Project description:Cutibacterium acnes (C. acnes) is a ubiquitous skin commensal bacterium that is generally well tolerated by the immune system. Different strain-types of C. acnes have been reported to be enriched on patients with acne. To understand if these strain-types contribute to skin inflammation, we generated a library of over 200 C. acnes isolates from skin swabs of healthy and acne subjects and assessed their strain-level identity and inflammatory potential. Phylotype II K-type strains were more frequent on healthy and acne non-lesional skin compared to lesional. Phylotype IA-1 C-type strains were dominant on acne lesional skin but absent from healthy. Measurement of host cytokine responses from C. acnes supernatant revealed neither strain-type nor skin-type association predicted inflammatory potential. However, differential proinflammatory responses were induced from identical strain-types, but these differences were not attributable to protease, short chain fatty acid or porphyrin production. Instead, whole genome sequencing revealed the presence of a linear plasmid in high inflammatory strain-types. Intradermal injection of C. acnes in mouse skin revealed a plasmid-associated inflammatory response in dermal fibroblasts, revealed by single-cell RNA sequencing. We conclude that C. acnes strain-type is not sufficient to predict inflammation but other virulence factors including a plasmid may contribute to disease.
Project description:The pathogenesis of acne has been linked to multiple factors such as increased sebum production, inflammation, follicular hyperkeratinization, and the action of Propionibacterium acnes within the follicle. 13-cis Retinoic Acid (13-cis RA, isotretinoin) is the most potent agent in acne treatment. Surprisingly, its mechanism of action in acne is still unknown. Gene expression profiling of skin from 8 patients treated with isotretinoin was performed to gain insights into its mechanism of action. Skin biopsies were obtained from the patients at baseline and at 8 weeks isotretinoin treatment. Gene array expression profiling was conducted using Affymetrix HG-U133A 2.0 arrays in order to examine changes in gene expression as a result of treatment. After treatment, 784 genes were significantly changed: 197 up-regulated and 587 down-regulated. The majority of genes that were up-regulated at 8 weeks encode structural proteins of the extracellular matrix such as collagens, fibulin and fibronectin. The preponderance of genes that were down-regulated at 8 weeks are involved in the metabolism of steroids, cholesterol and fatty acids. Experiment Overall Design: Total 16 chips: 8 baseline/before isotretinoin and 8 after 8 weeks isotretinoin treatment.
Project description:Nutrient limitation in the microenvironment of poorly perfused tumors constrains the metabolism of cancer cells. Identifying these microenvironmental constraints can provide new insight into the nutritional biochemistry of tumors and reveal metabolic liabilities of cancer cells. We have found that limitation of arginine in pancreatic cancers inhibits fatty acid synthesis by suppressing the lipogenic transcription factor SREBP1. SREBP1-driven fatty acid synthesis produces saturated and monounsaturated fatty acids. Producing these fatty acids enables cells to maintain a balance of differently saturated fatty acids needed for lipid homeostasis, even upon exposure to environments enriched in one specific class of fatty acids. Given the constraints on lipid synthesis in the microenvironment, we asked if pancreatic cancers are sensitive to exposure to fats with imbalanced levels of saturated and unsaturated fats. We found microenvironmental constraints on lipid synthesis sensitize pancreatic cancer cells and tumors to exposure to fat sources that are enriched in polyunsaturated fatty acids. Thus, amino acid restriction in the tumor microenvironment constrains lipid metabolism in pancreatic cancer, which renders pancreatic tumors incapable of maintaining lipid homeostasis upon exposure to polyunsaturated-enriched fats.
Project description:Prolonged exposure to a high-fat diet (HFD) exacerbates intestinal disease pathology, yet the early events preceding the development of gut inflammation remain poorly understood. Here we show that within 48 hours, HFD impairs intestinal group 3 innate lymphoid cells (ILC3) and their capacity to produce interleukin-22 (IL-22), critical for maintaining gut homeostasis. This loss of function was associated with rapid dysbiosis, increased gut permeability, and reduced production of antimicrobial peptides, mucus, and tight junction proteins. While saturated fatty acids metabolized through oxidation impaired ILC3 function, unsaturated fatty acids sustained IL-22 secretion by ILC3 through the formation of lipid droplets using DGAT enzymes. Upon inflammation, saturated fatty acids significantly impaired IL-22 production by ILC3 and increased the susceptibility of the gut to injury. Our findings reveal the differential acute impact of saturated and unsaturated fatty acids on gut homeostasis through distinct metabolic pathways in ILC3.
Project description:The pathogenesis of acne has been linked to multiple factors such as increased sebum production, inflammation, follicular hyperkeratinization, and the action of Propionibacterium acnes within the follicle. 13-cis Retinoic Acid (13-cis RA, isotretinoin) is the most potent agent in acne treatment. Surprisingly, its mechanism of action in acne is still unknown. Gene expression profiling of skin from 8 patients treated with isotretinoin was performed to gain insights into its mechanism of action. Skin biopsies were obtained from the patients at baseline and at 8 weeks isotretinoin treatment. Gene array expression profiling was conducted using Affymetrix HG-U133A 2.0 arrays in order to examine changes in gene expression as a result of treatment. After treatment, 784 genes were significantly changed: 197 up-regulated and 587 down-regulated. The majority of genes that were up-regulated at 8 weeks encode structural proteins of the extracellular matrix such as collagens, fibulin and fibronectin. The preponderance of genes that were down-regulated at 8 weeks are involved in the metabolism of steroids, cholesterol and fatty acids. Keywords: drug treatment effects
Project description:The pathogenesis of acne has been linked to multiple factors such as increased sebum production, inflammation, follicular hyperkeratinization, and the action of Propionibacterium acnes within the follicle. In an attempt to understand the specific genes involved in inflammatory acne, we performed gene expression profiling in acne patients. Skin biopsies were obtained from an inflammatory papule and from normal skin in six patients with acne. Biopsies were also taken from normal skin of six subjects without acne. Gene array expression profiling was conducted using Affymetrix HG-U133A 2.0 arrays comparing lesional to nonlesional skin in acne patients and comparing nonlesional skin from acne patients to skin from normal subjects. Within the acne patients, 211 genes are upregulated in lesional skin compared to nonlesional skin. A significant proportion of these genes are involved in pathways that regulate inflammation and extracellular matrix remodeling, and they include matrix metalloproteinases 1 and 3, IL-8, human beta-defensin 4, and granzyme B. These data indicate a prominent role of matrix metalloproteinases, inflammatory cytokines, and antimicrobial peptides in acne lesions. These studies are the first describing the comprehensive changes in gene expression in inflammatory acne lesions and are valuable in identifying potential therapeutic targets in inflammatory acne. Experiment Overall Design: total 18 chips. 6 for acne lesion samples, 6 for normal skin samples, 6 for non-acne patient normal skin samples
Project description:Solid evidence indicates that intake of marine n-3 fatty acids lower serum triglycerides, and that replacing saturated fatty acids (SFA) with polyunsaturated fatty acids (PUFA) reduces plasma total cholesterol and LDL-cholesterol. The molecular mechanisms underlying these health beneficial effects are however not completely elucidated. The aim of this study was to investigate the expression of genes related to lipid metabolism in peripheral blood mononuclear cells (PBMC) depending on the plasma levels of n-6 and n-3 fatty acids and the SFA to PUFA ratio.
Project description:The pathogenesis of acne has been linked to multiple factors such as increased sebum production, inflammation, follicular hyperkeratinization, and the action of Propionibacterium acnes within the follicle. In an attempt to understand the specific genes involved in inflammatory acne, we performed gene expression profiling in acne patients. Skin biopsies were obtained from an inflammatory papule and from normal skin in six patients with acne. Biopsies were also taken from normal skin of six subjects without acne. Gene array expression profiling was conducted using Affymetrix HG-U133A 2.0 arrays comparing lesional to nonlesional skin in acne patients and comparing nonlesional skin from acne patients to skin from normal subjects. Within the acne patients, 211 genes are upregulated in lesional skin compared to nonlesional skin. A significant proportion of these genes are involved in pathways that regulate inflammation and extracellular matrix remodeling, and they include matrix metalloproteinases 1 and 3, IL-8, human beta-defensin 4, and granzyme B. These data indicate a prominent role of matrix metalloproteinases, inflammatory cytokines, and antimicrobial peptides in acne lesions. These studies are the first describing the comprehensive changes in gene expression in inflammatory acne lesions and are valuable in identifying potential therapeutic targets in inflammatory acne. Keywords: acne lesion, normal skin
Project description:Liver sinusoidal endothelial cells (LSEC) are unique endothelial cell typelining the sinusoids of the liver and we have shown that these cells respond in a unique matter when exposed to saturated and unsaturated free fatty acids (FFA) and bile acids. We used microarray to analyze the transcriptional differences between the LSEC exposed to free fatty acids and bile acid receptor agonists to further shed light on their role in non-alcoholic fatty liver disease.