Pullman, J. | bioRxiv Science

bioRxiv2023

Detailed Social Network Interactions and Gut Microbiome Strain-Sharing Within Isolated Honduras Villages

When humans assemble into face-to-face social networks, they create an extended environment that permits exposure to the microbiome of other members of a population. Social network interactions may thereby also shape the composition and diversity of the microbiome at individual and population levels. Here, we use comprehensive social network and detailed microbiome sequencing data in 1,098 adults across 9 isolated villages in Honduras to investigate the relationship between social network structure and microbiome composition. Using both species-level and strain-level data, we show that microbial sharing occurs between many relationship types, notably including non-familial and non-household connections. Using strain-sharing data alone, we can confidently predict a wide variety of relationship types (AUC ~0.73). This strain-level sharing extends to second-degree social connections in a network, suggesting the importance of the extended network with respect to microbiome composition. We also observe that socially central individuals are more microbially similar to the overall village than those on the social periphery. Finally, we observe that clusters of microbiome species and strains occur within clusters of people in the village social networks, providing the social niches in which microbiome biology and phenotypic impact are manifested.

microbiology↗

bioRxiv2020

Functional succinate dehydrogenase deficiency is a pathognomonic adverse feature of clear cell renal cancer

BackgroundReduced succinate dehydrogenase (SDH) activity resulting in adverse succinate accumulation was previously thought to be relevant only in 0.05-0.5% of kidney cancers associated with germline SDH mutations (categorized SDH-deficient Renal Cell Carcinoma in the 2016 WHO classification) ResultsWe show that under-expression of SDH subunits resulting in accumulation of oncogenic succinate is a common feature in clear cell renal cell carcinoma (ccRCC) tumors during pathogenesis and progression, with a marked adverse impact on survival in a large cohort (n=516) of ccRCC patients. From a mechanistic standpoint, we show that von Hippel-Lindau (VHL) loss induced hypoxia-inducible factor (HIF) dependent upregulation of mir-210 in ccRCC causes direct inhibition of the SDHD transcript. We demonstrate that reduced expression of SDH subunits is associated with genome-wide increase in methylation and enhancement of epithelial mesenchymal transition (EMT) in ccRCC tumors, consistent with succinate-induced inhibition of TET activity and increase in invasiveness/ migratory ability of ccRCC cells. TET-2 inhibition-induced global regulatory DNA hypermethylation drives SDH loss-induced enrichment of EMT. SDH subunits under-expression had a striking association with CDHI (E-cadherin) loss in ccRCC tumors, in keeping with succinate-induced CDH1 hypermethylation and under-expression in ccRCC cells. Next, in conformity with recombinant TET-2 fluorescence quenching dynamics with succinate and ascorbic acid (AA, a TET enzyme co-factor), AA treatment led to reversal of succinate-induced inhibition of TET activity, CDH1 hypermethylation and under-expression, as well as enhanced invasiveness in ccRCC cells. Furthermore, using immunohistochemical analysis and artificial intelligence quantitation, we report that ccRCC is characterized by a marked loss of ascorbic acid transporter SLC23A1 [median percent positive cells in ccRCC primary tumors (n=104) and normal kidney cortex (n=7) was 0.7 and 32.4 respectively; p=0.0012]. Lower SLC23A1 was associated with worse survival in ccRCC (TCGA). Lastly, intravenous AA significantly prolonged survival in a metastatic ccRCC xenograft model with increased succinate and reduced SLC23A1 expression. ConclusionsTaken together, these findings strongly indicate that functional SDH deficiency is a pathognomonic adverse feature of ccRCC (which accounts for [~]80% of all kidney cancers), and that the WHO category SDH-deficient RCC should be re-named SDH germline mutation-associated RCC. Furthermore, oncogenic accumulation of succinate can be abrogated by TET modulation with AA. STATEMENT OF SIGNIFICANCEIn this study, we show that under-expression of succinate dehydrogenase (SDH) subunits resulting in the accumulation of oncogenic succinate is a common, adverse, epigenetic modulating feature occurring in a vast majority of clear cell renal cell carcinoma (ccRCC), during pathogenesis and progression. Functional SDH deficiency is therefore a pathognomonic feature of ccRCC (which accounts for [~]80% of all kidney cancers), and not just limited to the 0.05-0.5% of kidney cancer patients with germline SDH mutations. Based on the findings reported, we propose that the SDH-deficient RCC category in the 2016 WHO classification of kidney tumors be renamed SDH germline mutation-associated RCC. Furthermore, we demonstrate that oncogenic accumulation of succinate in ccRCC can be countered by TET modulation with ascorbic acid, and that ccRCC is characterized by a marked loss of ascorbic acid transporter SLC23A1. O_FIG O_LINKSMALLFIG WIDTH=172 HEIGHT=200 SRC="FIGDIR/small/188433v2_ufig1.gif" ALT="Figure 1"> View larger version (28K): org.highwire.dtl.DTLVardef@728d5eorg.highwire.dtl.DTLVardef@9f2e24org.highwire.dtl.DTLVardef@8e7011org.highwire.dtl.DTLVardef@15f8d33_HPS_FORMAT_FIGEXP M_FIG Graphical abstract depicting the consequential adverse downregulation of Succinate Dehydrogenase in ccRCC and its central role in oxidative phosphorylation C_FIG

cancer biology↗

bioRxiv2018

Insights from Comparison of the Renal and Skin Single Cell Transcriptomes in Lupus Nephritis

Lupus nephritis (LN) occurs in up to 50% of patients with systemic lupus erythematosus (SLE), and is a major contributor to mortality and morbidity. LN presents as a highly heterogeneous disease both in histopathology and response to therapy. The molecular and cellular processes leading to renal damage and to the heterogeneity of the disease are not well understood. To elucidate the processes underpinning the heterogeneity of LN, we applied singlecell RNA-sequencing (scRNA-seq) to renal biopsies from LN patients. Skin biopsies were evaluated as a source of biomarkers for monitoring kidney disease. Type-I interferon (IFN) response signatures were identified in tubular cells and keratinocytes, differentiating LN patients from healthy controls. Non-responders associated with higher IFN signatures in both tissue compartments. Moreover, non-response was also associated with a fibrotic signature in the tubular cells. Receptor-ligand interaction analysis indicated that the fibrotic process is likely mediated by FGF receptors with the initiating signal originating from infiltrating leukocytes. Differential expression analysis of tubular cells between proliferative and membranous LN pointed to several fibrosis-relevant pathways, which may offer insight into their histological differences. In summary, scRNA-seq was applied to LN to deconstruct its heterogeneity and provide novel targets for personalized approaches to therapy.

immunology↗