Project description:Fibrosis is vaguely described as connective tissue deposition that can be excessive in pathological conditions. This suggests a quantitative spectrum of fibrosis wherein there can be more or less extracellular matrix (ECM), which in the context of a repairing skin wound could reflect the range from normal scar to keloid. This depiction, however, does not encompass the potential qualitative differences between normal and pathological scars. In keloids, the markedly different physical (hard and dense) and histological (hyalinization) characteristics compared to normal scars indicate an altered and inappropriate matrix, rather than simply too much. With this quantitative discovery-based proteomics we provide a thorough molecular description of keloid lesions relative to normal scars, which is an essential step towards our understanding of this problem.
Project description:Despite recent advances in understanding skin scarring, mechanisms triggering hypertrophic scar formation are still poorly understood. In the present study we performed single-cell sequencing of mature human hypertrophic scars and developing scars in mice. Compared to normal skin, we found significant differences in gene expression in most cell types present in scar tissue. Fibroblasts (FBs) showed the most prominent alterations in gene expression, displaying a distinct fibrotic signature. By comparing genes upregulated in murine FBs during scar development with genes highly expressed in mature human hypertrophic scars, we identified a group of serine proteases, tentatively involved in scar formation. Two of them, dipeptidyl-peptidase 4 (DPP4) and urokinase (PLAU), were further analyzed in functional assays, revealing a role in TGFβ1-mediated myofibroblast differentiation and over-production of components of the extracellular matrix (ECM) without interfering with the canonical TGFβ1 -signaling pathway. In this study, we delineate the genetic landscape of hypertrophic scars and present new insights into mechanisms involved in hypertrophic scar formation. Our data suggest the use of serine protease inhibitors for the treatment of skin fibrosis.
Project description:As tissue macrophages of the central nervous system (CNS), microglia are critically involved in diseases of the CNS. However, it remains unknown what controls their maturation and activation under homeostatic conditions. Here we reveal significant contributions of the host microbiota to microglia homeostasis as germ-free (GF) mice displayed global defects in microglia with altered cell proportions and an immature phenotype leading to impaired innate immune responses. Temporal eradication of host microbiota severely changed microglia properties. Limited microbiota complexity also resulted in defective microglia. In contrast, recolonization with a complex microbiota partially restored microglia features. We determined that short-chain fatty acids (SCFA), microbiota-derived bacterial fermentation products, regulate microglia homeostasis. Accordingly, mice deficient for the SCFA receptor FFAR2 mirrored microglia defects found under GF conditions. These findings reveal that host bacteria vitally regulate microglia maturation and function, whereas microglia impairment can be restored to some extent by complex microbiota. For acute inflammatory challenges, LPS was applied intracranially and 6 hours later, animals were analyzed. Control animals were injected PBS i.c. Transcriptional profiles of FACS-sorted microglia were assessed using Affymetrix® (Santa Clara, USA) GeneChip Arrays (Mouse Gene 2.1 ST Arrays).
Project description:Gut bacterial β-glucuronidases (GUS) promote the toxic side effects of therapeutics by reactivating drugs from their inactive glucuronide conjugates. It is increasingly clear that the interindividual variability of bacterial GUS-producing species in the gut microbiota contributes to differential drug responses. Indeed, the anticancer drug irinotecan exhibits variable clinical toxicity outcomes that have been linked to interindividual differences in the composition of the gut microbiota. However, identification of the specific GUS enzymes responsible for drug metabolism in the context of the complexity of the human fecal microbiota has not been achieved. Here we pinpoint the specific bacterial GUS enzymes that reactivate SN-38, the active metabolite of irinotecan, from complex human fecal microbiota samples with activity-based protein profiling (ABPP). We identify and quantify gut bacterial GUS enzymes from human feces with ABPP-enabled proteomics and then integrate this information with ex vivo kinetics to reveal the specific GUS enzymes responsible for the reactivation of SN-38. The same ABPP approach also reveals the molecular basis for differential gut bacterial GUS inhibition between human fecal samples. Taken together, this work provides an unprecedented pipeline to identify the specific bacterial GUS enzymes responsible for drug-induced GI toxicity from the complexity of human feces, which may serve as highly precise biomarkers of clinical outcomes for irinotecan and other therapeutics.
Project description:Keloid scars is a pathologic fibro-proliferative disorders of the skin, which exhibit abnormal phenotypes including fibroblasts proliferation and collagen deposits. There have been several treatments of keloids including conventional surgical therapies and adjuvant therapies, but a high recurrence rate of keloids was also observed after treatment. Quantitative proteomics approach has been proved an efficient approach to investigate pathological mechanism and novel biomarkers. In this study, we present a label-free quantitative proteomics analysis to explore differential protein expression profiles in normal skin and keloid scar tissues based on nano-liquid chromatography and tandem mass spectrometry (Nano-LC–MS/MS). The study results displayed a more comprehensive keloid protein expression landscape and provided novel pathological insight of keloid.
Project description:Microbiota-induced cytokine responses participate in gut homeostasis, but the cytokine balance at steady-state and the role of individual bacterial species in setting the balance remain elusive. Using gnotobiotic mouse models, we provide a systematic analysis of the role of microbiota in the induction of cytokine responses in the normal intestine. Colonization by a whole mouse microbiota orchestrated a broad spectrum of pro-inflammatory (Th1, Th17) and regulatory T cell responses. Unexpectedly, most tested complex microbiota and individual bacteria failed to efficiently stimulate intestinal cytokine responses. A potent cytokine-inducing function was however associated with non-culturable host-specific species, the prototype of which was the Clostridia-related Segmented Filamentous Bacterium, and this bacterial species recapitulated the coordinated maturation of T cell responses induced by the whole mouse microbiota. Our study demonstrates the non-redundant role of microbiota members in the regulation of gut immune homeostasis. Germfree (GF) female 8-9-week-old mice were gavaged twice at a 24-hr interval with 0.5 mL of fresh anaerobic cultures of fecal homogenate from SFB mono-associated mice, fresh feces from Cv mice (Cvd) or from a healthy human donor (Hum). All mice were sacrificed on d8, 20 and 60 post-colonization in parallel to age-matched Cv and GF controls. RNA was extracted from ileal tissue, and processed to biotin-labelled cRNA, and then hybridized to the NuGO array (mouse) NuGO_Mm1a520177. Microarray analysis compared gene expression in ileum tissue of all the treatment groups GF, Cv, Cvd, Hum and SFB (N=3 per treatment group per time-point). Data was considered significant when P<0.05 using the Benjamini and Hochberg false discovery method.
Project description:The link between human gut microbiota (a complex group of microorganisms including not only bacteria but also fungi, viruses, etc.,) and the physiological state is nowadays unquestionable. Metaproteomic has emerged as a useful technique to characterize this microbial community, not just taxonomically, but also focusing on specific biological processes carried out by gut microbiota that may have an effect in the host health or pathological state. Cystic fibrosis is a genetic disease in which the microbiota of the respiratory tract determines the patient's survival and differences in composition of gut microbiota of cystic fibrosis patients respect to healthy infants have been reported. In order to characterize this host-microbiota inter-relation, we carried out the metaproteomic study of 30 stool samples from infants with cystic fibrosis.
Project description:Microbiota-induced cytokine responses participate in gut homeostasis, but the cytokine balance at steady-state and the role of individual bacterial species in setting the balance remain elusive. Using gnotobiotic mouse models, we provide a systematic analysis of the role of microbiota in the induction of cytokine responses in the normal intestine. Colonization by a whole mouse microbiota orchestrated a broad spectrum of pro-inflammatory (Th1, Th17) and regulatory T cell responses. Unexpectedly, most tested complex microbiota and individual bacteria failed to efficiently stimulate intestinal cytokine responses. A potent cytokine-inducing function was however associated with non-culturable host-specific species, the prototype of which was the Clostridia-related Segmented Filamentous Bacterium, and this bacterial species recapitulated the coordinated maturation of T cell responses induced by the whole mouse microbiota. Our study demonstrates the non-redundant role of microbiota members in the regulation of gut immune homeostasis.
Project description:<p>Emerging evidence that the gut microbiota may contribute in important ways to human health and disease has led us and others to hypothesize that both symbiotic and pathological relationships between gut microbes and their host may be key contributors to obesity and the metabolic complications of obesity. Our "Thrifty Microbiome Hypothesis" poses that gut microbiota play a key role in human energy homeostasis. Specifically, constituents of the gut microbial community may introduce a survival advantage to its host in times of nutrient scarcity, promoting positive energy balance by increasing efficiency of nutrient absorption and improving metabolic efficiency and energy storage. However, in the presence of excess nutrients, fat accretion and obesity may result, and in genetically predisposed individuals, increased fat mass may result in preferential abdominal obesity, ectopic fat deposition (liver, muscle), and metabolic complications of obesity (insulin resistance, hypertension, hyperlipidemia). Furthermore, in the presence of excess nutrients, a pathological transition of the gut microbial community may occur, causing leakage of bacterial products into the intestinal lymphatics and portal circulation, thereby inducing an inflammatory state, further aggravating metabolic syndrome traits and accelerating atherosclerosis. This pathological transition and the extent to which antimicrobial leakage occurs and causes inflammatory and other maladaptive sequelae of obesity may also be influenced by host factors, including genetics. In the proposed study, we will directly test the Thrifty Microbiome Hypothesis by performing detailed genomic and functional assessment of gut microbial communities in intensively phenotyped and genotyped human subjects before and after intentional manipulation of the gut microbiome. To address these hypotheses, five specific aims are proposed: (1) enroll three age- and sex-matched groups from the Old Order Amish: (i) 50 obese subjects (BMI > 30 kg/m2) with metabolic syndrome, (ii) 50 obese subjects (BMI > 30 kg/m2) without metabolic syndrome, and (iii) 50 non-obese subjects (BMI < 25 kg/m2) without metabolic syndrome and characterize the architecture of the gut microbiota from the subjects enrolled in this study by high-throughput sequencing of 16S rRNA genes; (2) characterize the gene content (metagenome) to assess the metabolic potential of the gut microbiota in 75 subjects to determine whether particular genes or pathways are correlated with disease phenotype; (3) characterize the transcriptome in 75 subjects to determine whether differences in gene expression in the gut microbiota are correlated with disease phenotype, (4) determine the effect of manipulation of the gut microbiota with antibiotics on energy homeostasis, inflammation markers, and metabolic syndrome traits in 50 obese subjects with metabolic syndrome and (5) study the relationship between gut microbiota and metabolic and cardiovascular disease traits, weight change, and host genomics in 1,000 Amish already characterized for these traits and in whom 500K Affymetrix SNP chips have already been completed. These studies will provide our deepest understanding to date of the role of gut microbes in terms of 'who's there?', 'what are they doing?', and 'how are they influencing host energy homeostasis, obesity and its metabolic complications? PUBLIC HEALTH RELEVANCE: This study aims to unravel the contribution of the bacteria that normally inhabit the human gastrointestinal tract to the development of obesity, and its more severe metabolic consequences including cardiovascular disease, insulin resistance and Type II diabetes. We will take a multidisciplinary approach to study changes in the structure and function of gut microbial communities in three sets of Old Order Amish patients from Lancaster, Pennsylvania: obese patients, obese patients with metabolic syndrome and non-obese individuals. The Old Order Amish are a genetically closed homogeneous Caucasian population of Central European ancestry ideal for genetic studies. These works have the potential to provide new mechanistic insights into the role of gut microflora in obesity and metabolic syndrome, a disease that is responsible for significant morbidity in the adult population, and may ultimately lead to novel approaches for prevention and treatment of this disorder.</p>