Biology subjects

Tavallaie, M.

Publications and source records attributed to Tavallaie, M..

3 recordsLinked to original sources

bioRxiv2025

Aggressive Cholesterol Lowering Normalizes Atherosclerosis Regression in Jak2V617F Clonal Hematopoiesis

BackgroundThe Jak2V617F (Jak2VF) mutation is an important cause of both clonal hematopoiesis of indeterminate potential (CHIP) and myeloproliferative neoplasms (MPN). Mouse models of Jak2VF CHIP and MPN show accelerated atherosclerosis progression, driven by macrophage inflammasome activation. We undertook the present study to assess the hypothesis that ongoing inflammation would impede atherosclerosis resolution in Jak2VF mice. Methods and ResultsChimeric Jak2VF/WT or control WT/WT bone marrow was transplanted into Ldlr-/-mice and, following 13-16 weeks of Western diet-induced atherosclerosis progression, cholesterol was lowered either moderately (to 200-300 mg/dl) or markedly (to 100 mg/dl). With moderate cholesterol lowering, there was impaired resolution of lesions in Jak2VFMPN mice compared to controls. However, with marked cholesterol lowering, progression of lesions was halted in both Jak2VF MPN and control mice while macrophage burden was decreased and lesional collagen was increased similarly in Jak2VFMPN and control mice. Two mechanisms of low-density lipoprotein (LDL) lowering-induced suppression of inflammation in plaques were implicated: 1) reversal of increased proliferation, DNA damage and Absent in Melanoma 2 (AIM2) inflammasome activation specifically in Jak2VF macrophages and 2) markedly increased macrophage triggering receptor expressed on myeloid cells 2 (TREM2), c-myc expressing macrophages in both Jak2VF and control mice. ConclusionsAggressive LDL lowering reverses inflammasome activation and induces pro-resolving changes in macrophages in Jak2VF MPN, halting atherosclerosis progression and promoting features of plaque stabilization. These findings suggest that aggressive LDL cholesterol lowering could reverse atherosclerotic cardiovascular disease (ACVD) risk in individuals with JAK2VFCHIP or MPN.

molecular biology↗

bioRxiv2025

IL-18 inhibition enlarges lesions, necrotic cores and thickens fibrous caps in Jak2V617F clonal hematopoiesis-driven atherosclerosis.

BackgroundInflammasome activation promotes atherosclerosis in clonal hematopoiesis (CH). Active inflammasomes secrete both IL-1{beta} and IL-18. Plasma IL-18 levels are elevated in Jak2VFCH. Genetic deficiency of IL-18 has been shown to reduce atherosclerosis in non-CH murine models. However, whether IL-18 inhibition promotes atherosclerosis in control or Jak2VF CH is unknown. Methods and resultsLdlr-/- mice were transplanted with bone marrow (BM) from Mx1-cre Jak2VF (20%) and wild-type (80%) mice or with control BM, fed a Western-type diet (WTD) for 8, 10 or 16 weeks and administered control or IL-18 IgG from 4 weeks onwards. IL-18 antibody treatment increased plaque collagen content and cap thickness. Unexpectedly, IL-18 antibody treatment increased the size of early lesions and promoted formation of advanced lesions with large necrotic cores in Jak2VF CH mice. IL-18 antibody treatment was associated with diminished interferon (IFN)-{gamma} and AIM2 levels and reduced macrophage pyroptosis especially in Jak2VF CH mice. However, IL-18 antibodies increased cleaved Caspase-3 and TUNEL+ macrophages (indicating increased apoptosis) and reduced efferocytosis. Sc-RNA-seq analysis showed that IL-18 antibody treatment reduced expression of MHC class II genes, a marker of IFN-{gamma} signaling, and of genes mediating efferocytosis (Mertk and Axl), in resident-like macrophage subpopulations in Jak2VF CH mice. Consistently, IFN-{gamma} injection increased Axl and Mertk expression in resident peritoneal macrophages. ConclusionsDespite improvements in collagen and fibrous cap thickness in Jak2VF CH mice, IL-18 antibody treatment increased advanced necrotic lesions, reflecting a shift from pyroptotic to apoptotic cell death coupled with defective efferocytosis, events which were coordinated by reduced IFN-{gamma} signaling. These findings indicate a mixed atherosclerosis phenotype resulting from IL-18 inhibition, advocating for alternative therapeutic strategies. Inhibition of IL-18 has been considered as a novel therapeutic approach to reduce atherosclerosis and stabilize atherosclerotic plaques. We show that IL-18 antibodies have adverse effects on atherosclerotic lesional necrosis, calling this approach into question. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=169 SRC="FIGDIR/small/657754v1_ufig1.gif" ALT="Figure 1"> View larger version (33K): org.highwire.dtl.DTLVardef@a93b2forg.highwire.dtl.DTLVardef@6cc057org.highwire.dtl.DTLVardef@1c7afc5org.highwire.dtl.DTLVardef@e4da82_HPS_FORMAT_FIGEXP M_FIG C_FIG HighlightsO_LIInflammasome activation produces active IL-1 and IL-18 and worsens atherosclerosis in clonal hematopoiesis (CH) however the contribution of IL-18 is unknown. C_LIO_LIAntibody inhibition of IL-18 increased plaque collagen but also increased early lesion area and late lesions with large necrotic cores in Jak2VF CH mice. C_LIO_LIThere was a reversal of AIM2 inflammasome activation but a switch to apoptosis which along with reduced efferocytosis increased necrosis C_LIO_LIThese events appeared to be coordinated by reduced IFN-{gamma} which increased collagen but also decreased expression of efferocytotic genes. Our studies call into question whether inhibition of IL-18 would stabilize plaques in CH. C_LI

molecular biology↗

bioRxiv2025

Ancient DNA indicates 3,000 years of genetic continuity in the Northern Iranian Plateau, from the Copper Age to the Sassanid Empire

In this study, we present new ancient DNA data from prehistoric and historic populations of the Iranian Plateau. By analysing 50 samples from nine archaeological sites across Iran, we report 23 newly sequenced mitogenomes and 13 nuclear genomes, spanning 4700 BCE to 1300 CE. We integrate an extensive reference sample set of previously published ancient DNA datasets from Western and South-Central Asia, enhancing our understanding of genetic continuity and diversity within ancient Iranian populations. A new Early Chalcolithic sample, predating all other Chalcolithic genomes from Iran, demonstrates mostly Early Neolithic Iranian genetic ancestry. This finding reflects long-term cultural and biological continuity in and around the Zagros area, alongside evidence of some western genetic influence. Our sample selection prioritizes northern Iran, with a particular focus on the Achaemenid, Parthian, and Sassanid periods (355 BCE-460 CE). The genetic profiles of historical samples from this region position them as intermediates on an east-west genetic cline across the Persian Plateau. They also exhibit strong connections to local and South-Central Asian Bronze Age populations, underscoring enduring genetic connections across these regions. Diachronic analyses of uniparental lineages on the Iranian Plateau further highlight population stability from prehistoric to modern times.

genomics↗