Biology subjects

Irudayaraj, J.

Publications and source records attributed to Irudayaraj, J..

8 recordsLinked to original sources

bioRxiv2026

TUMOR HETEROGENEITY AND STEMNESS CAN BE SHAPED BY MECHANO-STRUCTURAL PARAMETERS IN OSTEOSARCOMA

Chemoresistance and recurrence of osteosarcoma (OS) can be attributed to a subpopulation of OS cells known as OS Cancer Stem-like Cells (OS-CSCs). We hypothesized that certain mechano-structurally distinct niches within the bone and tumor might be more conducive to OS-CSC formation. Using biomaterial-based 3D scaffolds of distinct structural and mechanical properties (anisotropic soft [~]10 kPa vs isotropic stiff [~]35 kPa), we discovered that OS cells growing in softer, anisotropic scaffolds were rounder, softer, had higher stemness gene expression, showed increased chemoresistance to doxorubicin and cisplatin, and were more tumorigenic in vivo. Mechanistically, biological reprogramming of OS cells on these scaffolds occurred through niche-driven transcriptional changes and differences in chemoresistance-associated epigenetic pathways. Our study showed that a softer, anisotropic niche is more conducive for maintaining OS-CSCs and these findings could be translated to designing therapeutic strategies targeting heterogeneous tumor populations or modifying the microarchitecture to reduce CSC-favoring niches.

cancer biology↗

bioRxiv2026

The Urinary Tract Commensal Peptoniphilus spp. Encodes a Novel 17β-Hydroxysteroid Dehydrogenase

Microbial steroid metabolism represents an underappreciated extension of the vertebrate endocrine system, with growing evidence that host-associated microbes contribute to the diversity and bioavailability of sex steroids within human tissues. Emerging studies have linked microbial androgen metabolism to urinary microbiome composition and to resistance to androgen deprivation therapy (ADT) in prostate cancer. While microbial pathways capable of converting steroid precursors such as cortisol to androgens, via the steroid-17,20-desmolase pathway, such as DesG-mediated interconversion of androstenedione to testosterone have been reported, the diversity of enzymes mediating downstream androgen interconversion remains incompletely defined. Here, we investigate the androgen-forming capabilities of anaerobic bacteria from the male genitourinary microbiome, focusing on NADPH-dependent 17{beta}-hydroxysteroid dehydrogenases (17{beta}-HSDHs) that catalyze interconversion of androstenedione and testosterone. We isolated androgen-forming bacterial strains from human male urine and identified a previously uncharacterized 17{beta}-HSDH encoded by Peptoniphilus obesi, demonstrated that this enzyme catalyzes the NADPH-dependent reduction of androstenedione to testosterone and the reverse oxidation reaction. Sequence similarity searches further identified a homologous 17{beta}-HSDH in Anaerococcus, which was synthesized and functionally validated, revealing conserved activity despite low sequence identity to the previously characterized urinary tract enzyme DesG. The enzymes were found to have broad substrate specificity for C19 and C18 17keto- and 17{beta}-hydroxysteroids. Together, these findings expand the known diversity of microbial 17{beta}-HSDHs and identify previously unrecognized androgen-forming activities within the genitourinary microbiome. ImportanceMicrobial steroid-transforming pathways may provide a mechanism by which commensal anaerobes contribute to androgen availability in the genitourinary tract. By identifying novel 17{beta}-hydroxysteroid dehydrogenases from Peptoniphilus and Anaerococcus, genera repeatedly associated with prostate cancer, this study provides mechanistic insight into how microbial steroid metabolism may influence hormone-driven disease.

microbiology↗

bioRxiv2025

The urinary pathobiont Actinobaculum massiliense generates androgens via the dirAB pathway

While overlooked during the Human Microbiome Project, characterizing the urinary microbiota in health and disease is a new frontier in microbiome science. Recent studies have associated differential abundance of bacterial taxa including Propionimicrobium lymphophilum and Actinobaculum/Actinotignum spp. with prostate cancer. In this study, we collected urine from subjects prior to prostate biopsy and applied a novel Human Sterolbiome Discovery High-throughput (HSDH) assay to identify culturable urinary bacteria with the ability to generate androgens. Application of the HSDH assay to urine samples led to the isolation of eight P. lymphophilum strains positive for cortisol side-chain cleavage (steroid-17,20-desmolase), 17{beta}-HSDH activity, or both. In addition, we isolated three strains of Actinobaculum massiliense that encode DHEA isomerase reductase (dir) genes. The dirA gene encodes a novel 3{beta}/17{beta}-hydroxysteroid dehydrogenase/{Delta}4,5-isomerase and the dirB gene encodes a novel 17{beta}-hydroxysteroid dehydrogenase isoform. Structural prediction and molecular dynamics reveal probable catalytic mechanisms based on the shared catalytic triad but distinct binding pocket geometries of the DirA and DirB that describe their respective reactions. Phylogenetic analysis of DirA and DirB revealed homologs in urinary tract commensals as well as bacteria associated with steroid degradation found in aquatic and terrestrial environments. Taken together, the development of the HSDH assay and the identification of the dir pathway genes is a significant advance in microbial endocrinology, laying the methodological foundation and providing the molecular basis for understanding the role of urinary tract bacteria in host endocrine physiology.

microbiology↗

bioRxiv2024

An expanded metabolic pathway for androgen production by host-associated bacteria

A growing body of literature implicates host-associated microbiota in the modulation of circulating androgen levels in the host, which could have far-reaching implications for androgen-mediated diseases. However, the microbial genetic pathways involved in androgen production remain unknown. Here, we report the first host-associated microbial gene (desF) encoding an enzyme that catalyzes conversion of androstenedione to epitestosterone (epiT) in the gut bacterium, Clostridium scindens. Despite current dogma that epiT is a nuclear androgen-receptor (AR) antagonist, we demonstrate that epiT is a potent androgen, as assessed by its ability to promote prostate cancer cell growth and expression of prostate specific antigen (PSA). We then quantified the desF gene in fecal samples collected from individuals with advanced prostate cancer (rising blood PSA) undergoing androgen deprivation therapy combined with abiraterone acetate and prednisone (AA/P). Strikingly, fecal desF levels were elevated in a subset of individuals progressing on AA/P versus samples taken during AA/P response (stable). Importantly, we observed that AA does not inhibit the bacterial desmolase enzyme that is analogous to the human drug target of AA. We then determined that bacterial isolates from urine or prostatectomy tissue are capable of androgen production. From these isolates we detected 17{beta}-hydroxysteroid dehydrogenase (17{beta}-HSDH) activity, which has not been previously reported in urinary tract bacteria, and discovered the desG gene in urinary isolates encoding 17{beta}-HSDH that catalyzed conversion of androstenedione to testosterone. Applying advanced artificial intelligence and molecular dynamics, we predict the structures and ligand binding to DesF and DesG. Using a novel bioengineered microencapsulation technique, we demonstrate that urinary androgen-producing bacterial strains can also promote prostate cancer cell growth through steroid metabolism. Taken together, our results are a significant advance for steroid microbiology in humans and suggest that these microbial biotransformations should be further studied in the context of androgen-mediated physiological processes and diseases.

microbiology↗

bioRxiv2024

MicroRNAs and PFAS: A Pilot Study in Blood Collected from Firefighters

Per- and polyfluoroalkyl substances (PFAS) are chemicals with widespread industrial and consumer applications, and firefighters are known to be at risk of elevated PFAS exposure due to their occupational activities. This study aims to assess PFAS exposure and explore potential mechanistic insights through miRNA sequencing of plasma exosomes, in relation to PFAS levels in the general population. The study included 34 firefighter participants. PFAS levels in plasma were analyzed, and miRNA sequencing of plasma exosomes was conducted. The findings were compared with the general population data from the National Health and Nutrition Examination Survey (NHANES). While total PFAS levels did not significantly differ between firefighters and the general population in the cohort considered, variations in individual PFAS compounds were observed. MiRNA sequencing revealed substantial heterogeneity in miRNA expression patterns. Associations between serum PFAS levels and biochemical indicators suggested potential health implications, although further mechanistic insights need to be explored.

pharmacology and toxicology↗

bioRxiv2024

Kidney toxicology of a novel compound Lithium Bis(trifluoromethanesulfonyl)imide (LiTFSI, ie. HQ-115) used in energy applications: an Epigenetic evaluation

Exposure to emerging energy-based environmental contaminants such as lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), more commonly known as HQ-115, poses a significant threat to human health, yet its impact on kidney function and epigenetic regulation remains poorly understood. Here, we investigated the effects of LiTFSI exposure on kidney-related biochemical parameters, renal injuries, and epigenetic alterations in male CD-1 mice under both 14-day and 30-day exposure durations. Our study revealed that LiTFSI exposure led to changes in kidney-related biochemical indicators, notably affecting serum bicarbonate levels, while relative kidney weight remained unaffected. Histological analysis unveiled tubule dilation, inflammation, and loss of kidney structure in LiTFSI-exposed mice, alongside dysregulated expression of genes associated with inflammation, renal function, and uric acid metabolism. Epigenetic analysis further identified widespread DNA methylation changes in the two exposure regimes. Functional analysis revealed that differentially methylated regions are implicated in cell apoptosis and cancer-related pathways and are enriched with development-related transcription factor binding motifs, suggesting a potential mechanism of action that can lead to kidney injury. These findings underscore the intricate interplay between environmental exposures, epigenetic modulation, and kidney health, emphasizing the need for additional research to unravel precise mechanisms that can help in the development of targeted interventions to mitigate the adverse effects of LiTFSI exposure on human health. SYNOPSISLiTFSI (HQ-115), an emerging environmental contaminant, impacts kidney health in male CD-1 mice by altering biochemical indicators, to result in renal injuries, and inducing epigenetic changes, highlighting environmental health concerns.

pharmacology and toxicology↗

bioRxiv2023

PFAS assessment in fish: samples from Illinois waters

Per- and Polyfluoroalkyl substances (PFAS) have been widely used in various industries, including pesticide production, electroplating, packaging, paper making, and the manufacturing of water-resistant clothes. This study investigates the levels of PFAS in fish tissues collected from four target waterways (15 sampling points) in the northwestern part of Illinois during 2021-2022. To assess accumulation, concentrations of 17 PFAS compounds were evaluated in nine fish species to potentially inform on exposure risks to local sport fishing population via fish consumption. At least four PFAS (PFHxA, PFHxS, PFOS, and PFBS) were detected at each sampling site. The highest concentrations of PFAS were consistently found in samples from the Rock River, particularly in areas near urban and industrial activities. PFHxA emerged as the most accumulated PFAS in the year 2022, while PFBS and PFOS dominated in 2021. Channel Catfish exhibited the highest PFAS content across different fish species, indicating its bioaccumulation potential across the food chain. Elevated levels of PFOS were observed in nearly all fish, indicating the need for careful consideration of fish consumption. Additional bioaccumulation data in the future years is needed to shed light on the sources and PFAS accumulation potential in aquatic wildlife in relation to exposures for potential health risk assessment.

pharmacology and toxicology↗

bioRxiv2023

In vitro toxicity of LiTFSI on Human Renal and Hepatoma Cells

We evaluate the cytotoxicity, intracellular redox conditions, apoptosis, and methylation of DNMTs/TETs upon exposure to LiTFSI, a novel PFAS compound commonly found in lithium-ion batteries, on human renal carcinoma cells (A498) and hepatoma cells (HepG2). The MTT assay showed both PFOS and LiTFSI had a dose-dependent effect on A498 and HepG2, with LiTFSI being less toxic. Intracellular redox conditions were assessed with a microplate reader and confocal, which showed a significant decrease in ROS levels and an increase in SOD content in both cells. Exposure to LiTFSI enhanced cell apoptosis, with HepG2 being more susceptible than A498. Quantitative analysis of mRNA expression levels of 19 genes associated with kidney injury, methylation, lipid metabolism and transportation was performed. LiTFSI exposure impacted kidney function by downregulating Acta2 and upregulating Tgfb1, Bcl2l1, Harvcr1, Nfe2l2, and Hes1 expression. LiTFSI exposure also affected the abundance of transcripts associated with DNA methylation by the expression of TET and DNMT genes. Furthermore, LiTFSI exposure induced an increase in lipid anabolism and alterations in lipid catabolism in HepG2. Our results provide new insight on the potential role of a new contaminant, LiTFSI in the regulation of oxidative stress, apoptosis and methylation in human renal carcinoma and hepatoma cells.

pharmacology and toxicology↗