Biology subjects

Menon, H.

Publications and source records attributed to Menon, H..

6 recordsLinked to original sources

bioRxiv2024

Comparative Analysis of Commercial Single-Cell RNA Sequencing Technologies

This study evaluates ten commercially available single-cell RNA sequencing (scRNA-seq) approaches across four technology groups: Emulsion-based kits from 10x Genomics and Fluent Biosciences; Microwell-based kits from Becton Dickinson, Honeycomb Technologies and Singerlon Technologies; Combinatorial-indexing kits from Parse Biosciences and Scale Biosciences; and a Matrigel-based kit from Scipio Biosciences. Peripheral blood mononuclear cells (PBMCs) from a single donor were used to assess analytical performance. Key features such as sample compatibility, cost, and experimental duration were also compared. Notably, superior analytical performance was demonstrated by the Chromium Fixed RNA Profiling kit from 10x Genomics, which uniquely features probe hybridization for transcript detection. Additionally, the Rhapsody WTA kit from Becton Dickinson provided a cost-effective balance of performance and expense per cell. With a rich dataset of 218,154 cells, this work provides a basis for differentiating commercial scRNA-seq technologies, which is intended to facilitate the effective application and further methodological development of single cell transcriptomics.

molecular biology↗

bioRxiv2024

Post-mortem evidence for a reciprocal relationship between genomic DNA damage and alpha-synuclein pathology in dementia with Lewy bodies.

DNA damage and DNA damage repair (DDR) dysfunction are insults with broad implications on cellular physiology, including in proteostasis, and have been recently implicated in many neurodegenerative diseases. Alpha-synuclein (aSyn), a pre-synaptic and nuclear protein associated with neurodegenerative disorders known as synucleinopathies, has been implicated in DNA double strand break (DSB) repair function. Consistently, DSB induction has been demonstrated in cell and animal models of synucleinopathy. Nevertheless, the types of DNA damage and the contribution of DNA damage towards Lewy body (LB) formation in synucleinopathies are unknown. Here, we demonstrate the increase of DSB in neuronal and non-neuronal cellular populations of post-mortem temporal cortex tissue from dementia with Lewy body (DLB) patients and demonstrate increases in DSBs early at a presymptomatic age of aSyn transgenic mice. Strikingly, in postmortem DLB tissue, DNA damage-derived ectopic cytoplasmic genomic material (eCGM) was evident within the majority of LBs examined. The observed cellular pathology was consistent with nucleoproteasomal upregulation of associated DNA damage repair proteins, particularly in base excision repair and DSB repair pathways. Collectively our study demonstrates the early occurrence of DNA damage and associated nucleoproteasomal changes in response to nuclear aSyn pathology. Furthermore, the data suggests a potential involvement for DNA damage derived eCGM for the facilitation of cytoplasmic aSyn aggregates. Ultimately, uncovering pathological mechanisms underlying DNA damage in DLB sheds light into novel disease mechanisms and opens novel possibilities for diagnosing and treating synucleinopathies.

neuroscience↗

bioRxiv2023

Glomerular immune injury promotes anti-tumor activity

Recent evidence suggests that the interaction between the tumor microenvironment (TME) and systemic host environment can alter the host immune system to promote anti-tumor activity. Here, we investigated whether glomerular immune injury affects cancer progression. We used nephrotoxic serum nephritis (NTN), a model for glomerular immune injury, and followed it by cancer cell implantation. NTS-injected mice developed smaller primary tumors compared with controls. Tumors of NTS-injected mice had more activated CD8 T cells, suggesting a role for the immune system in the anti-tumor phenotype. Using RNA-seq data, we identified transcriptomic alterations in the bone marrow following NTN. Moreover, using scRNA-seq of white blood cells following NTN we found these transcriptomic alterations were reflected in {gamma}{delta} T cells and neutrophils. This is the first study to show that glomerular immune injury changes the transcription of cells in the bone marrow to advance anti-tumor activity. Our study highlights the pivotal role of BM-mediated transcriptional alterations underlying the enhanced host immunity to tumor growth.

cancer biology↗

bioRxiv2023

Aging and senescence-associated analysis of the aged kidney glomerulus highlights the role of mesangial cells in renal aging

Most causes of chronic kidney disease begin with injury to the glomerulus and involve progressive loss of kidney function. The glomerulus is a capillary bed where blood filtration to produce urine in the kidney occurs. During aging, there is progressive loss of glomeruli and filtration capacity of the kidney because podocytes, the glomerular epithelial cell, are lost with aging and after injury. Podocytes cannot divide and therefore cannot be replaced. Our histological analysis confirmed the presence of glomerulosclerosis, generalized interstitial fibrosis and glomerular hypertrophy in the aged mouse kidney. One barrier to studies of glomeruli is their low frequency in the kidney, less than 1.5% of the cells, and as such, they are often underrepresented in whole kidney analyses. To address this challenge, we used both bulk and single cell RNA sequencing (scRNA-Seq) to characterize purified glomeruli from young and aged mice. Aged glomeruli displayed increased inflammation and expressed a variety of injury and senescence-associated markers, most notably in mesangial cells and macrophages. This increased expression of senescence markers in mesangial cells of aged kidneys suggests a potential cellular target to address age-related renal dysfunction and chronic kidney disease (CKD), which represent a tremendous unmet medical need.

cell biology↗

bioRxiv2023

Single-cell long-read targeted sequencing reveals transcriptional variation in ovarian cancer

Single-cell RNA sequencing predominantly employs short-read sequencing to characterize cell types, states and dynamics; however, it is inadequate for comprehensive characterization of RNA isoforms. Long-read sequencing technologies enable single-cell RNA isoform detection but are hampered by lower throughput and unintended sequencing of artifacts. Here we developed Single-cell Targeted Isoform Long-Read Sequencing (scTaILoR-seq), a hybridization capture method which targets over a thousand genes of interest, improving the median number of unique transcripts per cell by 29-fold. We used scTaILoR-seq to identify and quantify RNA isoforms from ovarian cancer cell lines and primary tumors, yielding 10,796 single-cell transcriptomes. Using long-read variant calling we revealed associations of expressed single nucleotide variants (SNVs) with alternative transcript structures. In addition, phasing of SNVs across transcripts facilitated measurement of allelic imbalance within distinct cell populations. Overall, scTaILoR-seq is a long-read targeted RNA sequencing method and analytical framework for exploring transcriptional variation at single-cell resolution.

genomics↗

bioRxiv2023

The renal capsule: a vibrant and adaptive cell environment of the kidney in homeostasis, disease and aging

The kidney is a complex organ that governs many physiological parameters. It is roughly divided into three parts, the renal pelvis, medulla, and cortex. Covering the cortex is the renal capsule, a serosal tissue that provides protection and forms a barrier for the kidney. Serosal tissues of many organs have been recently shown to play a vital role in homeostasis and disease. Analyses of the cells that reside in these tissues have identified distinct cell types with unique phenotypes. Here, we characterized this niche and found that it is mainly comprised of fibroblasts and macrophages, but also includes other diverse cell types. Characterizing renal capsule-associated macrophages, we found that they consist of a distinct subset (i.e., TLF+ macrophages) that is nearly absent in the kidney parenchyma. Injury, disease, and other changes that involve the kidney, affected the cell composition of the renal capsule, indicating its dynamic response to changes within the organ parenchyma. Lastly, we studied age-related changes in the renal capsule and found that aging affected the cell composition and inflammatory phenotype of macrophages, increased CD8 T cells and other lymphocyte counts, and promoted a senescence-associated phenotype in fibroblasts. Taken together, our data illustrate the complexity and heterogeneity of the renal capsule and its underlying changes during aging and disease, improving our understanding of the kidney serosa that may be valuable for novel renal therapies.

immunology↗