Biology subjects

Kamen, D.

Publications and source records attributed to Kamen, D..

3 recordsLinked to original sources

bioRxiv2023

Macrophage-targeted DNA methyltransferase inhibitor SGI-1027 decreases atherosclerosis in ApoE-null mice

Background and aimsCorrection of vascular DNA hypermethylation may slow atherogenesis. We tested the anti-inflammatory and anti-atherogenic activity of macrophage-targeted DNA methyltransferase (DNMT) inhibitor SGI-1027. Methods, ResultsSGI-1027 was encapsulated into human serum albumin (HSA) nanoparticles (HSANP) functionalized with the PP1 peptide, a macrophage scavenger receptor 1 ligand, fused to a FLAG epitope (S-HSANP-FLAGPP1). Nanoparticle physico-chemical characteristics predicted good marginalization towards the vascular wall, although SGI-1027 encapsulation efficiency was relatively low ([~]23%). S-HSANP-FLAGPP1 were rapidly internalized compared to non-functionalized and, surprisingly, functionalized void controls, and induced a shift towards an anti-inflammatory profile of secreted cytokines in human THP-1 macrophages. S-HSANP-FLAGPP1 colonized the atheroma and induced a significant [~]44% reduction of atherosclerosis burden in the aortic tree of ApoE-null mice compared to controls. A reduction in aortic root atherosclerosis was observed, although primarily induced by HSANP irrespective of loading or functionalization. No alteration of body weight, non-vascular tissue gross histology, plasma glucose, triglyceride or cholesterol were observed. HSA whether free or structured in nanoparticles, induced a 3-4-fold increase in HDL compared to vehicle. ConclusionsWe confirm that DNMT inhibition is anti-atherogenic and provide proof of principle that targeted HSANP are effective carriers for those molecules. SGI-1027 displayed a novel anti-inflammatory activity that is independent of cell proliferation and therefore likely unrelated to DNMT inhibition. HDL elevation may represent an additional advantage of HSA-based nanocarriers.

pathology↗

bioRxiv2023

Intrarenal myeloid subsets associated with kidney injury are comparable in mice and patients with lupus nephritis

Resident macrophages and infiltrating monocytes in kidneys of patients with lupus nephritis are altered both in frequency and function relative to their counterparts in healthy kidneys. The extent to which mouse models might be useful in developing approaches to target these cells for treating lupus nephritis is poorly understood. Here, we studied four common lupus mouse models that share clinical, serologic, and histopathologic kidney changes with humans. Using single-cell profiling and multiplex spatial imaging to analyze the intrarenal myeloid compartment with the onset of clinical disease in these models, we identified monocyte and macrophage subsets that expand or contract in kidneys with clinical nephritis. A unique subset of classical monocytes expanded with the onset of disease and expressed genes such as CD9, Spp1, Ctsd, Cd63, Apoe, and Trem2 that were previously shown to be induced by tissue injury and play a role in inflammation, lipid metabolism and tissue repair in other organs. Resident macrophages transitioned from a pro-inflammatory to a similar injury-associated state with onset of disease. To test whether these findings in mouse models were also observed in humans, we re-analyzed monocytes and macrophages in a single-cell RNAseq dataset of kidney biopsies from 155 patients with lupus nephritis and 30 healthy donors, collected by the NIH AMP RA/SLE consortium. Human monocytes and macrophages showed conserved changes in gene expression programs associated with lupus nephritis disease indices, and localized to similar kidney microenvironments as in mice. By identifying myeloid subsets and disease-associated alterations in biological processes that are conserved across species, we provide a strong rationale for functional studies of these cells and pathways in mice to uncover mechanisms and find targets relevant to human lupus nephritis. One sentence summaryThis study characterizes intrarenal myeloid cells from four lupus mouse models and 155 patients with lupus nephritis using single-cell RNA-seq and imaging, and identifies novel infiltrating and resident myeloid subsets that are conserved between mouse and human lupus nephritis, thus providing a map and strong rationale for functional studies in mice with relevance to human disease.

immunology↗

bioRxiv2022

Differences in the gut permeability marker levels, and abundance and nuclear antigen reactivity of fecal immunoglobulin A (IgA) subclasses in systemic lupus erythematosus patients and healthy controls

Systemic lupus erythematosus (SLE) is characterized by the production of anti-nuclear autoantibodies. Here, for the first time, we show that the abundances of gut permeability marker Zonulin and IgA1- and IgA2-subclasses are significantly higher in the fecal samples of SLE patients compared to HCs. Importantly, IgA-total, IgA1- and IgA2-subclasses from SLE patients showed higher nAg reactivity titers. Notably, we found that not only the nuclear antigen (nAg) reactive fecal IgA1:IgA2 ratio is higher in SLE patients, but also the abundance and nAg reactivity of fecal IgA and subclasses, IgA1 particularly, correlate with the fecal levels of Zonulin, which is produced primarily in the small intestine. These observations suggest that higher amounts of nAg-reactive IgA are produced, particularly, in the proximal gut as indicated by higher IgA1:IgA2 abundance and nAg reactivity ratios and correlation of these features with the Zonulin levels.

immunology↗