Biology subjects

Sandhu, A.

Publications and source records attributed to Sandhu, A..

7 recordsLinked to original sources

bioRxiv2026

Multi-Omic Analyses of Dietary Fatty Acid-Microbe-Host Interactions Reveal Metaorganismal Lipid Metabolic Crosstalk Impacting Cardiometabolic Disease

Following a meal, our gut microbiome and human cells collaborate via metaorganismal metabolic circuits to produce diverse nutrient metabolites that systemically circulate to influence health and disease. Although there are now several examples of bacterial fiber-, amino acid-, and micronutrient-derived metabolites impacting cardiometabolic disease, very little is known in regards to how diet-microbe-host interactions impact lipid homeostasis. Here we address this by defining dietary fatty acid substrate availability in germ-free versus conventionally-raised mice coupled to deep multi-omic metabolic phenotyping. Our data demonstrate that the effects of dietary saturated (SFA), monounsaturated (MUFA), and polyunsaturated fatty acids (PUFA) on the host lipidome, transcriptome, proteome and metabolome are uniquely impacted by resident microbiota. Also, the hepatic levels of both pro-inflammatory and pro-resolving lipid mediators are strongly influenced by dietary fatty acid-microbe interactions. This study presents a unique resource to the nutrition and metabolism research community to advance our understanding of metaorganismal lipid metabolism. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=104 SRC="FIGDIR/small/705588v1_ufig1.gif" ALT="Figure 1"> View larger version (50K): org.highwire.dtl.DTLVardef@4fc7e3org.highwire.dtl.DTLVardef@1cc1dc8org.highwire.dtl.DTLVardef@1b7648dorg.highwire.dtl.DTLVardef@12a8088_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOGRAPHICAL ABSTRACTC_FLOATNO C_FIG

biochemistry↗

bioRxiv2024

The microtubule regulator EFA-6 forms spatially restricted cortical foci dependent on its intrinsically disordered region and interactions with tubulins

Microtubules (MTs) are dynamic components of the cytoskeleton and play essential roles in morphogenesis and maintenance of tissue and cell integrity. Despite recent advances in understanding MT ultrastructure, organization, and growth control, how cells regulate MT organization at the cell cortex remains poorly understood. The EFA-6/EFA6 proteins are recently identified membrane-associated proteins that inhibit cortical MT dynamics. Here, combining visualization of endogenously tagged C. elegans EFA-6 with genetic screening, we uncovered tubulin-dependent regulation of EFA-6 patterning. In the mature epidermal epithelium, EFA-6 forms punctate foci in specific regions of the apical cortex, dependent on its intrinsically disordered region (IDR). We further show the EFA-6 IDR is sufficient to form biomolecular condensates in vitro. In screens for mutants with altered GFP::EFA-6 localization, we identified a novel gain-of-function (gf) mutation in an -tubulin tba-1 that induces ectopic EFA-6 foci in multiple cell types. tba-1(gf) animals exhibit temperature-sensitive embryonic lethality, which is partially suppressed by efa-6(lf), indicating the interaction between tubulins and EFA-6 is important for normal development. TBA-1(gf) shows reduced incorporation into filamentous MTs but has otherwise mild effects on cellular MT organization. The ability of TBA-1(gf) to trigger ectopic EFA-6 foci formation requires {beta}-tubulin TBB-2 and the chaperon EVL-20/Arl2. The tba-1(gf)-induced EFA-6 foci display slower turnover, contain the MT-associated protein TAC-1/TACC, and require the EFA-6 MTED. Our results reveal a novel crosstalk between cellular tubulins and cortical MT regulators in vivo. HighlightsO_LIThe MT regulator EFA-6 forms spatially restricted punctate cortical foci C_LIO_LIThe EFA-6 N-terminal intrinsically disordered region (IDR) is essential for the formation of cortical foci in vivo and is sufficient for droplet formation in vitro C_LIO_LITubulins regulate formation of EFA-6 foci via the EFA-6 MT elimination domain C_LIO_LIEFA-6 foci induced by altered tubulin heterodimer function display reduced turnover and recruit TAC-1/TACC C_LI

cell biology↗

bioRxiv2023

The RAD51 paralogue HvXRCC2 regulates meiosis and recombination in barley

Using a positional candidate-gene approach we show that semi-sterile desynaptic8 mutants are associated with deletions in or complete knockout of the barley homolog of XRCC2 (X-Ray Repair Cross Complementing 2). In barley XRCC2 mutants, the initial meiotic progression is normal, albeit with a small delay in initiation, with completion of synapsis. However, the absence of HvXRCC2 subsequently leads to a dramatic reduction in the number of crossovers, chromosome mis-segregation, and infertility, suggesting that HvXRCC2 plays a major role in recombination. This mutant phenotype is congruent with that reported in mammalian studies but contrasts with the XRCC2 mutant in Arabidopsis which is fertile, exhibits normal chromosome pairing and correct chromosome segregation, and is associated with an increased rate of crossovers. This indicates that the XRCC2 mutant phenotype in Arabidopsis is not representative of all plants and that XRCC2 is not a good candidate for the modulation of recombination in barley. HighlightThe mutants of the barley homolog of XRCC2 exhibit delays in replication leading to defective meiosis, altered RAD51 orthologue behaviour, and significant reduction in the number of crossovers as in canonical mammalian XRCC2 mutants but unlike those in Arabidopsis.

plant biology↗

bioRxiv2022

An intranasal stringent response vaccine targeting dendritic cells as a novel adjunctive therapy against tuberculosis

Lengthy tuberculosis (TB) treatment is required to address the ability of a subpopulation of persistent Mycobacterium tuberculosis (Mtb) to remain in a non-replicating, antibiotic-tolerant state characterized by metabolic remodeling, including induction of the RelMtb-mediated stringent response. We developed a novel therapeutic DNA vaccine construct involving fusion of the relMtb gene with the immature dendritic cell-targeting gene encoding chemokine MIP-3/CCL20. To augment mucosal immune responses, intranasal delivery was also evaluated. We found that the intramuscular MIP-3/relMtb (fusion) vaccine potentiates isoniazid activity more than a similar DNA vaccine expressing relMtb alone in a chronic TB mouse model (absolute reduction of Mtb burden: 0.63 log10 colony-forming units, P=0.0001), inducing pronounced Mtb-protective immune signatures. The intranasal fusion vaccine, an approach combining relMtb fusion to MIP-3 and intranasal delivery, demonstrated the greatest therapeutic effect compared to each approach alone, as evidenced by robust Th1 and Th17 responses systemically and locally and the greatest mycobactericidal activity when combined with isoniazid (absolute reduction of Mtb burden: 1.13 log10, P<0.0001, when compared to the intramuscular vaccine targeting relMtb alone). This DNA vaccination strategy may be a promising adjunctive approach combined with standard therapy to shorten curative TB treatment, and also serve as proof-of-concept for treating other chronic infections.

immunology↗

bioRxiv2020

Chronic IL-1 exposure drives LNCaP cells to evolve androgen and AR independence

Chronic inflammation promotes prostate cancer (PCa) initiation and progression. We previously reported that acute intereluekin-1 (IL-1) exposure represses androgen receptor (AR) accumulation and activity, providing a possible mechanism for IL-1-mediated development of androgen- and AR-independent PCa. Given that acute inflammation is quickly resolved, and chronic inflammation is, instead, co-opted by cancer cells to promote tumorigenicity, we set out to determine if chronic IL-1 exposure leads to similar repression of AR and AR activity observed for acute IL-1 exposure and to determine if chronic IL-1 exposure selects for androgen- and AR- independent PCa cells. We generated isogenic sublines from LNCaP cells chronically exposed to IL-1 or IL-1{beta}. Cells were treated with IL-1, IL-1{beta}, TNF or HS-5 bone marrow stromal cells conditioned medium to assess cell viability in the presence of cytotoxic inflammatory cytokines. Cell viability was also assessed following serum starvation, AR siRNA silencing and enzalutamide treatment. Finally, RNA sequencing was performed for the IL-1 sublines. MTT, RT-qPCR and western blot analysis show that the sublines evolved resistance to inflammation- induced cytotoxicity and intracellular signaling and evolved reduced sensitivity to siRNA- mediated loss of AR, serum deprivation and enzalutamide. Differential gene expression reveals that canonical AR signaling is aberrant in the IL-1 sublines, where the cells show constitutive PSA repression and basally high KLK2 and NKX3.1 mRNA levels and bioinformatics analysis predicts that pro-survival and pro-tumorigenic pathways are activated in the sublines. Our data provide evidence that chronic IL-1 exposure promotes PCa cell androgen and AR independence and, thus, supports CRPCa development.

cancer biology↗

bioRxiv2019

LNISKS: Reference-free mutation identification for large and complex crop genomes

Mutation discovery is often key to the identification of genes responsible for major phenotypic traits. In the context of bulked segregant analysis, common reference-based computational approaches are not always suitable as they rely on a genome assembly which may be incomplete or highly divergent from the studied accession. Reference-free methods based on short sequences of length k (k-mers), such as NIKS, exploit redundancy of information across pools of recombinant genomes. Building on concepts from NIKS we introduce LNISKS, a mutation discovery method which is suited for large and repetitive crop genomes. In our experiments, it rapidly and with high confidence, identified mutations from over 700 Gbp of bread wheat genomic sequence data. LNISKS is publicly available at https://github.com/rsuchecki/LNISKS.

bioinformatics↗

bioRxiv2017

An epigenetic breeding system in soybean for increased yield and stability

Epigenetic variation has been associated with a wide range of adaptive phenotypes in plants, but there exist few direct means for exploiting this variation. RNAi suppression of the plant-specific gene, MutS HOMOLOG1 (MSH1), in multiple plant species produces a range of developmental changes accompanied by modulation of defense, phytohormone, and abiotic stress response pathways. This msh1-conditioned developmental reprogramming is retained independent of transgene segregation, giving rise to transgene-null memory effects. An isogenic memory line crossed to wild type produces progeny families displaying increased variation in adaptive traits that respond to selection. This study investigates amenability of the MSH1 system for inducing epigenetic variation in soybean that may be of value agronomically. We developed epi-line populations by crossing with msh1-acquired soybean memory lines. Derived soybean epi-lines showed increase in variance for multiple yield-related traits including pods per plant, seed weight, and maturity time in both greenhouse and field trials. Selected epi-F2:4 and epi-F2:5 lines showed an increase in seed yield over wild type. By epi-F2:6, we observed a return of MSH1-derived enhanced growth back to wild type levels. Epi-populations also showed evidence of reduced epitype-by-environment (e x E) interaction, indicating higher yield stability. Transcript profiling of the soybean epi-lines identified putative signatures of enhanced growth behavior across generations. Genes related to cell cycle, abscisic acid biosynthesis, and auxin-response, particularly SMALL AUXIN UP RNAs (SAURs), were differentially expressed in epi-F2:4 lines that showed increased yield when compared to epi-F2:6. These data support the potential of msh1-derived epigenetic variation in plant breeding for enhanced yield and yield stability.

plant biology↗