👤 Mohinder Pal Sachdeva

Endosomal system dysfunction within neurons is a prominent early feature of Alzheimer's disease (AD) pathology. Multiple AD risk factors are regulators of endocytosis and known to cause hyperactivity of the early endosome small GTPase rab5, resulting in neuronal endosomal pathway disruption and cholinergic neurodegeneration. Adaptor protein containing Pleckstrin homology domain, Phosphotyrosine binding domain, Leucine zipper motif (APPL1), an important rab5 effector protein and signaling molecule has been shown in vitro to interface between endosomal and neuronal dysfunction through a rab5-activating interaction with the BACE1-generated C-terminal fragment of amyloid precursor protein (APP-βCTF), a pathogenic APP fragment generated within endosomal compartments. To understand the contribution of APPL1 to AD-related endosomal dysfunction in vivo, we generated a transgenic mouse model overexpressing human APPL1 within neurons (Thy1-APPL1). Strongly supporting the important endosomal regulatory roles of APPL1 and their relevance to AD etiology, Thy1-APPL1 mice (both sexes) develop enlarged neuronal early endosomes and increased synaptic endocytosis due to increased rab5 activation. We demonstrated pathophysiological consequences of APPL1 overexpression, including functional changes in hippocampal long-term potentiation (LTP) and long-term depression (LTD), degeneration of large projection cholinergic neurons of the basal forebrain, and impaired hippocampal-dependent memory. Our evidence shows that neuronal APPL1 elevation modeling its functional increase in the AD brain induces a cascade of AD-related pathological effects within neurons, including early endosome anomalies, synaptic dysfunction, and selective neurodegeneration. Our in vivo model highlights the contributions of APPL1 to the pathobiology and neuronal consequences of early endosomal pathway disruption and its potential value as a therapeutic target. Show less

Endosomal system dysfunction within neurons is a prominent early feature of Alzheimer's disease (AD) pathology. Multiple AD risk factors are regulators of endocytosis and are known to cause hyper-activity of the early-endosome small GTPase rab5, resulting in neuronal endosomal pathway disruption and cholinergic neurodegeneration. Adaptor protein containing Pleckstrin homology domain, Phosphotyrosine binding domain, Leucine zipper motif (APPL1), an important rab5 effector protein and signaling molecule, has been shown Neuronal endosome dysfunction appears early in Alzheimer's disease (AD) and is linked to memory loss. Genes and risk factors associated with AD often increase rab5 activity, a protein that disrupts endosomal signalling when hyperactivated. APPL1, a key rab5 partner, worsens this dysfunction via its interaction with APP-βCTF, a protein fragment associated with AD. To explore APPL1's role, we created a genetically modified mouse that overexpresses APPL1 in neurons. This model provides the first Show less

Achondroplasia, the most prevalent skeletal dysplasia, is a genetic disorder caused by activating mutations in the FGFR3 gene impairing endochondral ossification of long bones. Clinical manifestations include disproportionate short stature and multisystem complications. Management has been limited to supportive care, surgical limb lengthening, and recombinant human growth hormone. The latter two carry significant risks and provide modest benefits, respectively. Recently, targeted molecular therapies have emerged as promising alternatives. This review highlights three investigational agents: Vosoritide, Infigratinib, and Navepegritide. Vosoritide, an injectable C-type natriuretic peptide analog, reduces MAPK pathway overactivation; Infigratinib, an oral FGFR1-3 inhibitor, directly suppresses downstream signaling; and Navepegritide, a long-acting CNP prodrug, sustains MAPK inhibition. Clinical trials in children aged 5 years and older demonstrate improved annualized growth velocity compared to baseline: 1.7 cm/year with Vosoritide, 6.0 cm/year with Infigratinib, and 5.4 cm/year with Navepegritide. Safety profiles are favorable with few to no significant treatment-related adverse events reported in the trials reviewed; radius fracture, adenoidal hypertrophy, and sleep apnea were reported for Vosoritide, injection site reactions were reported for Navepegritide, and nasopharyngitis was reported for Infigratinib. Direct comparisons across trials are limited, but available data suggest all three therapies bring growth trajectories of children with achondroplasia closer to unaffected peers. Long-term outcomes, particularly regarding comorbidities such as foramen magnum stenosis, spinal stenosis, and sleep apnea, remain under investigation. These emerging treatments represent a paradigm shift in achondroplasia management, underscoring the need for head-to-head studies and evaluation of combination strategies to optimize efficacy and durability. Show less

Perfluorooctanesulfonic acid (PFOS) is a persistent environmental pollutant widely present in ecosystems and humans, linked to numerous diseases, including cancers, due to its potent toxicity. Despite its harmful effects, effective strategies for mitigating PFOS-induced toxicity remain undeveloped or at best underdeveloped. In this effort, we explore the concept of toxicity reversal by loci-specific DNA methylation editing to reverse PFOS-induced toxicity, whereby key cellular processes such as proliferation, migration, and apoptosis are restored. To demonstrate our concept, we employed CRISPR-dCas9 epigenome editing tools, utilizing catalytically deactivated Cas9 fused with either DNA methyltransferases or ten-eleven translocation ( Show less

Neurexins (NRXNs), a complex family of synapse regulatory proteins, represent attractive candidate molecular mediators of retinal neuronal dysfunction in early diabetic retinal disease (DRD) given their roles in the central nervous system and recent work suggesting a potential link with diabetes mellitus (DM). As antibodies are unable to distinguish NRXN family members and isoforms, the purpose of this study was to investigate differential expression of individual NRXN transcripts in relevant retinal cell types in early DRD. RNAscope multiplexed fluorescent in situ hybridization was used to quantify transcripts of NRXNs in mouse and human retina. DM was induced in C57BL/6J mice using streptozotocin (STZ) and the retinal phenotype characterized by electroretinogram (ERG), optical coherence tomography (OCT), and optokinetic tracking (OKT) after 6 weeks. Retinal ganglion cells (RGCs) were generated in vitro by directed differentiation from human embryonic stem cells (hESCs), cultured in normal or high glucose, and NRXN expression assessed by qPCR and Western blot. All NRXN family members (NRXN1, NRXN2, and NRXN3) were enriched in inner retinal neurons in both human and mouse tissue. We identified decreased Nrxn3 transcripts, specifically the Nrxn3β isoform, in RGCs of diabetic mice at 6 weeks after STZ treatment. Interestingly, Nrxn3α and Nrxn3β were differentially expressed in inner retinal layers. Finally, we confirmed decreased Nrxn3β expression in hESC-RGCs cultured in high glucose in vitro. Our findings suggest that NRXNs may play cell-type-specific roles in the inner retina and associate decreased Nrxn3β expression in RGCs with inner retinal dysfunction in early DRD. Show less

Philadelphia chromosome (Ph)-like B-acute lymphoblastic leukemia (B-ALL) is a clinically significant, high-risk genetic subtype of B-ALL cases. There are few data on the incidence, characterization, and treatment outcomes of Ph-like ALL cases from low- and middle-income countries. There is a pressing need to establish a well-organized/cost-effective approach for identifying Ph-like ALL instances. Multiplex reverse transcriptase polymerase chain reaction, nCounter NanoString, and fluorescence in situ hybridization were used to detect and characterize Ph-like ALL cases among recurrent genetic abnormalities (RGA) Of 130 newly diagnosed B-ALL cases, 25% (BCR::ABL1), 4% (ETV6::RUNX1), 5% (TCF3::PBX1), 2% (KM2TA::AFF1), and 65% RGA This study showed the high incidence of Ph-like ALL cases with kinase activating alterations and treatment outcomes from low- and middle-income region. Furthermore, a surrogate cost-effective multiplex panel of 11 overexpressed genes for the prompt detection of Ph-like ALL cases is proposed. Identification of recurrent gene abnormalities (RGA) Show less

Gene expression profiling is the criterion standard for recognizing Ph-like ALL signatures among B-ALLs. The prerequisite of GEP is the accurate normalization of target genes with stable expression of housekeeping genes in a quantitative PCR. HKGs exhibit differential expression in the different experimental conditions and affect the target genes' expression, leading to imprecise qPCR results. The selection of stable HKGs is crucial in GEP experiments, especially in identifying high-risk Ph-like ALL cases. We have evaluated the expression stability of nine HKGs (GAPDH, ACTB, GUSB, RNA18S, EEF2, PGK1, B2M, TBP and ABL1) in identified Ph-like ALLs and Ph-negative (n = 23 each) using six algorithms, 4 traditional softwares; geNorm, BestKeeper, NormFinder, Delta Cq value method, and two algorithms, RefFinderTM and ComprFinder. Further, we have validated the expression of 8 overexpressed normalized genes in Ph-like ALL cases (JCHAIN, CA6, MUC4, SPATS2L, BMPR1B, CRLF2, ADGRF1 and NRXN3). GeNorm, BestKeeper, NormFinder, Delta Cq value method, RefFinderTM and ComprFinder algorithm analysis revealed that EEF2, GAPDH, and PGK1 form the best representative HKGs in Ph-like ALL cases, while RNA18s, ß-actin, and ABL1 in Ph-negative ALLs. Lastly, we performed a correlation analysis and found that the combination of EEF2, GAPDH, and PGK1 represents the best combination with a very high correlation in Ph-like ALL cases. This is the first report that shows EEF2, GAPDH, and PGK1 are the best HKG genes and can be used in the diagnostic panel of Ph-like ALL cases using qPCR at baseline diagnosis. Show less

Benign prostatic hyperplasia (BPH) is a commonly occurring disease in aging men. It involves cellular proliferation of stromal and glandular tissues leading to prostate enlargement. Current drug therapies show several adverse effects such as sexual dysfunctions and cardiovascular side effects. Therefore, there is a need to develop more effective medical treatment for BPH. In this regard, we aimed to identify genes which play a critical role in BPH. We have obtained the dataset of differentially expressed genes (DEGs) of BPH from NCBI GEO. DEGs were investigated in the context of their protein-protein interactions (PPI). Hub genes i.e. genes associated with BPH were scrutinized based on the topological parameters of the PPI network. These were analyzed for functional annotations, pathway enrichment analysis and transcriptional regulation. In total, 38 hub genes were identified. Hub genes such as transcription factor activator protein-1 and adiponectin were found to play key roles in cellular proliferation and inflammation. Another gene peroxisome proliferator activated receptor gamma was suggested to cause obesity, a common comorbidity of BPH. Moreover, our results indicated an important role of transforming growth factor-beta (TGF-β) signaling and smooth muscle cell proliferation which may be responsible for prostate overgrowth and associated lower urinary tract symptoms frequently encountered in BPH patients. Zinc finger protein Snai1 was the most prominent transcription factor regulating the expression of hub genes that participate in TGF-β signaling. Overall, our study has revealed significant hub genes that can be employed as drug targets to develop potential therapeutic interventions to treat BPH. Show less

Nonalcoholic fatty liver disease (NAFLD) is characterized by the accumulation of fat in the liver without any history of chronic alcohol consumption. It encompasses a wide spectrum of diseases that range from simple steatosis to nonalcoholicsteatohepatitis. NAFLD is strongly associated with obesity, insulin resistance / type-2 diabetes mellitus and the metabolic syndrome. NAFLD is a complex disorder; environmental and genetic factors interact with NAFLD manifestation and determine its progression. In this review, an attempt was made to provide current information on the genetic variants of NAFLD in Asian populations. Literature search was performed by using PubMed, Medline and Google Scholar database. Candidate gene, validation and genomewide association studies (GWASs) were included in this review. A total of 41 studies fulfilled inclusion criteria of which 12 candidate gene studies exclusively focussed on the Show less

Obesity is one of the largest global health problems associated with increased morbidity and mortality mediated by its association with several other metabolic disorders. The interaction between the genes and environment plays an important role in the manifestation of obesity. Despite a high heritability (40-70%) of obesity, the search for genetic variants associated with obesity susceptibility has been a challenging task. To date, limited studies have been conducted in India, restricted to the validation of few genetic variants identified by genomewide association studies. In this critical review, we sought to examine the current knowledge of genetic basis of obesity and its measures in the Indian population. A comprehensive literature search was performed using 'PubMed', 'Medline' and 'IndMed' databases to search for citations published until 31st May 2017, using the key terms as 'Genetics' AND 'obesity' AND 'India'. We identified 48 potential studies which fulfilled the eligibility criteria. The findings indicated that Show less