Changes in subcutaneous white adipose tissue cellular composition and molecular programs underlie glucose intolerance in persons with HIV

Single-cell immune profiling at time of M. tuberculosis exposure reveals antigen-reactive programs that predict progression to active disease

Early delineation of host immune responses at the moment of Mycobacterium tuberculosis (Mtb) exposure and infection is critical to identify individuals at risk of progressing to active tuberculosis (TB). We performed single-cell transcriptional profiling of over 500,000 peripheral blood mononuclear cells from 57 HIV-negative close contacts of TB cases in Brazil, including 25 individuals who developed active disease within two years (progressors) and 32 matched controls who remained disease-free (non-progressors). Cells were stimulated separately with the MTB300 peptide pool or irradiated Mtb (gRV), enabling resolution of antigen-reactive states across adaptive (CD4⁺ T-cells expressing abundant cytokines including IFNG, TNF, and IL17F) and trained-innate lineages, such as NK cells (producing GM-CSF, IFNG, CCL3, CCL4) and monocytes (GM-CSF, IL12B, IL36G). Progressors exhibited early hyper-metabolic CD4⁺ T-cell programs and proliferative NK cell signatures, whereas non-progressors preferentially upregulated complement activation and CCL3/4-driven chemokine signaling in monocytes. Notably, among progressors, gene expression profiles within antigen-reactive CD4⁺ T-cells and monocytes predicted the timing of progression to active TB. Together, these findings reveal high frequencies and functional diversity of antigen-reactive cells in Mtb-exposed individuals and nominate tractable immune correlates for the rational design of next-generation TB vaccines.

The Primacy of Adipose Tissue Gene Expression and Plasma Lipidome in Cardiometabolic Disease in Persons With HIV

BACKGROUND

Persons with HIV (PWH) on contemporary antiretroviral therapy (ART) are at elevated risk for developing age-related cardiometabolic diseases. We hypothesized that integrative analysis of cross-tissue, multimodal data from PWH could provide insight into molecular programming that defines cardiometabolic phenotypes in this high-risk group.

METHODS

We enrolled 93 PWH without diabetes who were virologically suppressed on contemporary ART and obtained measures of insulin resistance, glucose intolerance, and adiposity. We performed circulating lipidomics, proteomics, and metabolomics, as well as subcutaneous adipose tissue (SAT) bulk transcriptomics, and used multiomics factor analysis (MOFA) to perform integrative analyses of these datasets.

RESULTS

The median age was 43 years, median body mass index 30.8 kg/m2, 81% were male, and 56% were self-identified non-Hispanic White. We identified a specific MOFA factor associated with visceral adipose tissue volume (ρ = -0.43), homeostasis model assessment 2 insulin resistance score (ρ = -0.52), liver density (ρ = 0.43), and other cardiometabolic risk factors, which explained more variance in the SAT transcriptome and circulating lipidome compared with the circulating proteome and metabolome. Gene set enrichment analysis of this factor showed extracellular matrix and inflammatory pathways that primarily mapped to SAT myeloid cells and adipose progenitor cells using single-cell deconvolution. Lipidomic analysis showed that this factor was significantly enriched for triacylglycerol and diacylglycerol species.

CONCLUSIONS

Our multiomic analysis demonstrated coordinated, multitissue molecular reprogramming in virologically suppressed PWH with elevated cardiometabolic disease risk. Longitudinal studies of PWH with assessments of adipose tissue and lipid handling are necessary to understand mechanisms of cardiometabolic disease in PWH. Clinical Trials Registration. NCT04451980.

Single-Cell Analysis of Subcutaneous Fat Reveals Profibrotic Cells That Correlate With Visceral Adiposity in HIV

CONTEXT

Cardiometabolic diseases are common in persons with HIV (PWH) on antiretroviral therapy (ART), which has been attributed to preferential lipid storage in visceral adipose tissue (VAT) compared with subcutaneous adipose tissue (SAT). However, the relationship of SAT-specific cellular and molecular programs with VAT volume is poorly understood in PWH.

OBJECTIVE

We characterized SAT cell-type specific composition and transcriptional programs that are associated with greater VAT volume in PWH on contemporary ART.

METHODS

We enrolled PWH on long-term ART with a spectrum of metabolic health. Ninety-two participants underwent SAT biopsy for bulk RNA sequencing and 43 had single-cell RNA sequencing. Computed tomography quantified VAT volume and insulin resistance was calculated using the Homeostasis Model Assessment 2 Insulin Resistance (HOMA2-IR).

RESULTS

VAT volume was associated with HOMA2-IR (P < .001). Higher proportions of SAT intermediate macrophages (IMs), myofibroblasts, and MYOC+ fibroblasts were associated with greater VAT volume using partial Spearman's correlation adjusting for age, sex, and body mass index (r = 0.34-0.49, P < .05 for all). Whole SAT transcriptomics showed PWH with greater VAT volume have increased expression of extracellular matrix (ECM)- and inflammation-associated genes, and reduced expression of lipolysis- and fatty acid metabolism-associated genes.

CONCLUSION

In PWH, greater VAT volume is associated with a higher proportion of SAT IMs and fibroblasts, and a SAT ECM and inflammatory transcriptome, which is similar to findings in HIV-negative persons with obesity. These data identify SAT cell-type specific changes associated with VAT volume in PWH that could underlie the high rates of cardiometabolic diseases in PWH, though additional longitudinal studies are needed to define directionality and mechanisms.

Cytokine and chemokine receptor profiles in adipose tissue vasculature unravel endothelial cell responses in HIV

Chronic systemic inflammation significantly increases myocardial infarction risk in people living with HIV (PLWH). Endothelial cell dysfunction disrupts vascular homeostasis regulation, increasing the risk of vasoconstriction, inflammation, and thrombosis, contributing to cardiovascular disease. We aimed to characterize endothelial cell (EC) chemokines, cytokine, and chemokine receptors of PLWH, hypothesizing that in our cohort, glucose intolerance contributes to their differential expression implicated in endothelial dysfunction. Using single-cell transcriptomic analysis, we phenotyped chemokine and cytokine receptor expression on arterial ECs, capillary ECs, venous ECs, and vascular smooth muscle cells (VSMCs) in subcutaneous adipose tissue of 59 PLWH with and without glucose intolerance. Our results show that arterial and capillary ECs express significantly higher interferon and tumor necrosis factor (TNF) receptors than venous ECs and VSMCs. Venous ECs exhibited more interleukin (IL)1R1 and ACKR1 receptors, and VSMCs showed significant IL6R expression than arterial and capillary ECs. When stratified by group, arterial ECs from PLWH with glucose intolerance expressed significantly higher IL1R1, IL6R, CXCL12, CCL14, and ICAM2 transcripts than arterial ECs from PLWH without diabetes. Of the different vascular cell types studied, arterial ECs as a proportion of all ECs in adipose tissue were positively correlated with plasma fasting blood glucose. In contrast, venous ECs and VSMCs were positively correlated with plasma IL6. To directly assess the effect of plasma from PLWH on endothelial function, we cultured human arterial ECs (HAECs) in plasma-conditioned media from PLWH and performed bulk RNA sequencing. Plasma from PLWH stimulated ECs with the upregulation of genes that enrich for the oxidative phosphorylation and the TNF-α via NFK-β pathways. In conclusion, ECs in PLWH show heterogeneous cytokine and chemokine receptor expression, and arterial ECs were the most influenced by glucose intolerance. Further research must explicate cytokine and chemokine roles in EC dysfunction and identify biomarkers for disease progression and therapeutic response.

Multiomic single-cell sequencing defines tissue-specific responses in Stevens-Johnson syndrome and toxic epidermal necrolysis

Stevens-Johnson syndrome and toxic epidermal necrolysis (SJS/TEN) is a rare but life-threatening cutaneous drug reaction mediated by human leukocyte antigen (HLA) class I-restricted CD8+ T cells. For unbiased assessment of cellular immunopathogenesis, here we perform single-cell (sc) transcriptome, surface proteome, and T cell receptor (TCR) sequencing on unaffected skin, affected skin, and blister fluid from 15 SJS/TEN patients. From 109,888 cells, we identify 15 scRNA-defined subsets. Keratinocytes express markers indicating HLA class I-restricted antigen presentation and appear to trigger the proliferation of and killing by cytotoxic CD8+ tissue-resident T cells that express granulysin, granzyme B, perforin, LAG3, CD27, and LINC01871, and signal through the PKM, MIF, TGFβ, and JAK-STAT pathways. In affected tissue, cytotoxic CD8+ T cells express private expanded and unexpanded TCRαβ that are absent or unexpanded in unaffected skin, and mixed populations of macrophages and fibroblasts express pro-inflammatory markers or those favoring repair. This data identifies putative cytotoxic TCRs and therapeutic targets.

Cytokine and Chemokine Receptor Profiles in Adipose Tissue Vasculature Unravel Endothelial Cell Responses in HIV

Chronic systemic inflammation contributes to a substantially elevated risk of myocardial infarction in people living with HIV (PLWH). Endothelial cell dysfunction disrupts vascular homeostasis regulation, increasing the risk of vasoconstriction, inflammation, and thrombosis that contribute to cardiovascular disease. Our objective was to study the effects of plasma from PLWH on endothelial cell (EC) function, with the hypothesis that cytokines and chemokines are major drivers of EC activation. We first broadly phenotyped chemokine and cytokine receptor expression on arterial ECs, capillary ECs, venous ECs, and vascular smooth muscle cells (VSMCs) in adipose tissue in the subcutaneous adipose tissue of 59 PLWH using single cell transcriptomic analysis. We used CellChat to predict cell-cell interactions between ECs and other cells in the adipose tissue and Spearman correlation to measure the association between ECs and plasma cytokines. Finally, we cultured human arterial ECs (HAECs) in plasma-conditioned media from PLWH and performed bulk sequencing to study the direct effects ex-vivo. We observed that arterial and capillary ECs expressed higher interferon and tumor necrosis factor (TNF) receptors. Venous ECs had more interleukin (IL)-1R1 and ACKR1 receptors, and VSMCs had high significant IL-6R expression. CellChat predicted ligand-receptor interactions between adipose tissue immune cells as senders and capillary ECs as recipients in TNF-TNFRSF1A/B interactions. Chemokines expressed largely by capillary ECs were predicted to bind ACKR1 receptors on venous ECs. Beyond the adipose tissue, the proportion of venous ECs and VSMCs were positively plasma IL-6. In ex-vivo experiments, HAECs cultured with plasma-conditioned media from PLWH expressed transcripts that enriched for the TNF-α and reactive oxidative phosphorylation pathways. In conclusion, ECs demonstrate heterogeneity in cytokine and chemokine receptor expression. Further research is needed to fully elucidate the role of cytokines and chemokines in EC dysfunction and to develop effective therapeutic strategies.

Multiomic single-cell sequencing defines tissue-specific responses in Stevens-Johnson Syndrome and Toxic epidermal necrolysis

Stevens-Johnson syndrome and toxic epidermal necrolysis (SJS/TEN) is a rare but life-threatening cutaneous drug reaction mediated by human leukocyte antigen (HLA) class I-restricted CD8+ T-cells. To obtain an unbiased assessment of SJS/TEN cellular immunopathogenesis, we performed single-cell (sc) transcriptome, surface proteome, and TCR sequencing on unaffected skin, affected skin, and blister fluid from 17 SJS/TEN patients. From 119,784 total cells, we identified 16 scRNA-defined subsets, confirmed by subset-defining surface protein expression. Keratinocytes upregulated HLA and IFN-response genes in the affected skin. Cytotoxic CD8+ T-cell subpopulations of expanded and unexpanded TCRαβ clonotypes were shared in affected skin and blister fluid but absent or unexpanded in SJS/TEN unaffected skin. SJS/TEN blister fluid is a rich reservoir of oligoclonal CD8+ T-cells with an effector phenotype driving SJS/TEN pathogenesis. This multiomic database will act as the basis to define antigen-reactivity, HLA restriction, and signatures of drug-antigen-reactive T-cell clonotypes at a tissue level.

The pathogenesis of obesity in people living with HIV

PURPOSE OF REVIEW

The public health challenge of overweight and obesity increasingly affects people living with HIV (PWH). These effects have also accelerated as the prevalence of antiretroviral therapy (ART) use has increased among PWH. It is therefore also critical that we examine and understand the pathogenesis of obesity among PWH.This review will aim to summarize relevant and recent literature related to the risks of weight gain and obesity associated with HIV disease progression, cardiometabolic disease, and multimorbidity among PWH. Further, we will discuss adipose tissue changes associated with weight gain and obesity and how these changes relate to metabolic complications.

RECENT FINDINGS

Several observational and experimental studies in recent years have evaluated the role of contemporary ART regimens, particularly integrase strand transfer inhibitors (INSTIs) and tenofovir alafenamide (TAF), as contributors to weight gain, obesity, and cardiometabolic disease, though the mechanisms remain unclear. Metabolic dysregulation has also been linked to ectopic fat deposition and alterations in innate and adaptive immune cell populations in adipose tissue that accompany HIV and obesity. These factors continue to contribute to an increasing burden of metabolic diseases in an aging HIV population.

SUMMARY

Obesity accompanies an increasing burden of metabolic disease among PWH, and understanding the role of fat partitioning and HIV and ART-related adipose tissue dysfunction may guide prevention and treatment strategies.