Publications by authors named "Saumya Das"

Article Synopsis
  • Recent advancements in extracellular vesicle (EV) biology are recognized for their potential impact on health and disease, particularly in vision research.
  • The National Eye Institute (NEI) highlighted EV research in its 2021-2025 Strategic Plan as a key focus area within Regenerative Medicine.
  • A workshop was held with twenty experts to assess the state of EV research and identify opportunities for its application in diagnosing and treating eye diseases.
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Hepatic steatosis is a central phenotype in multi-system metabolic dysfunction and is increasing in parallel with the obesity pandemic. We use a translational approach integrating clinical phenotyping and outcomes, circulating proteomics, and tissue transcriptomics to identify dynamic, functional biomarkers of hepatic steatosis. Using multi-modality imaging and broad proteomic profiling, we identify proteins implicated in the progression of hepatic steatosis that are largely encoded by genes enriched at the transcriptional level in the human liver.

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We characterized circulating extracellular vesicles (EVs) in obese and lean humans, identifying transcriptional cargo differentially expressed in obesity. Since circulating EVs may have broad origin, we compared this obesity EV transcriptome to expression from human visceral adipose tissue derived EVs from freshly collected and cultured biopsies from the same obese individuals. Using a comprehensive set of adipose-specific epigenomic and chromatin conformation assays, we found that the differentially expressed transcripts from the EVs were those regulated in adipose by BMI-associated SNPs from a large-scale GWAS.

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Article Synopsis
  • Exosomes are small membrane-bound vesicles playing key roles in various biological processes, and an innovative transgenic mouse model called Exomap1 was developed to study their biology.
  • The Exomap1 mouse expresses a fluorescent exosome marker (HsCD81mNG) specifically when induced by Cre recombinase, allowing for tracking and analysis of exosome secretion and composition.
  • Findings showed distinct contributions from different cell types to exosome populations, with neurons contributing ~1% and hepatocytes ~15% to plasma exosomes, affirming the model's utility for exosome research.
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Given expanding studies in epidemiology and disease-oriented human studies offering hundreds of associations between the human "ome" and disease, prioritizing molecules relevant to disease mechanisms among this growing breadth is important. Here, we link the circulating proteome to human heart failure (HF) propensity (via echocardiographic phenotyping and clinical outcomes) across the lifespan, demonstrating key pathways of fibrosis, inflammation, metabolism, and hypertrophy. We observe a broad array of genes encoding proteins linked to HF phenotypes and outcomes in clinical populations dynamically expressed at a transcriptional level in human myocardium during HF and cardiac recovery (several in a cell-specific fashion).

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High-sensitivity flow cytometers have been developed for multi-parameter characterization of single extracellular vesicles (EVs), but performance varies among instruments and calibration methods. Here we compare the characterization of identical (split) EV samples derived from human colorectal cancer (DiFi) cells by three high-sensitivity flow cytometers, two commercial instruments, CytoFLEX/CellStream, and a custom single-molecule flow cytometer (SMFC). DiFi EVs were stained with the membrane dye di-8-ANEPPS and with PE-conjugated anti-EGFR or anti-tetraspanin (CD9/CD63/CD81) antibodies for estimation of EV size and surface protein copy numbers.

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Objective: The objective of this study was to identify the transcriptional landscape of insulin resistance (IR) in subcutaneous adipose tissue (SAT) in humans across the spectrum of obesity.

Methods: We used SAT RNA sequencing in 220 individuals with metabolic phenotyping.

Results: We identified a 35-gene signature with high predictive accuracy for homeostatic model of IR that was expressed across a variety of non-immune cell populations.

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Mild Cognitive Impairment (MCI) is swiftly emerging as a prevalent clinical concern within the elderly demographic. Willoughby spearheaded the pioneering investigation into the evolution of memory decline spanning from the age of 20 to 70. Employing a computerized substitution examination, he pinpointed a zenith in memory prowess at the age of 22, signifying the shift from infancy, succeeded by a gradual decline in later years in 1929.

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Antibodies are critical tools for research into extracellular vesicles (EVs) and other extracellular nanoparticles (ENPs), where they can be used for their identification, characterization, and isolation. However, the lack of a centralized antibody platform where researchers can share validation results thus minimizing wasted personnel time and reagents, has been a significant obstacle. Moreover, because the performance of antibodies varies among assay types and conditions, detailed information on assay variables and protocols is also of value.

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Article Synopsis
  • - The study investigates over 2,000 young adults to identify metabolic factors that contribute to weight gain during early adulthood, rather than relying solely on BMI "snapshots."
  • - A unique metabolic signature was found, correlating with an average BMI increase of 2.6% over approximately 20 years for each standard deviation increase in the score, highlighting significant metabolic influences on weight gain.
  • - The research emphasizes the intricate nature of metabolic regulation in weight gain and advises caution when using traditional epidemiological or genetic measures in metabolic studies.
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Metabolic dysfunction-associated steatotic liver disease (MASLD) prevalence is increasing in parallel with an obesity pandemic, calling for novel strategies for prevention and treatment. We defined a circulating proteome of human MASLD across ≈7000 proteins in ≈5000 individuals from diverse, at-risk populations across the metabolic health spectrum, demonstrating reproducible diagnostic performance and specifying both known and novel metabolic pathways relevant to MASLD (central carbon and amino acid metabolism, hepatocyte regeneration, inflammation, fibrosis, insulin sensitivity). A parsimonious proteomic signature of MASLD was associated with a protection from MASLD and its related multi-system metabolic consequences in >26000 free-living individuals, with an additive effect to polygenic risk.

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  • - Mitral valve prolapse (MVP) is a common degenerative heart disease affecting 2-3% of adults, with 5-10% of cases progressing to serious complications like heart failure and sudden death.
  • - Similar to humans, affected dogs show changes in valvular interstitial cells (VICs) that resemble activated myofibroblasts, characterized by increased alpha-smooth muscle actin (αSMA) expression.
  • - Research on VICs and their small extracellular vesicles (sEV) revealed that certain non-coding RNAs are upregulated in MVP, and targeting the interaction between miRNA and KLF4 could serve as a potential therapy for managing MVP abnormalities. *
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  • - The study investigates the relationship between plasma microRNAs (miRNAs) and key cardiac biomarkers like NT-proBNP and troponin in patients with heart failure, measuring their impact on heart structure and function.
  • - Utilizing data from 139 heart failure patients, researchers found significant associations between specific miRNAs and clinical heart metrics, revealing how these factors predict heart function and future health events.
  • - The findings suggest that analyzing miRNAs alongside traditional biomarkers offers better prognostic insights for heart failure patients, indicating their potential role in assessing cardiovascular health outcomes.
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Extracellular vesicles (EVs) are membrane-bound nanoparticles with different types of cargo released by cells and postulated to mediate functions such as intercellular communications. Recent studies have shown that long non-coding RNAs (lncRNAs) or their fragments are present as cargo within EVs. LncRNAs are a heterogeneous group of RNA species with a length exceeding 200 nucleotides with diverse functions in cells based on their localization.

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BACKGROUNDCardiorenal syndrome (CRS) - renal injury during heart failure (HF) - is linked to high morbidity. Whether circulating extracellular vesicles (EVs) and their RNA cargo directly impact its pathogenesis remains unclear.METHODSWe investigated the role of circulating EVs from patients with CRS on renal epithelial/endothelial cells using a microfluidic kidney-on-chip (KOC) model.

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Atrial fibrillation (AF) is the most common arrhythmia worldwide and is associated with increased morbidity and mortality. The mechanisms underlying AF are complex and multifactorial. Although it is well known that obesity is a strong risk factor for AF, the mechanisms underlying obesity-related AF are not completely understood.

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Extracellular vesicles (EVs) and their cargo constitute novel biomarkers. EV subpopulations have been defined not only by abundant tetraspanins (e.g.

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Exosomes are small extracellular vesicles (sEVs) of ~30-150 nm in diameter that have the same topology as the cell, are enriched in selected exosome cargo proteins, and play important roles in health and disease. To address large unanswered questions regarding exosome biology , we created the transgenic mouse model. In response to Cre recombinase, mice express HsCD81mNG, a fusion protein between human CD81, the most highly enriched exosome protein yet described, and the bright green fluorescent protein mNeonGreen.

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