Biology subjects

Corvera, S.

Publications and source records attributed to Corvera, S..

12 recordsLinked to original sources

bioRxiv2026

Single-Nuclear RNA Sequencing Reveals Regional Specialization and Cellular Interactions in Epicardial and Perivascular Adipose Tissue

Background: Adipose tissue surrounding the heart and vasculature plays critical roles in cardiovascular homeostasis and disease, yet the cellular and molecular milieu of these depots at single-cell resolution remains incompletely characterized. Understanding how regional adipocytes differ transcriptionally and communicate with neighboring cardiovascular cells is essential for developing targeted therapeutic strategies. Methods: We performed single-nucleus RNA sequencing (snRNA-seq) on human adipose tissue from four anatomically distinct depots: ascending aorta, left atrium, right coronary artery, and subcutaneous fat. We characterized cellular composition, adipocyte and progenitor heterogeneity, depot-specific transcriptional programs, and intercellular communication networks. We further examined signaling remodeling in disease contexts, including atrial fibrillation and aortic aneurysm. Results: We identified six transcriptionally distinct adipocyte subpopulations and six adipocyte stromal and progenitor cell (ASPC) subpopulations were shared across depots but showed marked differences in abundance and gene expression reflecting developmental imprinting, including HOX family genes and anterior-posterior patterning programs. Intercellular communication analysis revealed depot-specific ligand-receptor interactions, with EPHA signaling identified as selectively enriched in the left atrial adipose depot. Disease-state analyses demonstrated extensive change in cell-cell communication in atrial fibrillation and aortic aneurysm, with differential regulation of FN1, EGF, SLIT, NOTCH, and CD46 signaling pathways. Conclusions: Our study reveals that cardiac and vascular adipose depots harbor transcriptionally specialized adipocytes and progenitors with distinct intercellular communication programs that are remodeled in atrial fibrillation and aortic aneurysm.

physiology↗

bioRxiv2025

Seipin mediates Perilipin-1 recruitment to lipid droplets to preserve human adipocyte identity

Congenital generalized lipodystrophy type 2 (CGL2) is caused by mutations in the BSCL2 gene, which encodes the protein seipin. However, how seipin loss causes adipose tissue failure remains unclear. Using human adipocyte progenitor cells capable of robust differentiation in vitro and in vivo, we reveal two unexpected findings that redefine CGL2 pathogenesis. First, seipin is dispensable for lipid droplet biogenesis but essential for recruiting the major adipocyte scaffold protein Perilipin 1 (PLIN1) to the lipid droplet surface. Second, we discover that the integrity of the lipid droplet serves as an organelle to nucleus quality control checkpoint enforcing adipocyte identity. Without seipin-dependent PLIN1 recruitment, adipocytes exhibit enhanced lipolysis and ceramide accumulation, triggering an unexpected cellular response of de-differentiation into a progenitor-like state. From this de-differentiated state, cells can undergo additional cycles of differentiation and de-differentiation upon repeated adipogenic stimuli. However, some cells escape de-differentiation, instead forming a single large droplet and displaying severe cellular structural abnormalities. Consistent with this model, we find functional adipose tissue can form in vivo from seipin-deficient cells, yet ultimately fails. These findings resolve conflicting models of CGL2 pathogenesis by reframing seipin as a regulator of PLIN1 recruitment, rather than droplet formation per se, and reveal the fundamental role of lipid droplet integrity in the development of functional human adipocytes.

cell biology↗

bioRxiv2025

Thermogenic adipocytes alleviate hepatic steatosis and insulin resistance via macrophage cytokine secretion in obese mice

The Nrip1 gene encodes the protein Rip140, which suppresses nuclear receptors that regulate energy metabolism. Here we show adipocyte-selective deficiency of Nrip1 (AdNrip1KO) in mice causes a striking expansion of alternatively activated, M2-like macrophages within subcutaneous inguinal adipose tissue (iWAT) in addition to the appearance of thermogenic adipocytes expressing uncoupling protein 1 (UCP1). AdNrip1KO mice are less cold sensitive but showed no differences in whole body energy expenditure or food intake compared to control mice at 22 {degrees}C. Strikingly, AdNrip1KO mice on HFD display markedly attenuated hepatic steatosis and insulin resistance compared to control mice on HFD. Secreted factors that might mediate this crosstalk from adipose tissue to liver were searched for by iWAT RNAseq. Unexpectedly, upregulation of genes associated with cytokines and cytokine receptor signaling were the most highly correlated with adipocyte-selective Nrip1 loss in obese mice. Furthermore, the top upregulated genes that encode secreted proteins in AdNrip1KO iWAT are most highly expressed in macrophages, not adipocytes. This list included the IL-1b antagonist IL-1rn, known to attenuate hepatic steatosis and insulin resistance. Indeed, the IL-1rn protein in AdNrip1KO mice was found to circulate at levels we previously reported strongly attenuates hepatic steatosis and glucose tolerance in obese mice. Taken together, these results suggest a paradigm for metabolic crosstalk from thermogenic adipose tissue to liver that is mediated by IL-1rn and potentially other factors secreted from M2-like macrophages within beige adipose tissues. Graphic Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=123 SRC="FIGDIR/small/667482v1_ufig1.gif" ALT="Figure 1"> View larger version (31K): org.highwire.dtl.DTLVardef@15fb086org.highwire.dtl.DTLVardef@13e6689org.highwire.dtl.DTLVardef@1bde77borg.highwire.dtl.DTLVardef@a83f2e_HPS_FORMAT_FIGEXP M_FIG C_FIG HighlightsO_LIAdipocyte Nrip1 deficiency (AdNrip1KO) strongly promotes adipose browning C_LIO_LIMouse AdNrip1KO polarizes adipose tissue macrophages towards M2-like C_LIO_LIAdNrip1KO reduces the hepatic fat and insulin resistance of obese mice C_LIO_LIAdNrip1KO adipose tissue macrophages secrete IL-1rn, known to mitigate hepatic fat and insulin resistance C_LI

physiology↗

bioRxiv2024

PPARγ activation by lipolysis-generated ligands is required for cAMP dependent UCP1 induction in human thermogenic adipocytes

ObjectiveThe uncoupling protein 1 (UCP1) is induced in brown or "beige" adipocytes through catecholamine-induced cAMP signaling, which activates diverse transcription factors. UCP1 expression can also be enhanced by PPAR{gamma} agonists such as rosiglitazone (Rsg). However, it is unclear whether this upregulation results from de-novo differentiation of beige adipocytes from progenitor cells, or from the induction of UCP1 in pre-existing adipocytes. To explore this, we employed human adipocytes differentiated from progenitor cells and examined their acute response to Rsg, to the adenylate-cyclase activator forskolin (Fsk), or to both simultaneously. MethodsAdipocytes generated from primary human progenitor cells were differentiated without exposure to PPAR{gamma} agonists, and treated for 3, 6 or 78 hours to Fsk, to Rsg, or to both simultaneously. Bulk RNASeq, RNAScope, RT-PCR, CRISPR-Cas9 mediated knockout, oxygen consumption and western blotting were used to assess cellular responses. ResultsUCP1 mRNA expression was induced within 3 hours of exposure to either Rsg or Fsk, indicating that Rsgs effect is independent on additional adipocyte differentiation. Although Rsg and Fsk induced distinct overall transcriptional responses, both induced genes associated with calcium metabolism, lipid droplet assembly, and mitochondrial remodeling, denoting core features of human adipocyte beiging. Unexpectedly, we found that Fsk-induced UCP1 expression was reduced by approximately 80% following CRISPR-Cas9-mediated knockout of PNPLA2, the gene encoding the triglyceride lipase ATGL. As anticipated, ATGL knockout suppressed lipolysis; however, the associated suppression of UCP1 induction indicates that maximal cAMP-mediated UCP1 induction requires products of ATGL-catalyzed lipolysis. Supporting this, we observed that the reduction in Fsk-stimulated UCP1 induction caused by ATGL knockout was reversed by Rsg, implying that the role of lipolysis in this process is to generate natural PPAR{gamma} agonists. ConclusionUCP1 transcription is known to be stimulated by transcription factors activated downstream of cAMP-dependent protein kinases. Here we demonstrate that UCP1 transcription can also be acutely induced through PPAR{gamma}-activation. Moreover, both pathways are activated in human adipocytes in response to cAMP, synergistically inducing UCP1 expression. The stimulation of PPAR{gamma} in response to cAMP occurs as a result of the production of natural PPAR{gamma} activating ligands through ATGL-mediated lipolysis. GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=161 SRC="FIGDIR/small/607465v1_ufig1.gif" ALT="Figure 1"> View larger version (29K): org.highwire.dtl.DTLVardef@18675a5org.highwire.dtl.DTLVardef@95cb66org.highwire.dtl.DTLVardef@5cb189org.highwire.dtl.DTLVardef@18bac05_HPS_FORMAT_FIGEXP M_FIG C_FIG

cell biology↗

bioRxiv2023

A distinct class of hematopoietic stem cells develop from the human yellow bone marrow

During aging, adipose tissue within the bone marrow expands while the trabecular red marrow contracts. The impact of these changes on blood cell formation remains unclear. To address this question, we performed single-cell and single-nuclei transcriptomic analysis on adipose-rich yellow bone marrow (BMY) and adipose-poor trabecular red marrow (BMR) from human subjects undergoing lower limb amputations. Surprisingly, we discovered two distinct hematopoietic niches, in which BMY contains a higher number of monocytes and progenitor cells expressing genes associated with inflammation. To further investigate these niches, we developed an in-vitro organoid system that maintains features of the human bone marrow. We find cells from BMY are distinct in their expression of the leptin receptor, and respond to leptin stimulation with enhanced proliferation, leading to increased monocyte production. These findings suggest that the age-associated expansion of bone marrow adipose tissue drives a pro-inflammatory state by stimulating monocyte production from a spatially distinct, leptin-responsive hematopoietic stem/progenitor cell population. SignificanceThis study reveals that adipose tissue within the human bone marrow is a niche for hematopoietic stem and progenitor cells that can give rise to pro-inflammatory monocytes through leptin signaling. Expansion of bone marrow adipose tissue with age and stress may thus underlie inflammageing.

developmental biology↗

bioRxiv2023

Regulation of lipolysis by 14-3-3 proteins on human adipocyte lipid droplets.

Adipocyte lipid droplets (LDs) play a crucial role in systemic lipid metabolism by storing and releasing lipids to meet the organisms energy needs. Hormonal signals such as catecholamines and insulin act on adipocyte LDs, and impaired responsiveness to these signals can lead to uncontrolled lipolysis, lipotoxicity, and a higher risk of metabolic diseases. To investigate the mechanisms that control LD function in human adipocytes, we employed techniques to obtain mesenchymal progenitor cells on a large scale and applied proximity labeling mediated by enhanced ascorbate peroxidase (APEX2) to identify the interactome of PLIN1 in differentiated adipocytes. We identified 70 proteins that interact specifically with PLIN1, including PNPLA2 and LIPE, which are the primary effectors of regulated triglyceride hydrolysis, and four members of the 14-3-3 protein family (YWHAB, YWHAE, YWHAZ, and YWHAG), which are known to regulate diverse signaling pathways. Functional studies showed that YWHAB is required for maximum cAMP-stimulated lipolysis and helps to mitigate the anti-lipolytic effects of insulin. These findings reveal new regulatory mechanisms that control lipolysis in human metabolism. SIGNIFICANCE STATEMENTLipid droplets are ubiquitous cytoplasmic organelles that store metabolic energy and play a key role in cellular lipid metabolism (1). Adipocyte LDs play an additional, crucial role, as they supply the energy needs of the whole body through hormonally regulated triglyceride synthesis, storage, and release. The mechanisms by which adipocyte lipid droplets release lipids for systemic use has been mostly studied in mouse models and cell lines. To understand how lipid mobilization is controlled in human adipocytes, we used proximity labeling to identify proteins that interact with PLIN1, a major component of the lipid droplet, in adipocytes generated from primary human progenitor cells. Our study catalogues the interactome of human PLIN1 and identifies previously unrecognized potential mechanism for control of human adipocyte lipolysis through 14-3-3 proteins.

cell biology↗

bioRxiv2022

Canonical Wnt Signaling Maintains Human Mesenchymal Progenitor Cell Multipotency During Adipose Tissue Development

Tissue development and repair throughout life depends on the availability of multipotent mesenchymal stem/progenitor cells capable of differentiating into specialized cell types. How an appropriately sized pool of such multipotent progenitors is maintained under varied signals for tissue growth and repair is unknown. We addressed this question by monitoring fate trajectories of human adipose tissue-derived multipotent progenitor cells using single-cell transcriptomics. Homogenous multipotent progenitors underwent two distinct fate trajectories rapidly upon induction of adipose differentiation- one toward the adipocyte fate, and the other towards a distinct, non-differentiated state characterized by up-regulation of canonical Wnt target genes. Upon isolation, this latter cell population was able to resume proliferation and display multipotency. Using canonical Wnt agonists and antagonists we find Wnt signaling is required for the maintenance of this multipotent pool under differentiation stimulus. In vivo, these cells are retained in adipose tissue developed from human multipotent progenitor cells in immunocompromised mice, and their transcriptomic signature is detected in human adult adipose tissue. Our study reveals a previously unrecognized mechanism for maintaining a functional pool of human mesenchymal progenitor cells under conditions of differentiation pressure, driven by Wnt signaling.

developmental biology↗

bioRxiv2021

A NEUROGENIC GENE EXPRESSION SIGNATURE SUPPORTS HUMAN THERMOGENIC ADIPOSE TISSUE DEVELOPMENT IN VIVO.

Mechanisms that control "beige/brite" thermogenic adipose tissue development may be harnessed to improve human metabolic health. To define these mechanisms, we developed a species-hybrid model in which human mesenchymal progenitor cells were used to develop white or thermogenic/beige adipose tissue in mice. The hybrid adipose tissue developed distinctive features of human adipose tissue, such as larger adipocyte size, despite its neurovascular architecture being entirely of murine origin. Thermogenic adipose tissue recruited a denser, qualitatively distinct vascular network, differing in genes mapping to circadian rhythm pathways, and denser sympathetic innervation. The enhanced thermogenic neurovascular network was associated with human adipocyte expression of THBS4, TNC, NTRK3 and SPARCL1, which enhance neurogenesis, and decreased expression of MAOA and ACHE, which control neurotransmitter tone. Systemic inhibition of MAOA, which is present in human but absent in mouse adipocytes, induced browning of human but not mouse adipose tissue, revealing the physiological relevance of this pathway. Our results reveal species-specific cell type dependencies controlling the development of thermogenic adipose tissue and point to human adipocyte MAOA as a potential target for metabolic disease therapy.

developmental biology↗

bioRxiv2020

CRISPR-enhanced human adipocyte 'browning' as cell therapy for metabolic disease

Obesity and type 2 diabetes (T2D) are associated with poor tissue responses to insulin1,2, disturbances in glucose and lipid fluxes3-5 and comorbidities including steatohepatitis6 and cardiovascular disease7,8. Despite extensive efforts at prevention and treatment9,10, diabetes afflicts over 400 million people worldwide11. Whole body metabolism is regulated by adipose tissue depots12-14, which include both lipid-storing white adipocytes and less abundant "brown" and "brite/beige" adipocytes that express thermogenic uncoupling protein UCP1 and secrete factors favorable to metabolic health15-18. Application of clustered regularly interspaced short palindromic repeats (CRISPR) gene editing19,20 to enhance "browning" of white adipose tissue is an attractive therapeutic approach to T2D. However, the problems of cell-selective delivery, immunogenicity of CRISPR reagents and long term stability of the modified adipocytes are formidable. To overcome these issues, we developed methods that deliver complexes of SpyCas9 protein and sgRNA ex vivo to disrupt the thermogenesis suppressor gene NRIP121,22 with near 100% efficiency in human or mouse adipocytes. NRIP1 gene disruption at discrete loci strongly ablated NRIP1 protein and upregulated expression of UCP1 and beneficial secreted factors, while residual Cas9 protein and sgRNA were rapidly degraded. Implantation of the CRISPR-enhanced human or mouse brown-like adipocytes into high fat diet fed mice decreased adiposity and liver triglycerides while enhancing glucose tolerance compared to mice implanted with unmodified adipocytes. These findings advance a therapeutic strategy to improve metabolic homeostasis through CRISPR-based genetic modification of human adipocytes without exposure of the recipient to immunogenic Cas9 or delivery vectors.

bioengineering↗

bioRxiv2019

Multiple human adipocyte subtypes and mechanisms of their development

Human adipose tissue depots perform numerous diverse physiological functions, and are differentially linked to metabolic disease risk, yet only two major human adipocyte subtypes have been described, white and "brown/brite/beige." The diversity and lineages of adipocyte classes have been studied in mice using genetic methods that cannot be applied in humans. Here we circumvent this problem by studying the fate of single mesenchymal progenitor cells obtained from human adipose tissue. We report that a minimum of four human adipocyte subtypes can be distinguished by transcriptomic analysis, specialized for functionally distinct processes such as adipokine secretion and thermogenesis. Evidence for the presence of these adipocytes subtypes in adult humans is evidenced by differential expression of key adipokines leptin and adiponectin in isolated mature adipocytes. The human adipocytes most similar to the mouse "brite/beige" adipocytes are enriched in mechanisms that promote iron accumulation and protect from oxidative stress, and are derived from progenitors that express high levels of cytokines such as IL1B, IL8, IL11 and the IL6 family cytokine LIF, and low levels of the transcriptional repressors ID1 and ID3. Our finding of this adipocyte repertoire and its developmental mechanisms provides a high-resolution framework to analyze human adipose tissue architecture and its role in systemic metabolism and metabolic disease.

physiology↗

bioRxiv2018

A long-non-coding RNA, LINC00473, confers the human adipose tissue thermogenic phenotype through enhanced cAMP responsiveness.

Specialized adipocytes localized in distinct depots mediate the many physiological functions of adipose tissue. In humans, paucity of thermogenic adipocytes correlates with high metabolic disease risk, raising much interest in the mechanisms by which these cells arise. Here we report molecular signatures associated with adipocyte development in different human depots and identify a long non-coding RNA, LINC00473, as the transcript most closely associated with enrichment of thermogenic adipocytes. LINC00473 expression is low in subjects with obesity or type-2 diabetes and is highly correlated with cAMP signaling and mitochondrial oxidative phosphorylation pathways. LINC00473 is localized in the nucleus and the cytoplasm, and its knockdown impairs induction of UCP1 and mitochondrial respiration. These results reveal that depot-enriched genes that modulate responsiveness to external stimuli, specifically LINC00473, are important determinants of the adipose tissue thermogenic phenotype, and potential targets for metabolic disease therapy.

cell biology↗

bioRxiv2018

Generation of functional human adipose tissue in mice from primed progenitor cells

AbstarctAdipose tissue is used extensively in reconstructive and regenerative therapies, but transplanted fat often undergoes inflammation and cell death, requiring further revision surgery. We report that functional human adipose tissue can be generated from mesenchymal progenitor cells in-vivo, providing an alternative approach to its therapeutic use. We leveraged previous findings that progenitor cells within the vasculature of human adipose tissue robustly proliferate in 3-dimensional culture under proangiogenic conditions. Implantation of these progenitor cells into immunocompromised mice results in differentiation towards non-adipocyte fates, incapable of generating a distinct tissue structure. However, priming of these progenitor cells in-vitro towards adipogenic differentiation results in formation of functional adipose tissue in-vivo. Mechanistically, priming induces the expression of genes encoding specific extracellular matrix and remodeling proteins, and induces extensive vascularization by host blood vessels. In comparison, grafts from adipose tissue obtained by liposuction undergo poor vascularization, adipocyte death, cyst formation, calcification and inefficient adiponectin secretion. Thus, primed mesenchymal adipose tissue progenitors reveal mechanisms of human adipose tissue development, and have potential to improve outcomes in reconstructive and regenerative medicine.

bioengineering↗