Biology subjects

Xi, Y.

Publications and source records attributed to Xi, Y..

At least 37 records · Page 2Linked to original sources

bioRxiv2025

Human Cytomegalovirus Infection Reduces an Endogenous Antiviral Fatty Acid by Promoting Host Metabolism

Some viruses, including human cytomegalovirus (HCMV), induce the synthesis of fatty acids and lipids to ensure that the lipid environment of infected cells supports virus replication. HCMV infection broadly reprograms metabolism to ensure central carbon metabolism provides the metabolites required for anabolic synthesis of nucleotides, proteins, and lipids while also meeting the energy demands placed on the infected cells. While HCMV infection increases the levels of most very long chain fatty acids (VLCFA), we found that the levels of erucic acid (EA), a C22:1 monounsaturated VLCFA, are reduced. Treating infected cells with EA disrupted a late step in virus replication, resulting in the release of virions with reduced infectivity. Moreover, we used lipidomics to determine that EA-treated cells had elevated levels of lipids containing a combination of a C22:1 tail and a VLC polyunsaturated fatty acid tail (VLC-PUFA). We demonstrate that fatty acid elongase 5 (ELOVL5) mediated production of VLC-PUFAs is stimulated by HCMV infection. ELOVL5 aided the increase in lipids with C22:1 plus VLC-PUFA tails following EA treatment and reduced the overall level of C22:1 in HCMV-infected cells. Moreover, we found that ELOVL5 mollified EA inhibition of HCMV replication, suggesting ELOVL5 plays a critical role in reducing the level of an endogenous FA with antiviral properties. Our study provides insight into how infection may increase the synthesis of an antiviral metabolite or FA and how the virus may evade their antiviral effect by promoting their metabolism.

microbiology↗

bioRxiv2025

Acquired resistance to sotorasib in mutant NSCLC is vulnerable to PI3K-mTOR pathway inhibition mediated by 4E-BP1 regulator of cap-dependent translation

Sotorasib and adagrasib have shown significant efficacy in KRASG12C mutant NSCLC; however, acquired resistance (AR) occurs within 6-12 months. While some resistance arises from new mutations, over half of the resistant cases lack identifiable genomic alterations. We hypothesize that resistance is driven by signaling network rewiring, creating new therapeutic vulnerabilities. To investigate AR mechanisms, multiple AR models, including cell lines, PDXs, CDXs, and PDXOs, were developed. H23AR and H358AR cells displayed >600-fold and 200-fold; and PDXO303AR and PDXO314AR organoids exhibited >300-fold and >100-fold resistance to sotorasib, respectively; however, no additional mutations in KRAS or other potential genetic alterations were identified. The AR cells and PDXOs also showed comparable resistance to adagrasib. Distinct protein signatures associated with KRAS reactivation, mTORC1 signaling upregulation, and PI3K/AKT/mTOR pathway activation were identified in TC303AR & TC314AR PDXs. PI3K protein levels were significantly elevated in AR PDXs, H23AR, and H358AR cells. Pharmacological inhibition of PI3K with copanlisib or genetic knockout via CRISPR-Cas9 restored sotorasib sensitivity, suppressed colony formation, and inhibited downstream effectors, including p-AKT, p-mTOR, p-S6, p70S6K, p-GSK3{beta}, and p-PRAS40 in AR cells. Copanlisib also sensitized both acquired and primary resistant PDXOs and synergized with sotorasib in restoring drug sensitivity. p4E-BP1 was significantly upregulated in H23AR and H358AR cells, which is suppressed by copanlisib. The level of p4E-BP1 expression was correlated with Sotorasib sensitivity in PI3K knockout clones, where the most sensitive clone displayed reduced or no p4E-BP1 expression. CRISPR-Cas9-mediated knockout of 4E-BP1, either alone or in combination with PI3K knockout, dramatically restored sotorasib sensitivity to levels comparable to parental cells. Suppression of 4E-BP1 hyperphosphorylation required dual inhibition of mTORC1 and mTORC2, and treatment with AZD8055 or sapanisertib (mTORC1/2 dual inhibitors) significantly dephosphorylated 4E-BP1 and restored sotorasib sensitivity in resistant cells and PDXOs. In PDX, CDX, and xenograft models in vivo, the combination of sotorasib with either copanlisib or sapanisertib resulted in robust, synergistic, and durable tumor regression at well-tolerated doses. These findings showed the critical role of PI3K/mTOR signaling as a bypass mechanism of resistance to KRASG12C inhibitors. We conclude that mTORC1/2 mediated inhibition of p4E-BP1 and combination strategies targeting this pathway effectively overcome acquired resistance to KRASG12C inhibitors in NSCLC.

cancer biology↗

bioRxiv2025

Human cytomegalovirus promotes de novo PC synthesis during early virus replication

Human cytomegalovirus (HCMV) infection reprograms metabolism, including lipid synthesis. While several metabolite-related pathways have been demonstrated to have altered activity in infected cells, the alteration of lipid-related pathways by HCMV has not been examined beyond fatty acid synthesis and elongation. In this study, we addressed this lack of understanding by focusing on phosphatidylcholine (PC), a class of lipids we previously showed is increased by HCMV infection in human foreskin fibroblasts. Here, we found that HCMV infection increases the abundance of PCs in several different fibroblasts and, similarly, in endothelial and epithelial cells. Additionally, HCMV elevates PC levels regardless of the level of confluency, type of growth medium, and presence of serum. Next, we investigated if HCMV alters the activity in the three PC synthesis pathways. We demonstrate that HCMV infection promotes the activity in the de novo PC synthesis pathway using a 13C-choline isotopic tracer and liquid chromatography high resolution tandem mass spectrometry (LC-MS/MS). Infection did not alter the activity in the other two pathways. Moreover, we examined the kinetics of PC remodeling by HCMV and found that the de novo synthesis pathway is promoted and the PC lipidome shifts 24 hours post infection. That led us to examining if the early stages of replication are sufficient to alter PC levels. After inhibiting late virus replication, we found that HCMV alters the PC lipidome independent of late gene expression. Overall, this work suggests that an immediate-early or early viral protein promotes the reprogramming of host lipid metabolism to ensure the synthesis of a lipidome necessary to support HCMV replication. IMPORTANCEHuman cytomegalovirus (HCMV) is a common herpesvirus that establishes a lifelong and persistent infection in its human host (1). HCMV infection in most people does not cause overt disease (1). However, in immunocompromised individuals, severe CMV-associated disease can lead to permanent disabilities and even death (1, 2). Additionally, congenital CMV is the leading infectious cause of birth defects (3, 4). Viruses have evolved to hijack host metabolic pathways to facilitate their replication cycle. In this study, we determine that HCMV promotes the activity in the de novo pathway of phosphatidylcholine (PC) synthesis. We demonstrate that the activity in the other PC synthesis pathways, the PEMT and Lands cycle, is unaltered by HCMV infection. Moreover, we found that HCMV infection alters metabolic activity to increase the PC lipidome before 48 hpi. Additionally, we demonstrate that changes in PC lipids during virus replication is independent of late gene expression. Together, our findings demonstrate that infection promotes the de novo PC pathway to increase PC lipids during the early stages of virus replication.

microbiology↗

bioRxiv2025

Characterization of Woodsmoke Generated in the Air Pollution Exposure Lab and Comparison to Diesel Exhaust

To address the increasing concern of woodsmoke (WS) and better understand its effects on human health, a woodsmoke generation system was built in the Air Pollution Exposure Laboratory to facilitate future controlled human exposure studies. Two different woodsmoke conditions, flaming (WSFL) and smoldering (WSSM), were generated, and PM2.5 concentrations of approximately 500 g/m3 were achieved. The woodsmoke produced using the system was characterized in this study and compared with diesel exhaust (DE) generated and collected at the same facility. Within the gas phase generated by the pollutants, WS showed slight increases in CO and CO2 compared to filtered air (FA), while DE contained significantly higher levels of NOx, CO2, and total volatile organic compounds compared to FA. The WS aerosols were comprised of approximately 98% organics, 0.6% NH4, 0.9% NO3, and 0.2% SO4. Among the organic species, the CHO1 and CHOgt1 families encompassed around 60%, which was higher than the fraction of oxygenated families in DE aerosols. Moreover, the WS aerosols had higher concentrations of Cd compared to the DE aerosols. Greater oxidative potentials were also observed for WSFL and WSSM compared to DE, with DTT consumption rates normalized to the PM mass being 0.0099 and 0.0090 nmol/min/g, respectively. The difference in the compositions and properties of WS and DE suggests that it is critical to conduct further studies on how these pollutants can affect health differently.

pharmacology and toxicology↗

bioRxiv2024

Pseudohypoxia-stabilized HIF2α transcriptionally inhibits MNRR1, a druggable target in MELAS

AbstractThe observation that amounts of the mitochondrial regulator MNRR1 (CHCHD2, AAG10, PARK22) are reduced in several pathologies, and that restoration of its level normalizes the pathological phenotype, prompted a search for compounds that could increase MNRR1 levels. High throughput screening of a 2400-compound drug and natural products library uncovered the antifungal drug nitazoxanide and its metabolite tizoxanide as effective enhancers of MNRR1 transcription. Using the mitochondrial disease MELAS (in which various mixtures, called heteroplasmy, of wild-type and mutant mitochondrial DNA (mtDNA) coexist) as a test, we showed that treating a cybrid MELAS model with tizoxanide could restore cellular respiration, enhance mitophagy, and, importantly, shift heteroplasmy toward more wild-type mtDNA. Furthermore, in MELAS patient fibroblasts, the compound could improve mitochondrial biogenesis, enhance autophagy, and protect the fibroblasts from LPS-induced inflammation. Chemical activation of MNRR1 is thus a potential strategy to improve mitochondrial deficits seen in MELAS. Investigation of the mechanism by which MNRR1 is reduced identified that two factors compete to regulate transcription at the MNRR1 promoter - RBPJ{kappa}, which stimulates it, and HIF2, which inhibits it. In MELAS cells there is a pseudohypoxic state that stabilizes HIF2, leading to transcriptional inhibition of MNRR1. Nitazoxanide reduces the levels of HIF2 by increasing the levels of PHD3, the prolyl hydroxylase that degrades HIF2.

molecular biology↗

bioRxiv2024

DNA damage response signatures are associated with frontline chemotherapy response and routes of tumor evolution in extensive stage small cell lung cancer

IntroductionA hallmark of small cell lung cancer (SCLC) is its recalcitrance to therapy. While most SCLCs respond to frontline therapy, resistance inevitably develops. Identifying phenotypes potentiating chemoresistance and immune evasion is a crucial unmet need. Previous reports have linked upregulation of the DNA damage response (DDR) machinery to chemoresistance and immune evasion across cancers. However, it is unknown if SCLCs exhibit distinct DDR phenotypes. MethodsTo study SCLC DDR phenotypes, we developed a new DDR gene analysis method and applied it to SCLC clinical samples, in vitro, and in vivo model systems. We then investigated how DDR regulation is associated with SCLC biology, chemotherapy response, and tumor evolution following therapy. ResultsUsing multi-omic profiling, we demonstrate that SCLC tumors cluster into three DDR phenotypes with unique molecular features. Hallmarks of these DDR clusters include differential expression of DNA repair genes, increased replication stress, and heightened G2/M cell cycle arrest. SCLCs with elevated DDR phenotypes exhibit increased neuroendocrine features and decreased "inflamed" biomarkers, both within and across SCLC subtypes. Treatment naive DDR status identified SCLC patients with different responses to frontline chemotherapy. Tumors with initial DDR Intermediate and DDR High phenotypes demonstrated greater tendency for subtype switching and emergence of heterogeneous phenotypes following treatment. ConclusionsWe establish that SCLC can be classified into one of three distinct, clinically relevant DDR clusters. Our data demonstrates that DDR status plays a key role in shaping SCLC phenotypes, chemotherapy response, and patterns of tumor evolution. Future work targeting DDR specific phenotypes will be instrumental in improving patient outcomes.

cancer biology↗

bioRxiv2024

CIB2 as a Ca2+ Sensor for Auditory Mechano-Electrical Transduction and Linked to Genetic-Heterogeneity of TMC1 in Hearing Loss

Non-syndromic sensorineural hearing loss is characterized by genetic heterogeneity, leading to potential clinical misdiagnosis. TMC1, a unique causative gene associated with deafness, exhibits variants with autosomal dominant and recessive inheritance patterns. TMC1 codes for the transmembrane channel-like 1 (TMC1), a key component of the mechano-electrical transduction (MET) machinery for hearing. However, the molecular mechanism of Ca2+ regulation in MET, which is essential for sound perception, remains unclear. CIB2, another MET component associated with deafness, can bind with calcium and may play a role in MET gating. Our study reveals that the TMC1-CIB2 complex undergoes a Ca2+-induced conformational change, highlighting the crucial role of Ca2+ in MET. We identified a vertebrate-specific binding site on TMC1, named CR3, that interacts with apo CIB2, with the binding interface linked to hearing loss. Using an in-vivo animal model, we demonstrated that disruption of the calcium-sensing site of CIB2 perturbs the MET channel conductivity, confirming its role as a Ca2+ sensor for MET. Additionally, after systematically analyzing the hearing-loss variants, we observed that dominant mutations of TMC1 are often located near the ion pore or at the binding interfaces with the Ca2+ sensor CIB2. This provides a detailed mechanism of the genetic heterogeneity of TMC1 in hearing loss at an atomic level.

molecular biology↗

bioRxiv2024

SMARCA4 mutation induces tumor cell-intrinsic defects in enhancer landscape and resistance to immunotherapy

Cancer genomic studies have identified frequent alterations in components of the SWI/SNF (SWItch/Sucrose Non- Fermenting) chromatin remodeling complex including SMARCA4 and ARID1A. Importantly, clinical reports indicate that SMARCA4-mutant lung cancers respond poorly to immunotherapy and have dismal prognosis. However, the mechanistic basis of immunotherapy resistance is unknown. Here, we corroborated the clinical findings by using immune-humanized, syngeneic, and genetically engineered mouse models of lung cancer harboring SMARCA4 deficiency. Specifically, we show that SMARCA4 loss caused decreased response to anti-PD1 immunotherapy associated with significantly reduced infiltration of dendritic cells (DCs) and CD4+ T cells into the tumor microenvironment (TME). Mechanistically, we show that SMARCA4 loss in tumor cells led to profound downregulation of STING, IL1{beta} and other components of the innate immune system as well as inflammatory cytokines that are required for efficient recruitment and activity of immune cells. We establish that this deregulation of gene expression is caused by cancer cell-intrinsic reprogramming of the enhancer landscape with marked loss of chromatin accessibility at enhancers of genes involved in innate immune response such as STING, IL1{beta}, type I IFN and inflammatory cytokines. Interestingly, we observed that transcription factor NF-{kappa}B binding motif was highly enriched in enhancers that lose accessibility upon SMARCA4 deficiency. Finally, we confirmed that SMARCA4 and NF-{kappa}B co-occupy the same genomic loci on enhancers associated with STING and IL1{beta}, indicating a functional interplay between SMARCA4 and NF-{kappa}B. Taken together, our findings provide the mechanistic basis for the poor response of SMARCA4-mutant tumors to anti-PD1 immunotherapy and establish a functional link between SMARCA4 and NF-{kappa}B on innate immune and inflammatory gene expression regulation.

immunology↗

bioRxiv2024

Ferroptosis mediates the progression of hyperuricemic nephropathy by activating RAGE signaling

Hyperuricemic nephropathy (HN) represents a prevalent complication arising from hyperuricemia, typified by tubular dysfunction, inflammation, and progressive renal fibrosis, whose pathogenic mechanisms remain enigmatic. Ferroptosis, a newly elucidated iron-dependent form of regulated cell death, plays a role in various disease states. However, its involvement in HN has seldom been explored. In this study, we observed indications of ferroptosis in the renal tissues of urate oxidase knockout (UOX-/-) mice, a model of hyperuricemia, as evidenced by increased iron deposition and reduced expression of glutathione peroxidase 4 (GPX4). These findings suggest a substantial role of ferroptosis in the pathogenesis of HN. To further explore this hypothesis, UOX-/- mice were administered Ferrostatin-1, a known inhibitor ferroptosis. This treatment markedly ameliorated tubular injury, necrosis, and inflammatory cell infiltration, mitigated renal fibrosis, reinstated the expression of proteins associated with ferroptosis in renal tissues, and reduced iron overload, lipid peroxidation, and mitochondrial damage in UOX-/- mice. Additionally, we found that receptor for advanced glycation end products (RAGE) propagates ferroptosis-induced renal injury, inflammation and fibrosis, albeit without directly facilitating ferroptosis. Finally, ferroptosis and RAGE upregulation were validated in renal tissues of patients with hyperuricemia-related kidney disease. Collectively, our research elucidates the critical contribution of ferroptosis to HN pathogenesis, indicating that therapeutic strategies targeting ferroptosis and the related RAGE signaling may offer novel therapeutic approaches for managing this condition.

ecology↗

bioRxiv2024

Bioengineering a plant NLR immune receptor with a robust binding interface towards a conserved fungal pathogen effector

Bioengineering of plant immune receptors has emerged as a key strategy for generating novel disease resistance traits to counteract the expanding threat of plant pathogens to global food security. However, current approaches are limited by rapid evolution of plant pathogens in the field and may lack durability when deployed. Here, we show that the rice nucleotide-binding, leucine-rich repeat (NLR) immune receptor Pik-1 can be engineered to respond to a conserved family of effectors from the multihost blast fungus pathogen Magnaporthe oryzae. We switched the effector binding and response profile of the Pik NLR from its cognate rice blast effector AVR-Pik to the host-determining factor Pwl2 by installing a putative host target, OsHIPP43, in place of the native integrated HMA domain (generating Pikm-1OsHIPP43). This chimeric receptor also responded to other PWL alleles from diverse blast isolates. The crystal structure of the Pwl2/OsHIPP43 complex revealed a multifaceted, robust interface that cannot be easily disrupted by mutagenesis, and may therefore provide durable, broad resistance to blast isolates carrying PWL effectors in the field. Our findings highlight how the host targets of pathogen effectors can be used to bioengineer new recognition specificities that have more robust properties compared to naturally evolved disease resistance genes.

plant biology↗

bioRxiv2023

YAP1 status defines two intrinsic subtypes of LCNEC with distinct molecular features and therapeutic vulnerabilities

Large cell neuroendocrine carcinoma (LCNEC) is a high-grade neuroendocrine malignancy that, like the more common small cell lung cancer (SCLC), is associated with an absence of druggable oncogenic driver mutations, a clinically aggressive disease course, and dismal prognosis. In contrast to SCLC, however, there is little evidence to guide optimal treatment strategies which are, instead, often adapted from SCLC and non-small cell lung cancer (NSCLC) approaches. While there have been some efforts to describe the molecular landscape of LCNEC, to date there are few links between distinct biologic phenotypes of LCNEC and therapeutic vulnerabilities. Here, we demonstrate that the presence or absence of the transcription factor YAP1 distinguishes two roughly equal subsets of LCNEC. The YAP1-high subset is mesenchymal and inflamed and characterized, alongside TP53 mutations, by co-occurring alterations in CDKN2A/B and SMARCA4. Therapeutically, the YAP1-high subset demonstrates vulnerability to MEK and AXL targeting strategies, including a novel preclinical AXL CAR-T cell, as well as predicted vulnerability to SMARCA2 degraders and CDK4/6 inhibitors. Meanwhile, the YAP1-low subset is epithelial and immune-cold and more commonly features TP53 and RB1 co-mutations, similar to those observed in pure SCLC. Notably, the YAP1-low subset is also characterized by expression of SCLC subtype-defining transcription factors -especially ASCL1 and NEUROD1 - and, as expected given its transcriptional similarities to SCLC, exhibits putative vulnerabilities reminiscent of SCLC, including Delta-like ligand 3 (DLL3) and CD56 targeting, as with novel preclinical DLL3 and CD56 CAR T-cells, and DNA damage repair (DDR) inhibition. These findings highlight the potential for YAP1 to guide the first personalized treatment strategies for LCNEC.

cancer biology↗

bioRxiv2023

Airway secretory cell-derived p63+ progenitors contribute to alveolar regeneration after sterile lung injury

Lung injury activates epithelial stem or progenitor cells for alveolar repair and regeneration. However, the origin and fate of injury-induced progenitors are poorly defined. Here, we report that p63-expressing progenitors emerge upon bleomycin-induced lung injury. These p63+ progenitors proliferate rapidly and differentiate into alveolar type 1 (AT1) and type 2 (AT2) cells through distinct trajectories. Dual recombinase-mediated sequential genetic lineage tracing reveals that p63+ progenitors originate from airway secretory cells and subsequently generate alveolar cells. Functionally, p63 activation is required for efficient alveolar regeneration from secretory cells. Our study identifies a secretory cell-derived p63+ progenitor that contributes to alveolar repair, indicating a potential therapeutic avenue for lung regeneration after injury.

cell biology↗

bioRxiv2023

Deficiency for scavenger receptors Stabilin-1 and Stabilin-2 leads to age-dependent renal and hepatic depositions of fasciclin domain proteins TGFBI and Periostin in mice

BackgroundStabilin-1 and Stabilin-2 are two major scavenger receptors of liver sinusoidal endothelial cells that mediate removal of diverse molecules from the plasma. Double-knockout mice (Stab-DKO) develop impaired kidney function and a decreased lifespan, while single Stabilin deficiency or therapeutic inhibition ameliorates atherosclerosis and Stab1-inhibition is subject of clinical trials in immuno-oncology. Although POSTN and TFGBI have recently been described as novel Stabilin ligands, the dynamics and functional implications of these ligands have not been comprehensively studied. MethodsImmunofluorescence, Western Blotting and Simple Western as well as in situ hybridization (RNAScope) und qRT-PCR were used to analyze transcription levels and tissue distribution of POSTN and TGFBI in Stab-KO mice. Stab-POSTN-Triple deficient mice were generated to assess kidney and liver fibrosis and function in young and aged mice. ResultsTGFBI and POSTN protein accumulated in kidney and liver tissue in Stab-DKO mice during aging despite unchanged transcriptional levels. Stab-POSTN-Triple KO mice showed glomerulofibrosis and a reduced lifespan comparable to Stab-DKO mice. However, alterations of the glomerular diameter and vascular density were partially normalized in Stab-POSTN-Triple KO. ConclusionTGFBI and POSTN are Stabilin-ligands that are deposited in an age-dependent manner in the kidneys and liver due to insufficient scavenging in the liver. Functionally, POSTN appears to partially contribute to the observed renal phenotype in Stab-DKO mice. This study provides details on downstream effects how how Stabilin dysfunction affects distant organs on a molecular and functional level.

molecular biology↗

bioRxiv2023

MNRR1 activation by nitazoxanide abrogates lipopolysaccharide- induced preterm birth in mice

Intra-amniotic inflammation leading to preterm birth is one of the leading causes of neonatal morbidity and mortality. We recently found that the mitochondrial levels of MNRR1 (Mitochondrial Nuclear Retrograde, Regulator 1; also called CHCHD2, AAG10, or PARK22), an important bi-organellar regulator of cellular function, are reduced in the context of inflammation and that both genetic and pharmacological increase in MNRR1 levels can counter the inflammatory profile. We show here that nitazoxanide, a clinically-approved drug, is an activator of MNRR1 and prevents preterm birth in a well-characterized murine model caused by intra-amniotic lipopolysaccharide (LPS) injection. HighlightsO_LINitazoxanide exerts anti-inflammatory functions via activation of MNRR1. C_LIO_LIOral administration of nitazoxanide prevents preterm birth in mouse model of intra-intraamniotic LPS-induced inflammation. C_LI

immunology↗

bioRxiv2022

Magnesium and the magnesium transporter UEX regulate sleep via Ca2+-dependent CREB signaling and a CNK-ERK pathway

Magnesium and its related preparations are already in medical use and have recognized therapeutic effects on sleep disorders. However, its underlying molecular mechanisms remain unclear. Here, using Drosophila as a model, we found that RNAi-mediated knockdown of Uex, the homologous gene of magnesium transporters of the Cyclin M family (CNNM) causes increased daily total sleep. Ectopic-expression of CNNM1 can rescue the sleep phenotype in Uex knockdown flies. UEX exhibits rhythmic oscillations in the brain and affects the efflux of cellular Mg2+. Knockdown of Uex in the nervous system influences Ca2+-mediated CREB signaling and neuroplasticity. Additionally, Uex physically interacts with CNK, the upstream regulator of ERK pathway. Similar effects on sleep are observed with knockdown of Cnk in flies. We propose that the UEX regulates sleep through its downstream Ca2+-dependent CREB signaling and a CNK-ERK pathway. Our findings may provide new insight into mechanisms of magnesium and magnesium transporter related sleep disorder.

genetics↗

bioRxiv2022

LabGym: A versatile computational tool for automatic quantification of user-defined animal behaviors

Quantifying animal behavior is important for many branches of biological research. Current computational tools for behavioral quantification typically rely on a few pre-defined, simplified features to identify a behavior. However, such an approach restricts the information used and the tools applicability to a limited range of behavior types or species. Here we report a new tool, LabGym, for quantifying animal behaviors without such limitations. Combining a novel approach for effective evaluation of animal motion with customizable convolutional recurrent networks for capturing spatiotemporal details, LabGym provides holistic behavioral assessment and accurately identify user-defined animal behaviors without restrictions on behavior types or animal species. It then provides quantitative measurements of each behavior, which quantify the behavior intensity and the body kinematics during the behavior. LabGym requires neither any intermediate step for processing features that causes information loss nor programming knowledge from users for post-hoc analysis. It tracks multiple animals simultaneously in various experimental settings for high-throughput and versatile analysis. It also provides users a way to generate visualizable behavioral datasets that are valuable resources for the research community. We demonstrate its efficacy in capturing subtle behavioral changes in animals ranging from soft-bodied invertebrates to mammals.

animal behavior and cognition↗

bioRxiv2021

MicroRNA-like snoRNA-derived RNAs (sdRNAs) promote castration resistant prostate cancer

We have identified 38 specifically excised, differentially expressed snoRNA fragments (sdRNAs) in TCGA prostate cancer (PCa) patient samples as compared to normal prostate controls. SnoRNA-derived fragments sdRNA-D19b and -A24 emerged among the most differentially expressed and were selected for further experimentation. We found that overexpression of either sdRNA significantly increased PC3 (a well-established model of castration-resistant prostate cancer (CRPC)) cell proliferation, and that sdRNA-D19b overexpression also markedly increased the rate of PC3 cell migration. In addition, both sdRNAs provided drug-specific resistances with sdRNA-D19b levels correlating with paclitaxel resistance and sdRNA-24A conferring dasatinib resistance. In silico and in vitro analyses revealed that two established PCa tumor suppressor genes, CD44 and CDK12, represent targets for sdRNA-D19b and sdRNA-A24 respectively. This outlines a biologically coherent mechanism by which sdRNAs downregulate tumor suppressors in AR-PCa to enhance proliferative and metastatic capabilities and to encourage chemotherapeutic resistance. Aggressive proliferation, rampant metastasis, and recalcitrance to chemotherapy are core characteristics of CRPC that synergize to produce a pathology that ranks 2nd in cancer-related deaths for men. This study defines sdRNA-D19b and -A24 as contributors to AR-PCa potentially providing novel biomarkers and therapeutic targets of use in PCa clinical intervention.

cancer biology↗

bioRxiv2021

The p97-UBXD8 complex modulates ER-Mitochondria contact sites by modulating membrane lipid saturation and composition

The intimate association between the endoplasmic reticulum (ER) and mitochondrial membranes at ER-mitochondria contact sites serves as a platform for several critical cellular processes, in particular lipid synthesis. Enzymes involved in lipid biosynthesis are enriched at contacts and membrane lipid composition at contacts is distinct relative to surrounding membranes. How contacts are remodeled and the subsequent biological consequences of altered contacts such as perturbed lipid metabolism remains poorly understood. Here we show that the p97 AAA-ATPase and its ER-tethered ubiquitin-X domain adaptor 8 (UBXD8) regulate the prevalence of ER-mitochondria contacts. The p97-UBXD8 complex localizes to contacts and loss of this complex increases contacts in a manner that is dependent on p97 catalytic activity. Quantitative proteomics of purified contacts demonstrates alterations in proteins regulating lipid metabolism upon loss of UBXD8. Furthermore, lipidomics studies indicate significant changes in distinct lipid species in UBXD8 knockout cells. We show that loss of p97-UBXD8 results in perturbed contacts due to an increase in membrane lipid saturation via SREBP1 and the lipid desaturase SCD1. Aberrant contacts in p97-UBXD8 loss of function cells can be rescued by supplementation with unsaturated fatty acids or overexpression of SCD1. Perturbation of contacts and inherent lipid synthesis is emerging as a hallmark to a variety of human disorders such as neurodegeneration. Notably, we find that the SREBP1-SCD1 pathway is negatively impacted in the brains of mice with p97 mutations that cause neurodegeneration. Our results suggest that contacts are exquisitely sensitive to alterations to membrane lipid composition and saturation in a manner that is dependent on p97-UBXD8.

cell biology↗