demonstrated that increased expression of GPR68 (G protein-coupled receptor 68), a proton-sensitive G protein-coupled receptor, mitigates ischemic brain injury. Here, we investigated the mechanism underlying GPR68-dependent protection. METHODS: We performed biochemical and molecular analyses to examine poststroke signaling. We used in vitro brain slice cultures and in vivo mouse transient middle cerebral artery occlusion (tMCAO) models to investigate ischemia-induced injuries. RESULTS: GPR68 deletion reduced PERK (protein kinase R-like ER kinase) expression in mouse brain. Compared with the wild-type mice, the GPR68-/- (knockout) mice exhibited a faster decline in eIF2α (eukaryotic initiation factor-2α) phosphorylation after tMCAO. Ogerin, a positive modulator of GPR68, stimulated eIF2α phosphorylation at 3 to 6 hours after tMCAO, primarily in the ipsilateral brain tissue. Consistent with the changes in eIF2α phosphorylation, Ogerin enhanced tMCAO-induced reduction in protein synthesis in ipsilateral brain tissue. In organotypic cortical slices, Ogerin reduced pH 6 and oxygen-glucose deprivation-induced neurotoxicity. Following tMCAO, intravenous delivery of Ogerin reduced brain infarction in wild-type but not knockout mice. Coapplication of a PERK inhibitor abolished Ogerin-induced protection. Delayed Ogerin delivery at 5 hours after tMCAO remained protective, and Ogerin has a similar protective effect in females. Correlated with these findings, tMCAO induced GPR68 expression at 6 hours, and Ogerin alters post-tMCAO proinflammatory/anti-inflammatory cytokine/chemokine expression profile. CONCLUSIONS: These data demonstrate that GPR68 potentiation leads to neuroprotection, at least in part, through enhancing PERK-eIF2α activation in ischemic tissue but has little impact on healthy tissue.

Biomacromolecule-Assisted Screening for Reaction Discovery and Catalyst Optimization.

Reaction discovery and catalyst screening lie at the heart of synthetic organic chemistry. While there are efforts at de novo catalyst design using computation/artificial intelligence, at its core, synthetic chemistry is an experimental science. This review overviews biomacromolecule-assisted screening methods and the follow-on elaboration of chemistry so discovered. All three types of biomacromolecules discussed─enzymes, antibodies, and nucleic acids─have been used as "sensors" to provide a readout on product chirality exploiting their native chirality. Enzymatic sensing methods yield both UV-spectrophotometric and visible, colorimetric readouts. Antibody sensors provide direct fluorescent readout upon analyte binding in some cases or provide for cat-ELISA (Enzyme-Linked ImmunoSorbent Assay)-type readouts. DNA biomacromolecule-assisted screening allows for templation to facilitate reaction discovery, driving bimolecular reactions into a pseudo-unimolecular format. In addition, the ability to use DNA-encoded libraries permits the barcoding of reactants. All three types of biomacromolecule-based screens afford high sensitivity and selectivity. Among the chemical transformations discovered by enzymatic screening methods are the first Ni(0)-mediated asymmetric allylic amination and a new thiocyanopalladation/carbocyclization transformation in which both C-SCN and C-C bonds are fashioned sequentially. Cat-ELISA screening has identified new classes of sydnone-alkyne cycloadditions, and DNA-encoded screening has been exploited to uncover interesting oxidative Pd-mediated amido-alkyne/alkene coupling reactions.

SALTT study: A retrospective analysis of 111 SAlivary gland tumors of Lung and Tracheobronchial Tree.

INTRODUCTION: Primary pulmonary salivary gland-type tumours (PPSGT) are rare lung neoplasms arising from submucosal seromucinous glands in the central airway. METHODS AND RESULTS: We retrospectively analysed the clinicopathological features of 111 PPSGTs diagnosed at our institute between 2003 and 2021. The mean age at diagnosis was 43.8 years(range 6-78 years) and a male-to-female ratio of 2:1. On imaging, 92 % of cases had centrally located tumours and 37.3 % were early stage. The histopathological types included 70 cases (63 %) of mucoepidermoid carcinoma (MEC), 31 cases (27.7 %) of adenoid cystic carcinoma (ADCC), two cases of myoepithelial carcinoma, one case each of acinic cell carcinoma (ACC), clear cell carcinoma (CCC), epithelial myoepithelial carcinoma (EMC) and 5 others [including adenocarcinoma of minor salivary gland origin(n = 3), carcinoma with sebaceous differentiation(n = 1) and poorly differentiated carcinoma of salivary gland type(n = 1)]. The size of the tumours found in the resection specimens ranged from 1 cm to 13 cm, with an average size of 4.9 cm. High-risk attributes such as lymphovascular invasion (LVI), perineural invasion (PNI), pleural involvement, positive resection margins, and nodal metastasis were identified in 15.3 %, 15.3 %, 13.6 %,15.2 % and 6.7 % of cases, respectively. These attributes were found to be more frequent in ADCC than in MEC. Surgery was the main treatment modality [68/84 (80 %) cases]. ADCC cases had more recurrence and distant metastasis than MEC cases. The 3- year overall-survival (OS) and recurrence-free survival(RFS) were better in patients with age lesser than 60 years(p-value <0.0001), low pT stage (p-value 0.00038) and lower grade of MEC(p-value-0.0067). CONCLUSION: It is crucial to have an acquaintance with the morphologic spectrum and immunophenotypic characteristics of PPSGT to recognize them in this unusual location. In tandem, it is crucial to differentiate them from conventional primary non-small cell lung carcinoma, as the management protocols and prognostic implications differ significantly.

Mix-and-inject XFEL crystallography reveals gated conformational dynamics during enzyme catalysis.

How changes in enzyme structure and dynamics facilitate passage along the reaction coordinate is a fundamental unanswered question. Here, we use time-resolved mix-and-inject serial crystallography (MISC) at an X-ray free electron laser (XFEL), ambient-temperature X-ray crystallography, computer simulations, and enzyme kinetics to characterize how covalent catalysis modulates isocyanide hydratase (ICH) conformational dynamics throughout its catalytic cycle. We visualize this previously hypothetical reaction mechanism, directly observing formation of a thioimidate covalent intermediate in ICH microcrystals during catalysis. ICH exhibits a concerted helical displacement upon active-site cysteine modification that is gated by changes in hydrogen bond strength between the cysteine thiolate and the backbone amide of the highly strained Ile152 residue. These catalysis-activated motions permit water entry into the ICH active site for intermediate hydrolysis. Mutations at a Gly residue (Gly150) that modulate helical mobility reduce ICH catalytic turnover and alter its pre-steady-state kinetic behavior, establishing that helical mobility is important for ICH catalytic efficiency. These results demonstrate that MISC can capture otherwise elusive aspects of enzyme mechanism and dynamics in microcrystalline samples, resolving long-standing questions about the connection between nonequilibrium protein motions and enzyme catalysis.

Rapid Enantioselective and Diastereoconvergent Hybrid Organic/Biocatalytic Entry into the Oseltamivir Core.

A formal synthesis of the antiviral drug (-)-oseltamivir (Tamiflu) has been accomplished starting from m-anisic acid via a dissolving metal or electrochemical Birch reduction. The correct absolute stereochemistry is efficiently set through enzyme-catalyzed carbonyl reduction on the resultant racemic α,ß-unsaturated ketone. A screen of a broad ketoreductase (KRED) library identified several that deliver the desired allylic alcohol with nearly perfect facial selectivity at the new center for each antipodal substrate, indicating that the enzyme also is able to completely override inherent diastereomeric bias in the substrate. Conversion is complete, with d-glucose serving as the terminal hydride donor (glucose dehydrogenase). For each resulting diastereomeric secondary alcohol, O/N-interconversion is then efficiently effected either by synfacial [3,3]-sigmatropic allylic imidate rearrangement or by direct, stereoinverting N-Mitsunobu chemistry. Both stereochemical outcomes have been confirmed crystallographically. The α,ß-unsaturation is then introduced via an α-phenylselenylation/oxidation/pyrolysis sequence to yield the targeted (S)-N-acyl-protected 5-amino-1,3-cyclohexadiene carboxylates, key advanced intermediates for oseltamivir pioneered by Corey (N-Boc) and Trost (N-phthalamido), respectively.

Enhanced neuroinflammation and oxidative stress are associated with altered hippocampal neurogenesis in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine treated mice.

Loss of midbrain dopaminergic neurons in Parkinson's disease not only induces motor impairments but also leads to the development of non-motor symptoms such as memory impairment, anxiety and depression. Dopaminergic axons directly innervate hippocampus and release dopamine in the local environment of hippocampus, and hence are directly involved in the modulation of hippocampal-dependent functions. Studies have explored the potential effect of dopamine on adult hippocampal neurogenesis. However, it is not well defined whether oxidative damage and inflammation could be associated with alteration in adult hippocampal neurogenesis. In the present study, we analyzed the effect of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine on adult hippocampal neurogenesis and how it is associated with inflammatory conditions in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced mouse model of Parkinson's disease-like phenotypes. 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-treated mice exhibited significantly reduced dopaminergic neurons and dopamine content that resulted in impairment of motor functions. Interestingly, the formation of endogenous neuronal precursor cells and the number of neuroblasts in the hippocampus were significantly increased following 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine treatment. Net hippocampal neurogenesis was also reduced in the hippocampus after 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine treatment. These effects in the hippocampus were associated with increased oxidative stress markers and a massive reactive gliosis. Taken together, our results suggest that degeneration of midbrain dopaminergic neurons directly affects the local hippocampal microenvironment by enhancing inflammatory influences. The 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced inflammatory reaction in the hippocampus may alter the endogenous regenerative capacity of the brain. Therefore, anti-inflammatory agents could be a potential therapy for the improvement of the endogenous regenerative capacity of the aging or neurodegenerative brain.

Catalyst-controlled positional-selectivity in C-H functionalizations.

C-H bonds are ubiquitous in organic molecules and typically these bonds are chemically indistinct from each other and it would be highly advantageous for a synthetic chemist to have the ability to choose which C-H bond is functionalized in a given molecule. A controlled and positional-selective C-H bond functionalization is still a prominent goal in this area. With recent developments in transition metal-catalyzed regiodivergent C-H functionalizations, a switch in regioselectivity between two reactive sites within a given substrate is possible under catalytic control, and has profoundly impacted synthetic strategies. Switching site-selectivity within the same or similar precursors represents a great opportunity and challenge in altering the C-H functionalization from one reactive site to other by changing the choice of the catalytic system having a different mechanistic approach. This review discusses the potential and most common approaches employed in tweaking the catalytic systems to alter the positional-selectivity of C-H bond activation.

Redefining the role of peripheral LPS as a neuroinflammatory agent and evaluating the role of hydrogen sulphide through metformin intervention.

OBJECTIVE: The present study was aimed to enumerate the role of metformin-associated H2S release against lipopolysaccharide (LPS) induced neuroinflammation. MATERIALS AND METHODS: Five groups of animals were subjected to treatment as control (normal saline), toxic control (LPS, 125 µg/kg, i.p.), and three separate groups treated with 6.25, 12.5, and 25 mg/kg of metformin along with LPS for a period of 28 days. LPS was administered on 1st, 2nd, 3rd, 4th, 23rd, 24th, 25th and 26th day. The animals were evaluated for behavioral (elevated plus maze, rotarod and actophotometer); biochemical (plasma and tissue H2S, COX, LOX and NO), antioxidant (TBARS, SOD, catalase, protein carbonyl and GSH) and liver toxicity (SGOT and SGPT) markers. The brain tissues were further evaluated histopathologically, free fatty acid profile and NF-κB expression. RESULT: The LPS could not hasten any significant behavioral, biochemical, antioxidant and histopathological changes in the brain tissue. LPS also failed to modify the free fatty acid profile and NF-κB expression in the brain tissue. The LPS demarcated a well-defined peripheral inflammation as perceived through the plasma H2S, NO, SGOT and SGPT. Metformin administration demonstrated a marked effect on the peripheral inflammation induced by LPS. CONCLUSION: The LPS (i.p.) administration is devoid of any neuroinflammatory effects; however, precipitates peripheral inflammatory reactions and the same can could be attributed to the fact that LPS is devoid of/confined by very minimal permeability across the blood brain barrier. Metformin demonstrated a significant effect on peripheral inflammatory reactions precipitated through LPS.

Population dynamics and reproductive biology of Barilius bendelisis (Cyprinidae: Cypriniformes) from river Gaula of Central Indian Himalaya.

The Indian hill trout cyprinid, Barilius bendelisis is a member of family Cyprinidae that dwells in shallow, cold, and clear water. In this study, growth parameters and reproductive biology of Indian hill trout, Barilius bendelisis from river Gaula, Central Himalaya region, India, were studied. The length-frequency data were grouped sex wise and were analyzed to determine the growth and mortality parameters using the computer software programme, FAO-ICLARM Stock Assessment Tool (FISAT II). Altogether, 501 individuals were collected from river Gaula (November 2013-October 2014) and were preserved in formalin for further analysis. The results showed that the female outnumbered the male population. The minimum GSI of females was observed in the month of October (4.93 ± 0.26) and for males in the month of June and July (0.093 ± 0.12), whereas, the maximum value was in the month of April for both females (13.47 ± 0.52) and males (1.21 ± 0.12). Fluctuation in GSI values had a bimodal pattern showing two peaks during March-May and August-September in both the sexes, indicating the common spawning period of fish. The slope of regression showed the negative allometric growth for both males and females (b= 2.65 for male and b= 2.5 for female). A significant relationship between length and weight was observed in the present study (p < 0.05). The ELEFAN-I estimated L∞ and K of the von Bertalanffy growth factor for males (17.33 cm and 0.310 per year), females (17.33 cm and 0.3 per year) and pooled sexes (17.33 cm and 0.240 per year). The results indicated that Barilius bendelisis is a small sized fish having negative allometric growth that spawns twice a year. Thus, the present study on biological traits represents the baseline information for effective production, conservation and restoration planning.

Heteroatom-Guided, Palladium-Catalyzed, Site-Selective C-H Arylation of 4H-Chromenes: Diastereoselective Assembly of the Core Structure of Myristinin†B through Dual C-H Functionalization.

A highly site-selective, heteroatom-guided, palladium-catalyzed direct arylation of 4H-chromenes is reported. The C-H functionalization is driven not only by the substituents and structure of the substrate but also by the coupling partner being used. The diastereoselective assembly of the core structure of Myristinin B has been achieved by using a dual C-H functionalization strategy for regioselective direct arylation.

Exploration of human pancreatic alpha-amylase inhibitors from Physalis peruviana for the treatment of type 2 diabetes.

Type 2 Diabetes (T2D), a chronic metabolic disorder characterized by persistent hyperglycemia, accounts for ∼90% of all types of diabetes. Pancreatic α-amylase is a potential drug target for preventing postprandial hyperglycemia and inhibiting T2D in humans. Although many synthetic drugs have been identified against pancreatic α-amylase, however, reported several side effects, and plant-derived natural products are less explored against T2D. This study tested 34 flavonoids derived from the plant Physalis peruviana against the human pancreatic α-amylase (HPA) using in silico computational approaches such as molecular docking and molecular dynamics simulation approaches. Schrödinger, a drug discovery package with modules applicable for molecular docking, protein-ligand interaction analysis, molecular dynamics, post-dynamics simulation, and binding free energy calculation, was employed for all computational studies. Four flavonoids, namely, Chlorogenic acid, Withaperuvin F, Withaperuvin H, and Rutin, were picked based on their docking score ranging between -7.03 kcal/mol and -11.35 kcal/mol compared to the docking score -7.3 kcal/mol of reference ligand, i.e. Myricetin. The molecular dynamics analysis suggested that all flavonoids showed considerable stability within the protein's catalytic pocket, except chlorogenic acid, which showed high deviation during the last 15 ns. However, the interactions observed in initial docking and extracted from the simulation trajectory involved > 90% identical residues, indicating the affinity and stability of the docked flavonoids with the protein. Therefore, all four compounds identified in this study are proposed as promising antidiabetic candidates and should be further considered for their in vitro and in vivo validation.Communicated by Ramaswamy H. Sarma.

Robotic radical thymectomy-right-sided approach for a thymoma.

The utilization of a radical robotic thymectomy, with clearance of the mediastinal tissue between the two phrenic nerves for a thymoma, is well established. The complex mediastinal anatomy, limited space and the location of the heart introduce a distinctive challenge, particularly when adopting a right-sided approach to identify and dissect along the left phrenic nerve. We present our technique for performing a robotic radical thymectomy from a right-sided approach, tailored for a localized thymoma. Our goal is to showcase the efficacy and safety of this method, offering insights that can enhance surgical outcomes.

Treatment Response to Neoadjuvant Therapy in Squamous Esophageal Cancer-Correlation Between Metabolic Response and Histopathology.

PURPOSE: Esophageal cancer is among the leading causes of cancer-related mortality worldwide. Patients presenting with localized and loco-regionally advanced cancer without distant metastases have reasonable survival with multimodality management. Adequate and comprehensive staging is the backbone for proper selection of patients fit for curative treatment. Positron emission tomography (PET) in combination with contrast-enhanced computed tomography (CECT) is utilized as the standard staging modality. Multimodality treatment has been able to achieve evaluable tumor responses including pathological complete response (pCR). It is, therefore, necessary to understand whether the impact of neoadjuvant therapy can be evaluated on imaging, i.e., standardized uptake value (SUV) on PET scan done for response assessment and if this can be correlated with histopathological response and later, with survival. Squamous cell carcinoma (SCC) is more common globally and in the Indian subcontinent; hence, we chose this subgroup to evaluate our hypothesis. METHODS: This is a single institution, retrospective study. Out of the 1967 patients who were treated between 2009 and 2019, 1369 (78.54%) patients had SCC. Out of these, 44 received NACTRT, whereas 1325 received NACT followed by curative surgery. The standardized uptake value (SUV) of 18-fluorodeoxyglucose was recorded during pre- and post-neoadjuvant treatment (NAT) using positron emission tomography (PET). The histopathology of the final resection specimen was evaluated using the Mandard tumor regression grade (TRG) criteria with response being graded from 0 to 5 as no residual tumor (NRT), scanty residual tumor (SRT), and residual tumor We attempted to find a cut-off value of the post neoadjuvant SUV of the primary tumor site which correlated with achievement of better histopathological response. RESULTS: Out of 1325 patients of SCC esophagus who underwent surgery, 943 patients had available data of TRG, and it was categorized into the 0-2 category which had 325 patients (34.5%) and 3-5 category, 618 patients (65.5%). The SUV was taken only from the PET scans done at our institution, so as to achieve a more homogenous cohort, and this was available for 186 patients, 151 from the NACT group and 35 from the NACTRT group. The ROC method was used to find the cut-off for SUV (5.05) in the NACT cohort, which depicted significant difference in the outcome. Out of these, 93 patients who underwent NACT had SUV > 5.05 and 58 had SUV < 5.05. It was found that the subjective and objective histopathological scores correlated at a p value of < 0.0001. Specifically, the majority of cases with SRT tended to be in the 3-5 category of TRG, whereas cases with NRT are predominantly in the 0-2 category. In the ≥ 5.05 category of SUV, there were 76 cases with SRT. In the NACT cohort, the < 5.05 category of SUV, there are 26 cases with SRT and 32 cases with NRT. Among cases with SRT, 74.5% had SUV ≥ 5.05, while 25.5% had SUV < 5.05. Among cases with NRT, 34.7% had SUV ≥ 5.05, while 65.3% had SUV < 5.05 (p value 0.007). No significant association was found in the radio-pathological correlation in the NACTRT group. CONCLUSION: Our study confirms the correlation of post neoadjuvant chemotherapy PET SUV with histopathological response, the cut-off of SUV being 5.05 in our cohort. This confirms the predictive value of FDG PET as demonstrated in other studies. Furthermore, its prognostic value with respect to survival has been verified in multiple other studies. With larger scale randomized studies, we may be able to identify the group of patients who have borderline operability anatomically as well as physiologically, where alternative treatment regimens may be indicated to improve outcomes.

Clinical Utility of Stepwise Bronchoalveolar Lavage Fluid Analysis in Diagnosing and Managing Lung Infiltrates in Leukemia/Lymphoma Patients With Febrile Neutropenia.

PURPOSE: Febrile neutropenia (FN) is a serious complication in hematologic malignancies, and lung infiltrates (LIs) remain a significant concern. An accurate microbiological diagnosis is crucial but difficult to establish. To address this, we analyzed the utility of a standardized method for performing bronchoalveolar lavage (BAL) along with a two-step strategy for the analysis of BAL fluid. PATIENTS AND METHODS: This prospective observational study was conducted at a tertiary cancer center from November 2018 to June 2020. Patients age 15 years and older with confirmed leukemia or lymphomas undergoing chemotherapy, with presence of FN, and LIs observed on imaging were enrolled. RESULTS: Among the 122 enrolled patients, successful BAL was performed in 83.6% of cases. The study used a two-step analysis of BAL fluid, resulting in a diagnostic yield of 74.5%. Furthermore, antimicrobial therapy was modified in 63.9% of patients on the basis of BAL reports, and this population demonstrated a higher response rate (63% v 45%; P = .063). CONCLUSION: Our study demonstrates that a two-step BAL fluid analysis is safe and clinically beneficial to establish an accurate microbiological diagnosis. Given the crucial impact of diagnostic delays on mortality in hematologic malignancy patients with FN, early BAL studies should be performed to enable prompt and specific diagnosis, allowing for appropriate treatment modifications.

Phase III randomized trial comparing neoadjuvant paclitaxel+platinum to 5-fluorouracil+platinum in esophageal/GEJ squamous cell carcinoma.

PURPOSE: Standard neoadjuvant chemotherapy (NACT) for locally advanced esophageal/gastroesophageal junction squamous cancer (LAEGSC), 5-fluorouracil (5FU)+platinum, is toxic and logistically challenging; alternative regimens are needed. PATIENTS AND METHODS: Phase III randomized open-label non-inferiority trial at Tata Memorial Center, India, in resectable LAEGSC. Patients were randomized 1:1 to three cycles of 3-weekly platinum (cisplatin 75 mg/m2 or carboplatin AUC 6) with paclitaxel 175 mg/m2 (day 1) or 5FU 1000 mg/m2 continuous infusion (days 1-4), followed by surgery. RESULTS: Between August 2014 and June 2022, we enrolled 420 patients; 210 to each arm. Significantly more patients on paclitaxel + platinum (194 (92.3%)] received all 3 chemotherapy cycles than on 5FU+platinum (170 [85.9%]), P = .009. 5FU + platinum caused more grade ≥ 3 toxicities (124 [69.7%]) than paclitaxel + platinum (97 [51.9%]), P = .001. Surgery was performed in 131 (62.4%) patients on 5FU + platinum vs 139 (66.2%) on paclitaxel + platinum, P = .415. Paclitaxel + platinum resulted in higher pathologic primary tumor clearance (33 [25.8%]) vs 17 [15%]; P = .04), and pathologic complete responses in 21.9% compared to 12.4% from 5FU + platinum, P = .053. Median OS was 27.5 months (95% CI, 18.6-43.5) from paclitaxel + platinum, which was non-inferior to 27.1 months (95% CI, 18.8-40.7) from 5FU + platinum; HR, 0.89 (95% CI, 0.72-1.09); P = .346. CONCLUSION: Neoadjuvant paclitaxel + platinum chemotherapy is safer, and results in similar R0 resections, higher pathologic tumor clearance and non-inferior survival, compared to 5FU + platinum. Paclitaxel + platinum should replace 5FU + platinum as NACT for resectable LAEGSC. CLINICAL TRIALS REGISTRY INDIA NUMBER: CTRI/2014/04/004516.

Changes in an enzyme ensemble during catalysis observed by high-resolution XFEL crystallography.

Enzymes populate ensembles of structures necessary for catalysis that are difficult to experimentally characterize. We use time-resolved mix-and-inject serial crystallography at an x-ray free electron laser to observe catalysis in a designed mutant isocyanide hydratase (ICH) enzyme that enhances sampling of important minor conformations. The active site exists in a mixture of conformations, and formation of the thioimidate intermediate selects for catalytically competent substates. The influence of cysteine ionization on the ICH ensemble is validated by determining structures of the enzyme at multiple pH values. Large molecular dynamics simulations in crystallo and time-resolved electron density maps show that Asp17 ionizes during catalysis and causes conformational changes that propagate across the dimer, permitting water to enter the active site for intermediate hydrolysis. ICH exhibits a tight coupling between ionization of active site residues and catalysis-activated protein motions, exemplifying a mechanism of electrostatic control of enzyme dynamics.

Lipidomics and proteomics: An integrative approach for early diagnosis of dementia and Alzheimer's disease.

Alzheimer's disease (AD) is the most common neurodegenerative disorder and considered to be responsible for majority of worldwide prevalent dementia cases. The number of patients suffering from dementia are estimated to increase up to 115.4 million cases worldwide in 2050. Hence, AD is contemplated to be one of the major healthcare challenge in current era. This disorder is characterized by impairment in various signaling molecules at cellular and nuclear level including aggregation of Aß protein, tau hyper phosphorylation altered lipid metabolism, metabolites dysregulation, protein intensity alteration etc. Being heterogeneous and multifactorial in nature, the disease do not has any cure or any confirmed diagnosis before the onset of clinical manifestations. Hence, there is a requisite for early diagnosis of AD in order to downturn the progression/risk of the disorder and utilization of newer technologies developed in this field are aimed to provide an extraordinary assistance towards the same. The lipidomics and proteomics constitute large scale study of cellular lipids and proteomes in biological matrices at normal stage or any stage of a disease. The study involves high throughput quantification and detection techniques such as mass spectrometry, liquid chromatography, nuclear mass resonance spectroscopy, fluorescence spectroscopy etc. The early detection of altered levels of lipids and proteins in blood or any other biological matrices could aid in preventing the progression of AD and dementia. Therefore, the present review is designed to focus on the recent techniques and early diagnostic criteria for AD, revealing the role of lipids and proteins in this disease and their assessment through different techniques.

Crosstalk between Adult Hippocampal Neurogenesis and Its Role in Alzheimer's Disease.

The functional and developmental unit of neurogenesis is neural stem cells (NSCs). These NSCs have self-renewal capacity and produce new neurons throughout life in different neurogenic niche. Neurogenesis in adult brain is associated with synaptic plasticity, learning, and memory in dentate gyrus (DG) of hippocampus and olfactory bulb. Remarkably, weakened neurogenesis has been viewed before the onset of different pathological hallmarks of neurological disorders. In this review, we have provided evidence which implicates impaired neurogenesis as a culprit in age associated neurological disorders with greater emphasis on Alzheimer's disease (AD). Moreover, an insight about the molecular and cellular regulation linked with altered neurogenesis in young and aging brain has also been discussed. This review further summarizes the therapeutic strategies for targeting the manipulation of the neural stem cell pool and factors affecting the pool involved in AD.

Caffeine improves memory and cognition via modulating neural progenitor cell survival and decreasing oxidative stress in Alzheimer's rat model.

AIMS: Caffeine possesses potent antioxidant, anti-inflammatory and anti-apoptotic activities against a variety of neurodegenerative diseases, including Alzheimer's disease (AD) and Parkinson's disease (PD). The goal of this study was to investigate the protective role of a psychoactive substance like caffeine on hippocampal neurogenesis and memory functions in streptozotocin (STZ)-induced neurodegeneration in rats. BACKGROUND: Caffeine is a natural CNS stimulant, belonging to the methylxanthine class, and is a widely consumed psychoactive substance. It is reported to abate the risk of various abnormalities that are cardiovascular system (CVS) related, cancer related, or due to metabolism dysregulation. Short-term caffeine exposure has been widely evaluated, but its chronic exposure is less explored and pursued. Several studies suggest a devastating role of caffeine in neurodegenerative disorders. However, the protective role of caffeine on neurodegeneration is still unclear. OBJECTIVE: Here, we examined the effects of chronic caffeine administration on hippocampal neurogenesis in intracerebroventricular STZ injection induced memory dysfunction in rats. The chronic effect of caffeine on proliferation and neuronal fate determination of hippocampal neurons was evaluated by co-labeling of neurons by thymidine analogue BrdU that labels new born cells, DCX (a marker for immature neurons) and NeuN that labels mature neurons. METHOD: STZ (1 mg/kg, 2 µl) was injected stereotaxically into the lateral ventricles (intracerebroventricular injection) once on day 1, followed by chronic treatment with caffeine (10 mg/kg, i.p) and donepezil (5 mg/kg, i.p.). Protective effect of caffeine on cognitive impairment and adult hippocampal neurogenesis was evaluated. RESULT: Our findings show decreased oxidative stress burden and amyloid burden following caffeine administration in STZ lesioned SD rats. Further, double immunolabeling with bromodeoxyuridine+/doublecortin+ (BrdU+/DCX+) and bromodeoxyuridine+/ neuronal nuclei+ (BrdU+/NeuN+) has indicated that caffeine improved neuronal stem cell proliferation and long term survival in STZ lesioned rats. CONCLUSION: Our findings support the neurogenic potential of caffeine in STZ induced neurodegeneration.

Activation of Angiotensin-converting Enzyme 2 Protects Against Lipopolysaccharide-induced Glial Activation by Modulating Angiotensin-converting Enzyme 2/Angiotensin (1-7)/Mas Receptor Axis.

Neuroinflammation is associated with activation of glial cells and pro-inflammatory arm of the central Renin Angiotensin System (RAS) namely, Angiotensin-Converting Enzyme/Angiotensin II/Angiotensin Type 1 Receptor (ACE/Ang II/AT1R) axis. Apart from this, another axis of RAS also exists, Angiotensin-Converting Enzyme 2/Angiotensin (1-7)/Mas Receptor (ACE2/Ang (1-7)/MasR), which counters ACE/Ang II/AT1R axis by showing anti-inflammatory properties. However, the role of ACE2/Ang (1-7)/MasR axis has not been explored in glial activation and neuroinflammation. Hence, the present study tries to unveil the role of ACE2/Ang (1-7)/MasR axis in lipopolysaccharide (LPS)-induced neuroinflammation using diminazene aceturate (DIZE), an ACE2 activator, in astroglial (C6) and microglial (BV2) cells as well as male SD rats. We found that ACE2 activation efficiently prevented LPS-induced changes by decreasing glial activation, inflammatory signaling, cell migration, ROS generation via upregulation of ACE2/Ang (1-7)/MasR signaling. In addition, activation of ACE2/Ang (1-7)/MasR axis by DIZE significantly suppressed the pro-inflammatory ACE/Ang II/AT1R axis by reducing Ang II level in neuroinflammatory conditions induced by LPS in both in vitro and in vivo. ACE2/Ang (1-7)/MasR axis activation further decreased mitochondrial depolarization and apoptosis, hence providing neuroprotection. Furthermore, to validate that the beneficial effect of the ACE2 activator was indeed through MasR, a selective MasR antagonist (A779) was used that significantly blocked the anti-inflammatory effect of ACE2 activation by DIZE. Hence, our study demonstrated that ACE2 activation imparted neuroprotection by enhancing ACE2/Ang (1-7)/MasR signaling which in turn decreased glial activation, neuroinflammation, and apoptosis and improved mitochondrial health.