Biology subjects

Hussain, M.

Publications and source records attributed to Hussain, M..

17 recordsLinked to original sources

bioRxiv2026

Long-PDE4D degradation attenuates left ventricular cardiomyocyte hypertrophic remodelling

Spatial compartmentalisation enables cyclic AMP (cAMP) to regulate distinct cellular functions, yet selectively targeting disease-associated signalling remains challenging. Phosphodiesterases constrain local cAMP responses, but conventional inhibitors offer limited isoform selectivity. Here we investigate whether targeted degradation of long phosphodiesterase-4D (PDE4D) isoforms can suppress pathological growth while preserving contractile function. Using adult rat and human ventricular cardiomyocytes and human myocardial slices, we show that the proteolysis-targeting chimera KTX-184 enhances compartmentalised cAMP signalling and attenuates hypertrophic remodelling. In rat cardiomyocytes, KTX-184 increases {beta}-adrenergic cAMP responses in the cytosol and at the plasma membrane, including T-tubule and crest regions, and enhances nuclear protein kinase A activity. In contrast, phospholamban- and ryanodine receptor-associated cAMP nanodomains, calcium transients and sarcomere shortening remain unchanged. KTX-184 prevents angiotensin II-induced hypertrophic remodelling, preserves T-tubule organisation and normalises hypertrophic marker expression. In human cardiomyocytes, it increases cytosolic cAMP responses and prevents overload-induced hypertrophy in myocardial slices. These findings identify long PDE4D isoforms as targets for spatially selective modulation of cAMP signalling and support targeted degradation as an approach to suppress cardiac hypertrophy without increasing contractility.

pharmacology and toxicology↗

bioRxiv2026

AI-enabled Spatial Profiling of Circulating Tumor-Immune Ecosystems Predicts Patient Outcomes Across Cancers

Circulating tumor cells (CTCs) and immune cells form dynamic multicellular ecosystems in blood, but their spatial organization and clinical relevance have not been systematically characterized. We developed the Cell and Cluster Identification Program (CCIP), an artificial intelligence-based framework that analyzes routine multiplex immunofluorescence blood scans to segment cells, identify CTCs and five immune lineages with high accuracy, and quantify multicellular clusters and tumor-immune interactions. Applying CCIP to 2,693 blood scans from 1,399 patients, we profiled over 60 million cells (>7 million multi-cell clusters) and linked imaging-derived features to patient outcomes. Correlated with circulating-tumor DNA mutation burdens, a 14-feature image model predicted overall survival in breast cancer, outperformed clinicopathologic variables and CTC enumeration, and generalized to prostate cancer. Prognostic imaging signatures were also associated with therapy response-related progression-free survival as well as with single-cell RNA sequencing-derived immune suppression states, connecting circulating tumor-immune architecture with systemic immune dysfunction.

cancer biology↗

bioRxiv2026

Genomic Determinants of Lethality and Therapeutic Vulnerability in Castration-Resistant Prostate Cancer

Despite extensive characterization, the molecular determinants that shape disease progression and therapeutic outcomes in metastatic castration-resistant prostate cancer (mCRPC) remain incompletely defined. This large, multi-institutional analysis reveals that the genomic determinants of outcomes in primary prostate cancer are distinct from those in castration-resistant disease. We identify androgen-regulated MYC fusions as potent primary genetic drivers catalyzing early progression. Additionally, across independent mCRPC cohorts, we validate TP53, RB1, and CDKN1B alterations as the strongest genetic drivers of poor survival. Mechanistically, CDKN1B loss induces an AR-positive epithelial-mesenchymal transition rather than neuroendocrine differentiation, while TP53 loss triggers whole-genome duplication and subsequent adaptive copy-number gains. Within TP53-altered tumors, AR amplifications confer improved survival while AR mutations are protective regardless of TP53 status. Integrating these genomic events with transcriptomic phenotypes, we derive CAPrisk, a multi-omic prognostic classifier. CAPrisk stratifies patients with mCRPC into three risk groups with >33-month survival differences and predicts outcomes across androgen receptor pathway inhibitors, taxanes, PARP-inhibitors, and radium-223. Together, these findings expand the clinical utility of genomic profiling in advanced prostate cancer and establish a framework for risk stratification in lethal disease. IN BRIEF (eTOC BLURB)Rebernick et al. analyze a multi-institutional cohort of 1,331 prostate cancer samples and identify the genomic determinants of progression to lethal, castration-resistant disease. They define rare AR-regulated MYC fusions and haploinsufficient CDKN1B loss as drivers of poor outcome while highlighting AR alterations as predictors of improved prognosis. They develop CAPrisk, a multi-omic classifier that stratifies patient outcomes across androgen receptor pathway inhibitors, taxanes, PARP-inhibitors, and radium-223. HIGHLIGHTS- AR-regulated MYC fusions are rare ([~]2%) truncal events driving aggressive disease. - Distinct AR alterations drive favorable outcomes in TP53-altered and non-altered contexts. - Haploinsufficient CDKN1B loss predicts poor survival in AR-positive tumors. - A multi-omic model predicts outcomes across four standard-of-care therapies. MI-OncoSeq TeamChandan Kumar, Erica Rabban, Kayla Muschong, Lakshmi P. Kunju, Javed Siddiqui, Yu Ning, Rui Wang, Fengyun Su, Yelena Kleyman-Smith, Josh N. Vo, Jin Chen, Rahul Mannan Stand Up To Cancer TeamWassim Abida, Joanna Cyrta, Glenn Heller, Davide Prandi, Joshua Armenia, Ilsa Coleman, Matteo Benelli, Eliezer M. Van Allen, Andrea Sboner, Tarcisio Fedrizzi, Juan Miguel Mosquera, Brian D. Robinson, Navonil De Sarkar, Lakshmi P. Kunju, Scott Tomlins, Daniel Nava Rodrigues, Massimo Loda, Anuradha Gopalan, Victor E. Reuter, Colin C. Pritchard, Joaquin Mateo, Diletta Bianchini, Susana Miranda, Suzanne Carreira, Pasquale Rescigno, Julie Filipenko, Jacob Vinson, Robert B. Montgomery, Himisha Beltran, Elisabeth I. Heath, Howard I. Scher, Philip W. Kantoff, Mary-Ellen Taplin, Nikolaus Schultz, Johann S. deBono, Francesca Demichelis, Peter S. Nelson, Mark A. Rubin, Charles Sawyers

Cancer Biology↗

bioRxiv2025

Mechanism of single-strand annealing from native mass spectrometry and cryo-EM structures of RAD52 homolog Mgm101

RAD52, the primary single-strand annealing (SSA) protein in humans, forms undecameric rings that bind ssDNA within a narrow, positively-charged groove. Whether RAD52 anneals two complementary ssDNAs on the same ring in cis, or between two ring-ssDNA complexes in trans, is unknown. Here, we determined cryo-EM structures of Mgm101, a RAD52 homolog from yeast mitochondria, in complexes with ssDNA, a duplex intermediate of annealing, and B-form dsDNA product. In all states, Mgm101 forms a closed nonadecameric ring that binds the backbone of the first ssDNA at the base of the narrow groove. The second complementary strand binds directly on top of the first to form an extended, unwound, and circular duplex intermediate of annealing. The third complex captures apparent B-form DNA product bound to a novel {beta}-hairpin motif located on top of the Mgm101 ring, above the primary DNA-binding groove. Mass photometry and native mass spectrometry confirm and further elucidate the complexes formed in solution. Altogether, our data reveal the full SSA pathway of Mgm101 and suggest it anneals two complementary ssDNAs on the same ring in cis. Structural conservation with RAD52 suggests it is likely to use a similar cis mechanism of annealing.

biochemistry↗

bioRxiv2025

Isolation of Cyclotide Gene from Solanaceae Family and Its Bioinformatics Analysis

Cyclotides are highly tolerant of sequence variability, aside from the conserved residues forming the cystine knot. Cyclotides have attractive natural movement capabilities including cytotoxicity, harmfulness to HIV, antimicrobials, insecticides, uterine contraction and inhibition of proteases, making them very important in pharmacy and horticulture. The medicinal cyclotides may be able to reimburse the safety of antimicrobials, which is a noticeable problem worldwide today. The present study was focused on the isolation of genes that encoding cyclotide, from plant species. DNA was isolated by CTAB method. The gene was amplified by PCR and after agarose gel electrophoresis confirmation that gene was sequenced followed by bioinformatics analysis. Petunia showed 90% to 97% identity with cds of reference sequence and 27 amino acids were identical in multiple alignment of protein sequence. In addition to providing information for the future investigation of Solanaceae species for cyclotides, this work will aid in understanding the plant families that produce cyclotides.

genetics↗

bioRxiv2025

Unveiling the pathogenicity of Cunninghamella echinulata SMH-1 and its bioactive metabolites through metabolomics: Dual-action disruption of Solenopsis invicta mitochondrial bioenergetics and cuticular integrity

The invasive red imported fire ant, Solenopsis invicta, poses significant ecological and economic challenges, necessitating sustainable alternatives to conventional pest control. This study evaluates the biocontrol potential of Cunninghamella echinulata isolate SMH-1, an entomopathogenic fungus, through integrated morphological, biochemical, and metabolomic analyses. Light and scanning electron microscopy elucidated infection dynamics, revealing conidial germination, cuticular penetration, and systemic hyphal proliferation, culminating in complete cadaver colonization. At 1x10 conidia/mL, SMH-1 achieved 100% mortality in S. invicta workers within 7 days, with virulence maintained across thermal gradients (10-30{degrees}C). Acetone extracts of SMH- 1 induced dose-dependent lethality, reaching 100% mortality at 1,000 mg/L. Nineteen significantly differentiated metabolites were identified from phospholipids category through UPLC/MS analysis of isolate SMH-1. The derived compounds also showed strong potential against S. invicta, among which dihydrocoumarin caused 100% mortality over 12-days of exposure. The bioactivity of isolate SMH-1 (Conidia), (extracts) and (dihydrocoumarin) against S. invicta revealed significantly differentiated metabolites as (Sulfolithocholylglycine, PE(18_1(9Z)_0_0), CE(12:0), LysoPI(18:1(9Z)/0:0) and Hydroxydestruxin B), (Tropine, lignoceric acid, 9-deoxy-9-methylene-16,16-dimethyl-PGE2, Flecainide and Jubanine B), and (3-O-alpha-D-Glucopyranuronosyl-D-xylose, Rilmakalim, 2-Amino-3-methyl-1-butanol, 2,4-Dimethyl-1,3-oxazole-5-carboxylic acid and Caffeinol), respectively. Citrate cycle (TCA) was significantly impacted by differential expression of pyruvate, pyruvic acid, succinic acid and fumaric acid. These findings underscore SMH-1s multifaceted biocontrol potential, combining direct pathogenicity, thermo-tolerance, and metabolite-mediated toxicity. By delineating host-pathogen interactions and metabolic disruptions, this work advances C. echinulata isolate SMH-1 as a sustainable candidate for integrated S. invicta management, offering an eco-friendly alternative to synthetic insecticides. Author SummaryInvasive fire ants (S. invicta) threaten ecosystems and agriculture worldwide, and current chemical controls often harm the environment. In this study, we explored a natural alternative: a soil-dwelling fungus called Cunninghamella echinulata (strain SMH-1). We discovered that this fungus can kill fire ants with remarkable efficiency. When applied directly, its spores caused 100% ant mortality within a week, even under varying temperatures. We also identified key fungal compounds, including dihydrocoumarin, which are lethal to ants. By studying how the fungus invades and disrupts the ants biology-such as breaking down their protective outer layers and interfering with their energy production, we revealed why SMH-1 is so effective. Our findings highlight SMH-1s potential as a safe, eco-friendly biocontrol agent. This fungus could reduce reliance on synthetic pesticides, offering farmers and communities a sustainable tool to combat fire ant invasions while protecting biodiversity. Our work bridges lab discoveries and real-world pest management, paving the way for greener solutions in agriculture and ecosystem conservation.

microbiology↗

bioRxiv2023

Exploring the Therapeutic Potential of Cannabis Constituents in Parkinson's Disease: Insights from Molecular Docking Studies

Cannabis, often known as marihuana, marijuana, hashish, and hash, belongs to the genus Cannabis sativa L. This plant has excellent potential for the treatment of several brain disorders. Phytochemical compounds in this plant act as antioxidants, preserving synaptic plasticity and preventing neuronal degeneration. The neurodegenerative condition Parkinsons has emerged as one of the most significant health concerns of the twenty-first century. A detailed in silico molecular docking study was carried out to assess the neuroprotective effects of cannabis compounds against four potential targets of PD, including monoamine oxidase B (MAO-B), catechol-O-methyltransferase (COMT), alpha-synuclein (ASN), and Adenosine A2A receptor (A2A). Physicochemical properties, drug-likeness, toxicity, and ADMET profiles were also investigated. In this docking study, the cannabis compound cannabicyclol showed a superior docking score of -10.8 kcal/mol with the MAO-B protein. Based on these results, cannabicyclol and the target protein MAO-B were used to perform MD simulations to analyze their stability at 100 ns. Furthermore, it is crucial to carry out in vitro and in vivo investigations to enhance the potency of cannabis components and understand the processes underlying the suppression of Parkinsons disease-related enzymes. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=145 SRC="FIGDIR/small/566677v1_ufig1.gif" ALT="Figure 1"> View larger version (43K): org.highwire.dtl.DTLVardef@15f455borg.highwire.dtl.DTLVardef@1c26038org.highwire.dtl.DTLVardef@3b32c6org.highwire.dtl.DTLVardef@82926b_HPS_FORMAT_FIGEXP M_FIG C_FIG

bioinformatics↗

bioRxiv2023

In Silico Analysis of Drug Off-Target Effects on Diverse Isoforms of Cervical Cancer for Enhanced Therapeutic Strategies

Cervical cancer is a severe medical issue as 500,000 new cases of cervical cancer are identified in the world every year. The selection and analysis of the suitable gene target are the most crucial in the early phases of drug design. The emphasis at one protein while ignoring its several isoforms or splice variations may have unexpected therapeutic or harmful side effects. In this work, we provide a computational analysis of interactions between cervical cancer drugs and their targets that are influenced by alternative splicing. By using open-accessible databases, we targeted 45 FDA-approved cervical cancer drugs targeting various genes having more than two distinct protein-coding isoforms. Binding pocket interactions revealed that many drugs do not have possible targets at the isoform level. In terms of size, shape, electrostatic characteristics, and structural analysis have shown that various isoforms of the same gene with distinct ligand-binding pocket configurations. Our results emphasized the risks of ignoring possibly significant interactions at the isoform level by concentrating just on the canonical isoform and promoting consideration of the impacts of cervical cancer drugs on- and off-target at the isoform level to further research.

bioinformatics↗

bioRxiv2022

Regenerative Agriculture Augments Bacterial Community Structure for a Healthier Soil and Agriculture

Use of chemical fertilization and pesticides not only harm the environment but also have detrimental consequences on human health. In recent years, there has been a major emphasis worldwide on natural agriculture methods. Regenerative agriculture is known across the world as a combination of nature-friendly farming practices such as no-till, cover cropping, crop-rotation, agro-forestry and use of organic home-based/farm-based ingredients to revive soil health. In India, a number of farmers are slowly adopting these practices using home-based mixtures and farmyard manure for soil rejuvenation and pest management. In order to evaluate the efficacy of the regenerative agriculture practices, this study compared conventional and regenerative agriculture plots for their soil bacterial and nutrient profiles. Two crops - ragi and vegetable (tomato/beans), and different lengths ([≤]3 and >5 years) of regenerative practices were additional metrics considered to understand variabilities due to crop-type and period of application. We found that all regenerative practices were effective in bringing about an enrichment for soil bacteria with a more heterogeneous composition. Additionally, the regenerative vegetable (RV) plots had an enhanced representation of Actinobacteriota, Chloroflexi, Cyanobacteria and Patescibacteria in comparison to conventional vegetable (CV) plots and Barren land (BL). Similarly, the regenerative ragi (RR) plots saw higher representation of Firmicutes and Actinobacteriota in comparison to conventional ragi (CR) plots and BL. The RV plots were also found to be enriched for Plant Growth Promoting Rhizobacteria (PGPRs) - Pseudomonas sp., and RR plots were enriched for Bacillus sp., and Mesorhizobium sp., which are known to play significant roles in vegetable and ragi growth respectively. Interestingly, long-term regenerative agriculture was able to support good nutrient composition while enhancing Soil Organic Carbon (SOC) levels. In all, the regenerative agriculture practices were found to be effective in improving bacterial community structure and simultaneously improving soil health. We found that BL soil with eucalyptus plantation showed least bacterial diversity suggesting detrimental impact on soil health.

ecology↗

bioRxiv2022

Analysis of Aedes aegypti microRNAs in response to Wolbachia wAlbB infection and their potential role in mosquito longevity

The mosquito Aedes aegypti is the primary vector of a range of medically important viruses including dengue, Zika, West Nile, yellow fever, and chikungunya viruses. The endosymbiotic bacterium Wolbachia pipientis wAlbB strain is a promising biocontrol agent for blocking viral transmission by Ae. aegypti. To predict the long-term efficacy of field applications, a thorough understanding of the interactions between symbiont, host, and pathogen is required. Wolbachia influence host physiology in a variety of ways including reproduction, immunity, metabolism, and longevity. MicroRNAs (miRNAs) are highly conserved small non-coding RNAs that regulate gene expression in eukaryotes and viruses. A number of miRNAs are known to regulate biological processes in Drosophila and mosquitoes, including facilitating Wolbachia maintenance. We generated the first chromosomal map of Ae. aegypti miRNAs, and compared miRNA expression profiles between a wAlbB-transinfected Ae. aegypti mosquito line and a tetracycline cleared derivative, using deep small RNA-sequencing. We found limited modulation of miRNAs in response to wAlbB infection. Several miRNAs were modulated in response to age, some of which showed greater upregulation in wAlbB-infected mosquitos than in tetracycline cleared ones. By selectively inhibiting some differentially expressed miRNAs, we identified miR-2946-3p and miR-317-3p as effecting mosquito longevity. ImportanceWolbachia is an endosymbiotic bacterium found in about 65% of insect species. It is mostly known for reproductive manipulations of the host, and also blocking replication of positive sense RNA viruses. Transinfection of Wolbachia into Aedes aegypti mosquitoes, which transmit a variety of arboviruses, including dengue virus, has provided a novel biological approach in reducing transmission of arboviruses. To gain a better understanding of Wolbachia-mosquito interactions, we investigated the impact of Wolbachia on the microRNA profile of Ae. aegypti mosquitoes. We produced the first chromosome-level map of Ae. Aegypti miRNAs. We found modulation of microRNAs in mosquitoes due to age, with two miRNAs, 317-3p and 2946-3p, showing significant increase with age. Inhibition of 317-3p and 2946-3p led to reduced mosquito life span in wAlbB-infected mosquitoes. The outcomes provide insights into underlying molecular mechanisms involved in Wolbachia-host interactions.

microbiology↗

bioRxiv2021

A severe form of maternal separation in rat consisting of nineteen-day 6-hour daily separation at unpredictable times minimally affects behavior across lifespan and possibly confers protection against some maladaptive outcomes

Maternal separation (MS), a type of early life stress, has been associated with adverse socioemotional and behavioral outcomes throughout the lifespan across multiple species. Comprehensive longitudinal biobehavioral characterization of MS in rats is sparse and conflicting, warranting more studies. We conducted an MS paradigm involving 6-hour daily separation at unpredictable start times from P2 to P21. We hypothesized this severe form of MS would lead to developmentally emerging maladaptive biobehavioral consequences from juvenile through adult periods compared to Controls (C), especially in social behaviors. We tested: (1) own dam odor preference shortly after weaning; (2) juvenile and adult anxiety-like, sociability, and play behaviors using the light-dark test, three-chambered social interaction test, and video-coded juvenile play behavior; and (3) adult coping behaviors and neuroendocrine response using the forced swim test and blood corticosterone responses. Our results show minimal effects on biobehavioral outcomes across the lifespan. Recently weaned MS male rats had a stronger preference for their dams odor. Juvenile MS females spent more time in rough-and-tumble play than C female rats. No differences in sociability were found in the juvenile or adult periods. MS promoted a decrease in anxiety-like behavior that persisted from juvenile to adult periods. Finally, MS led to deficits in coping behavior in male adults, but basal and reactive corticosterone levels were unaltered by MS. More studies are needed to validate our surprising findings and probe the neural mechanisms underlying some of the observed protective effects. Significance StatementMaternal separation (MS), a type of early life stress, has been shown to lead to short and long-term adverse socioemotional consequences in humans and biobehavioral outcomes in rodents. Available data on MS exposed rats are sparse, conflicting, and often lack longitudinal outcomes. We designed a 6-hour unpredictable daily MS paradigm from postnatal day (P2) to P21 to severely disrupt normal dam-pup interactions. Our results show MS leads to increased preference for own dam odor, persisting reductions in anxiety-like behaviors from juvenile to adulthood, and no effects on sociability. Adverse effects on coping behaviors were uniquely identified in males. The present study warrants reevaluation of the central dogma that MS leads to maladaptive biobehavioral outcomes.

neuroscience↗

bioRxiv2021

EMS-based mutants are useful for enhancing drought tolerance in spring wheat

Sustainable wheat production in drought prone areas can be achieved by developing resilient wheat varieties. In the present study, chemical mutagenesis was used to induce mutations in a cultivated wheat variety NN-Gandum-1. In total, 44 mutants were selected based on their high yield potential for exposing to well-watered (W1) and rainfed (W2) conditions for one season. Then 24 mutants were selected, and were exposed to W1 and W2 regimes. On the basis of least relative reduction in physiological parameters under W2 regime, five mutants were selected for conducting exome capturing assays. In total, 184 SNPs were identified in nine genes (ABC transporter type 1, Aspartic peptidase, Cytochrome P450, transmembrane domain, Heavy metal-associated domain, HMA, NAC domain, NAD (P)-binding domain, S-type anion channel, Ubiquitin-conjugating enzyme E2 and UDP-glucuronosyl/UDP-glucosyltransferase). Maximum number of mutations were observed in chr.2D, which contained mutations in three genes i.e. ABC transporter type 1, NAD (P)-binding domain and UDP-glucuronosyl/UDP-glucosyltransferase which may have a role in conferring drought tolerance. The selected mutants were further tested for studying their biochemical responses under both the regimes for two years. The extent of membrane damage was estimated through malondialdehydeand hydrogen per oxidase and tolerance to drought stress was assessed via antioxidant enzymes in leaves. The selected mutants under drought stress increased the accumulation of proline content, total soluble sugars, total free amino acids, while decreased total chlorophyll content, carotenoids and total soluble protein. Finally, the procedure of narrowing down the number of developed mutants from a large mutation population (>4000) is found useful for exploring the complex trait like drought without compromising yield potential. These mutants can further be explored to understand the genetic circuits of drought tolerance in wheat which will pave the way towards improving livelihood of resource poor farming community mostly relying on cereal food.

plant biology↗

bioRxiv2020

Genetic models suggest single and multiple origins of dihydrofolate reductase mutations in Plasmodium vivax

Pyrimethamine was first introduced for the treatment of malaria in Asia and Africa during the early 1980s, replacing chloroquine, and has become the first line of drugs in many countries. In recent years, development of pyrimethamine resistance in Plasmodium vivax has become a barrier to effective malaria control strategies. Here, we describe the use of meta-barcoded deep amplicon sequencing technology to assess the evolutionary origin of pyrimethamine resistance by analysing the flanking region of dihydrofolate reductase (dhfr) locus. The genetic modelling suggests that 58R and 173L single mutants and 58R/117N double mutants are present on a single lineage; suggesting a single origin of these mutations. The triple mutants (57L/58R/117N, 58R/61M/117N and 58R/117N/173L) share the lineage of 58R/117N, suggesting a common origin. In contrast, the 117N mutant is present on two separate lineages suggesting that there are multiple origins of this mutation. We characterised the allele frequency of the P. vivax dhfr locus. Our results support the view that the single mutation of 117N and double mutations of 58R/117N arise commonly, whereas the single mutation of 173L and triple mutations of 57L/58R/117N, 58R/61M/117N and 58R/117N/173L are less common. Our work will help to inform mitigation strategies for pyrimethamine resistance in P. vivax.

genetics↗

bioRxiv2020

Novel Loss-of-Function Mutations in COCH Cause Autosomal Recessive Nonsyndromic Deafness

COCH is the most abundantly expressed gene in the cochlea. Unsurprisingly, mutations in COCH underly deafness in mice and humans. Two forms of deafness are linked to mutations in COCH, the well-established autosomal dominant nonsyndromic hearing loss, with or without vestibular dysfunction (DFNA9) via a gain-of-function/dominant-negative mechanism, and more recently autosomal recessive nonsyndromic hearing loss (DFNB110) via nonsense variants. Using a combination of targeted gene panels, exome sequencing and functional studies, we identified four novel pathogenic variants (two nonsense variants, one missense and one inframe deletion) in COCH as the cause of autosomal recessive hearing loss in a multi-ethnic cohort. To investigate whether the non-truncating variants exert their effect via a loss-of-function mechanism, we used mini-gene splicing assays. Our data showed both the missense and inframe deletion variants altered RNA-splicing by creating an exon splicing silencer and abolishing an exon splicing enhancer, respectively. Both variants create frameshifts and are predicted to result in a null allele. This study confirms the involvement of loss-of-function mutations in COCH in autosomal recessive nonsyndromic hearing loss, expands the mutational landscape of DFNB110 to include coding variants that alter RNA-splicing, and highlights the need to investigate the effect of coding variants on RNA-splicing.

genetics↗

bioRxiv2020

Structural Basis of SARS-CoV-2 Spike Protein Priming by TMPRSS2

Entry of SARS-CoV-2, etiological agent of COVID-19, in the host cell is driven by the interaction of its spike protein with human ACE2 receptor and a serine protease, TMPRSS2. Although complex between SARS-CoV-2 spike protein and ACE2 has been structurally resolved, the molecular details of the SARS-CoV-2 and TMPRSS2 complex are still elusive. TMPRSS2 is responsible for priming of the viral spike protein that entails cleavage of the spike protein at two potential sites, Arg685/Ser686 and Arg815/Ser816. The present study aims to investigate the conformational details of complex between TMPRSS2 and SARS-CoV-2 spike protein, in order to discern the finer details of the priming of viral spike and to point candidate drug targets. Briefly, full length structural model of TMPRSS2 was developed and docked against the resolved structure of SARS-CoV-2 spike protein with directional restraints of both cleavage sites. The docking simulations showed that TMPRSS2 interacts with the two different loops of SARS-CoV-2 spike protein, each containing different cleavage sites. Key functional residues of TMPRSS2 (His296, Ser441 and Ser460) were found to interact with immediate flanking residues of cleavage sites of SARS-CoV-2 spike protein. Compared to the N-terminal cleavage site (Arg685/Ser686), TMPRSS2 region that interact with C-terminal cleavage site (Arg815/Ser816) of the SARS-CoV-2 spike protein was predicted as relatively more druggable. In summary, the present study provide structural characteristics of molecular complex between human TMPRSS2 and SARS-CoV-2 spike protein and points to the candidate drug targets that could further be exploited to direct structure base drug designing.

bioinformatics↗

bioRxiv2020

Combining rational design and continuous evolution on minimalist proteins that target DNA

We designed MEF to mimic the basic region/helix-loop-helix/leucine zipper (bHLHZ) domain of transcription factors Max and Myc, which bind with high DNA sequence specificity and affinity to the E-box motif (enhancer box, CACGTG). To make MEF, we started with our rationally designed ME47, a hybrid of the Max basic region and E47 HLH, that effectively inhibited tumor growth in a mouse model of breast cancer. ME47, however, displays propensity for instability and misfolding. We therefore sought to improve ME47s structural and functional features. We used phage-assisted continuous evolution (PACE) to uncover "nonrational" changes to complement our rational design. PACE mutated Arg12 that contacts the DNA phosphodiester backbone. We would not have rationally made such a change, but this mutation improved ME47s stability with little change in DNA-binding function. We mutated Cys29 to Ser and Ala in ME47s HLH to eliminate undesired disulfide formation; these mutations reduced E-box binding activity. To compensate, we fused the designed FosW leucine zipper to ME47 to increase the dimerization interface and improve protein stability and E-box targeting activity. This "franken-protein" MEF comprises the Max basic region, E47 HLH, and FosW leucine zipper--plus mutations that arose during PACE and rational design--and is a tractable, reliable protein in vivo and in vitro. Compared with ME47, MEF gives three-fold stronger binding to E-box with four-fold increased specificity for E-box over nonspecific DNA. Generation of MEF demonstrates that combining rational design and continuous evolution can be a powerful tool for designing proteins with robust structure and strong DNA-binding function.

bioengineering↗

bioRxiv2019

Novel metabarcoded DNA sequencing tool for the detection of Plasmodium species in malaria positive patients

Various PCR based methods have been described for the diagnosis of malaria, but most depend on the use of Plasmodium species-specific probes and primers; hence only the tested species are identified and there is limited available data on the true circulating species diversity. Sensitive diagnostic tools and platforms for their use are needed to detect Plasmodium species in both clinical cases and asymptomatic infections that contribute to disease transmission. We have been recently developed for the first time a novel high throughput haemoprotobiome metabarcoded DNA sequencing method and applied it for the quantification of haemoprotozoan parasites (Theleria and Babesia) of livestock. Here, we describe a novel, high throughput method using an Illumina MiSeq platform to demonstrate the proportions of Plasmodium species in metabarcoded DNA samples derived from human malaria patients. Plasmodium falciparum and Plasmodium vivax positive control gDNA was used to prepare mock DNA pools of parasites to evaluate the detection threshold of the assay for each of the two species and to assess the accuracy of proportional quantification. We then applied the assay to malaria-positive human samples to show the species composition of Plasmodium communities in the Punjab province of Pakistan and in the Afghanistan-Pakistan tribal areas. The diagnostic performance of the deep amplicon sequencing method was compared to an immunochromatographic assay that is widely used in the region. Metabarcoded DNA sequencing showed better diagnostic performance, greatly increasing the estimated prevalence of Plasmodium infection. The next-generation sequencing method using metabarcoded DNA has potential applications in the diagnosis, surveillance, treatment, and control of Plasmodium infections, as well as to study the parasite biology.

genetics↗