Search bioRxiv⌕ Search

Biology subjects

Traughber, C. A.

Publications and source records attributed to Traughber, C. A..

6 recordsLinked to original sources

FDA-approved drug library screen identifies antidepressants, antimicrobials, anti-COPD, and anti-CVD agents as blockers of NLRP3 inflammasome and sepsis in a sex-dependent manner.

The NLRP3 inflammasome pathway is central to host defense, but dysregulated activation of inflammasomes promotes diseases associated with metabolic syndrome (diabetes, obesity, CVD, MASLD), neurodegenerative diseases (Alzheimers, Parkinsons), autoinflammatory conditions (CAPS, gout), and respiratory illnesses (asthma/COPD, COVID-19). Therapeutic modulation of NLRP3 is challenging as it requires selective blockade of detrimental inflammasome activation without broadly suppressing innate immunity. Here, we used a phenotypic screen in THP1-ASC-GFP monocytes to identify FDA-approved drugs that can block LPS-induced priming of the NLRP3 inflammasome or inhibit NLRP3 assembly without disrupting upstream priming. Various classes of drugs, such as antidepressants (Fluoxetine, Duloxetine), antihypertensives (Irbesartan, Amlodipine, Nebivolol), antidiabetics (Rosiglitazone), {beta}-adrenergic agonists (Salmeterol), antimalarials (Mefloquine), antifungals (Azoles, Ciclopirox), and antivirals (Saquinavir, Remdesivir), were identified as potent blockers of either priming or assembly of the NLRP3 inflammasome. Secondary validation demonstrated that several compounds suppressed NF-{kappa}B activation, reduced LPS binding to immune cells, decreased pro-inflammatory cytokine production, enhanced efferocytic capacity of macrophages, and enhanced autophagy in vitro and in vivo. Mechanistic analyses further revealed drug-specific effects on lysosomal biogenesis, mitochondrial morphology, and mitochondrial reactive oxygen species. In murine models of acute inflammation and endotoxemia, selected compounds attenuated NLRP3 inflammasome activation, reduced systemic and local inflammatory cytokines, limited tissue injury, and improved survival following LPS-induced sepsis, with efficacy varying by sex. Further studies in primary human cells and in vivo disease models are needed to assess the repurposing and therapeutic relevance of identified drugs.

cell biology↗

Disulfiram reduces atherosclerosis and enhances efferocytosis, autophagy, and atheroprotective gut microbiota in hyperlipidemic mice.

Pyroptosis executor Gasdermin (GsdmD) promotes atherosclerosis in mice and humans. Disulfiram (DSF) was recently shown to potently inhibit GsdmD, but the in-vivo efficacy and mechanism of DSFs anti-atherosclerotic activity is yet to be explored. We used human/mouse macrophages and a hyperlipidemic mouse model of atherosclerosis to determine DSF anti-atherosclerotic efficacy and mechanism. DSF-fed hyperlipidemic apoE-/- mice showed significantly reduced IL-1{beta} release upon in-vivo Nlrp3 inflammasome assembly and showed smaller atherosclerotic lesions ([~]27% and 29% reduction in males and females, respectively). The necrotic core area was also smaller ([~]50% and 46% reduction in DSF-fed males and females, respectively). DSF induced autophagy in macrophages, hepatocytes/liver, and in atherosclerotic plaques. DSF modulated other atheroprotective pathways such as efferocytosis, phagocytosis, and gut microbiota. DSF-treated macrophages showed enhanced phagocytosis/efferocytosis, with a mechanism being a marked increase in cell-surface expression of efferocytic receptor MerTK. Atomic-force microscopy analysis revealed altered biophysical membrane properties of DSF treated macrophages, showing increased ordered-state of the plasma membrane and increased adhesion strength. Furthermore, the 16sRNA sequencing of DSF-fed hyperlipidemic mice showed highly significant enrichment in atheroprotective gut microbiota Akkermansia and a reduction in atherogenic Romboutsia species. Taken together, our data shows that DSF can simultaneously modulate multiple atheroprotective pathways, and thus may serve as novel adjuvant therapeutic to treat atherosclerosis.

cell biology↗

Miltefosine attenuates inflammation, reduces atherosclerosis, and alters gut microbiota in hyperlipidemic mice.

Excess cholesterol induces foam cell formation, NLRP3 inflammasome activation, and IL-1{beta} release in atherosclerotic plaques. We have shown previously that Miltefosine increased cholesterol release and dampened NLRP3 inflammasome assembly in macrophages. Here, we show that Miltefosine reduced LPS-induced choline uptake by macrophages and attenuated NLRP3 inflammasome assembly in mice. Miltefosine-fed mice showed reduced plasma IL-1{beta} in a polymicrobial cecal slurry injection model of systemic inflammation. Miltefosine-fed mice showed increased reverse cholesterol transport from macrophages to plasma, liver, and feces. Hyperlipidemic apoE-/- mice fed with Miltefosine showed significantly reduced weight gain and markedly reduced atherosclerotic lesions vs. control mice. 16S rDNA sequencing and analysis showed alterations in the gut microbiota profile of Miltefosine-fed hyperlipidemic apoE-/- vs. control mice, with the most notable changes in Romboutsia and Bacteroidetes species. Taken together, these data indicate that Miltefosine causes pleiotropic effects on lipid metabolism, inflammasome activity, atherosclerosis, and the gut microbiota.

cell biology↗

Gasdermin D mediates inflammation-induced defects in reverse cholesterol transport and promotes atherosclerosis.

Activation of inflammasomes, such as Nlrp3 and Aim2, can exacerbate atherosclerosis in mice and humans. Gasdermin D (GsdmD) serves as a final executor of inflammasome activity, by generating membrane pores for the release of mature Interleukin-1beta (IL-1{beta}). Inflammation dampens reverse cholesterol transport (RCT) and promotes atherogenesis, while anti-IL-1{beta} antibodies were shown to reduce cardiovascular disease in humans. Though Nlrp3/AIM2 and IL-1{beta} nexus is an emerging atherogenic pathway, the direct role of GsdmD in atherosclerosis is not yet fully clear. Here, we used in-vivo Nlrp3 inflammasome activation to show that the GsdmD-/- mice release ~80% less IL-1{beta} vs WT mice. The GsdmD-/- macrophages were more resistant to Nlrp3 inflammasome mediated reduction in cholesterol efflux, showing ~26% decrease vs. ~60% reduction in WT macrophages. GsdmD expression in macrophages exacerbated foam cell formation in an IL-1{beta} dependent fashion. The GsdmD-/- mice were resistant to Nlrp3 inflammasome mediated defect in RCT, with ~32% reduction in plasma RCT vs. ~ 57% reduction in WT mice, ~ 17% reduction in RCT to liver vs. 42% in WT mice, and ~ 37% decrease in RCT to feces vs. ~ 61% in WT mice. The LDLr anti-sense oligonucleotides (ASO) induced hyperlipidemic mouse model showed the role of GsdmD in promoting atherosclerosis. The GsdmD-/- mice exhibit ~42% decreased atherosclerotic lesion area in females and ~33% decreased lesion area in males vs. WT mice. The atherosclerotic plaque-bearing sections stained positive for the cleaved N-terminal fragment of GsdmD, indicating cleavage of GsdmD in atherosclerotic plaques. Our data show that GsdmD mediates inflammation-induced defects in RCT and promotes atherosclerosis. SummaryGsdmD mediates inflammation-induced defects in RCT and promotes atherosclerosis.

pathology↗

SR-B1 uptake of HDL promotes prostate cancer proliferation and tumor progression

High density lipoprotein (HDL) metabolism, in part, is facilitated by scavenger receptor class B, type 1 (SR-B1) that mediates its uptake into cells. SR-B1 is upregulated in prostate cancer tissue. Here, we report that knockout (KO) of SR-B1 via CRISPR/Cas9 editing led to reduced HDL uptake into prostate cancer cells, and reduced their proliferation in response to HDL. In vivo studies using syngeneic SR-B1 wildtype (SR-B1+/+) and SR-B1 KO (SR-B1-/-) prostate cancer cells in WT and apolipoprotein-AI KO (apoA1-KO) C57BL/6J mice showed that WT hosts, containing higher levels of total and HDL-cholesterol, grew larger tumors than apoA1-KO hosts with lower levels of total and HDL-cholesterol. Furthermore, SR-B1-/- prostate cancer cells formed smaller tumors in WT hosts, than SR-B1+/+ cells in same host model. Tumor volume data was overall similar to survival data. We conclude that tumoral SR-B1 KO reduced HDL-mediated increases in prostate cancer cell proliferation and disease progression.

cancer biology↗

MBOAT7-Driven Phosphatidylinositol Remodeling Promotes the Progression of Clear Cell Renal Cell Carcinoma.

The most common kidney cancer, clear cell Renal Cell Carcinoma (ccRCC) is closely associated with obesity. In fact, the \"clear cell\" variant of RCC is given this name due to large lipid droplets within the tumor cells. Although it is well appreciated that renal lipid metabolism is altered in ccRCC, the mechanisms driving this are not well understood. Leveraging a shotgun lipidomics approach we have identified a lipid signature for ccRCC that includes an increase in arachidonic acid-enriched phosphatidylinositols (AA-PI). In parallel, we found that ccRCC tumors have increased expression of the acyltransferase enzyme membrane bound O-acyltransferase domain containing 7 (MBOAT7) that contributes to AA-PI synthesis. In ccRCC patients, MBOAT7 expression increases with tumor grade, and increased MBOAT7 expression correlates with poor survival. Genetic deletion of MBOAT7 in ccRCC cells decreases proliferation and induces cell cycle arrest, and MBOAT7-/- cells fail to form tumors in vivo. RNAseq of MBOAT7-/- cells identified alterations in cell migration and extracellular matrix organization, which were functionally validated in migration assays. Our work highlights the accumulation of AA-PI in ccRCC and demonstrate a novel way to decrease the AA-PI pool in ccRCC by limiting MBOAT7. Our data reveal that metastatic ccRCC is associated with altered AA-PI metabolism, and identify MBOAT7 as a novel target in advanced ccRCC.

cancer biology↗