Streptococcus gallolyticus subsp. gallolyticus (Sg) has long been known to have a strong association with colorectal cancer (CRC). This knowledge has important clinical implications, and yet little is known about the role of Sg in the development of CRC. Here we demonstrate that Sg promotes human colon cancer cell proliferation in a manner that depends on cell context, bacterial growth phase and direct contact between bacteria and colon cancer cells. In addition, we observed increased level of β-catenin, c-Myc and PCNA in colon cancer cells following incubation with Sg. Knockdown or inhibition of β-catenin abolished the effect of Sg. Furthermore, mice administered with Sg had significantly more tumors, higher tumor burden and dysplasia grade, and increased cell proliferation and β-catenin staining in colonic crypts compared to mice receiving control bacteria. Finally, we showed that Sg is present in the majority of CRC patients and is preferentially associated with tumor compared to normal tissues obtained from CRC patients. These results taken together establish for the first time a tumor-promoting role of Sg that involves specific bacterial and host factors and have important clinical implications.

The intestinal barrier is vulnerable to damage by microbiota-induced inflammation that is normally restrained through mechanisms promoting homeostasis. Such disruptions contribute to autoimmune and inflammatory diseases including inflammatory bowel disease. We identified a regulatory loop whereby, in the presence of the normal microbiota, intestinal antigen-presenting cells (APCs) expressing the chemokine receptor CXCR1 reduced expansion of intestinal microbe-specific T helper 1 (Th1) cells and promoted generation of regulatory T cells responsive to food antigens and the microbiota itself. We identified that disruption of the microbiota resulted in CXCR1 APC-dependent inflammatory Th1 cell responses with increased pathology after pathogen infection. Colonization with microbes that can adhere to the epithelium was able to compensate for intestinal microbiota loss, indicating that although microbial interactions with the epithelium can be pathogenic, they can also activate homeostatic regulatory mechanisms. Our results identify a cellular mechanism by which the microbiota limits intestinal inflammation and promotes tissue homeostasis.

The proteasome processes proteins to facilitate immune recognition and host defense. When inherently defective, it can lead to aberrant immunity resulting in a dysregulated response that can cause autoimmunity and/or autoinflammation. Biallelic or digenic loss-of-function variants in some of the proteasome subunits have been described as causing a primary immunodeficiency disease that manifests as a severe dysregulatory syndrome: chronic atypical neutrophilic dermatosis with lipodystrophy and elevated temperature (CANDLE). Proteasome maturation protein (POMP) is a chaperone for proteasome assembly and is critical for the incorporation of catalytic subunits into the proteasome. Here, we characterize and describe POMP-related autoinflammation and immune dysregulation disease (PRAID) discovered in two unrelated individuals with a unique constellation of early-onset combined immunodeficiency, inflammatory neutrophilic dermatosis, and autoimmunity. We also begin to delineate a complex genetic mechanism whereby de novo heterozygous frameshift variants in the penultimate exon of POMP escape nonsense-mediated mRNA decay (NMD) and result in a truncated protein that perturbs proteasome assembly by a dominant-negative mechanism. To our knowledge, this mechanism has not been reported in any primary immunodeficiencies, autoinflammatory syndromes, or autoimmune diseases. Here, we define a unique hypo- and hyper-immune phenotype and report an immune dysregulation syndrome caused by frameshift mutations that escape NMD.

Cholestatic liver disease is one of the most common metabolic problems associated with total parenteral nutrition (TPN) in preterm infants, and it is strongly related to the duration of TPN ( 1 ). The incidence of parenteral nutrition-associated liver disease (PNALD) in infants who Abstract Total parenteral nutrition (TPN) is associated with the development of parenteral nutrition-associated liver disease (PNALD) in infants. Fish oil-based lipid emulsions can reverse PNALD, yet it is unknown if they can prevent PNALD. We studied preterm pigs administered TPN for 14 days with either 100% soybean oil (IL), 100% fi sh oil (OV), or a mixture of soybean oil, medium chain triglycerides (MCTs), olive oil, and fi sh oil (SL); a group was fed formula enterally (ENT). In TPN-fed pigs, serum direct bilirubin, gamma glutamyl transferase (GGT), and plasma bile acids increased after the 14 day treatment but were highest in IL pigs. All TPN pigs had suppressed hepatic expression of farnesoid X receptor (FXR), cholesterol 7-hydroxylase (CYP7A1), and plasma 7 ␣ -hydroxy-4-cholesten-3-one (C4) concentrations, yet hepatic CYP7A1 protein abundance was increased only in the IL versus ENT group. Organic solute transporter alpha (OST ␣ ) gene expression was the highest in the IL group and paralleled plasma bile acid levels. In cultured hepatocytes, bile acid-induced bile salt export pump (BSEP) expression was inhibited by phytosterol treatment. We show that TPN-fed pigs given soybean oil developed cholestasis and steatosis that was prevented with both This work was supported in part by federal funds from the USDA,, the American Society for Parenteral and Enteral Nutrition, Abbreviations: ALT, alanine aminotransferase; AST, aspartate aminotransferase; BSEP, bile salt export pump; CA, cholic acid; CDCA, chenodeoxycholic acid; C4, 7 ␣ -hydroxy-4-cholesten-3-one; CYP8B1, sterol 12-alpha-hydroxylase; CYP7A1, cholesterol 7-hydroxylase; CYP3A29, cytochrome P450 3A29; CYP27A1, sterol 27-hydroxylase; FGF, fi broblast growth factor; FXR, farnesoid X receptor; GGT, gamma glutamyl transferase; MCT, medium chain triglyceride; MRP3, multidrug resistant protein 3; NTCP, Na + / taurocholate cotransporter; OBCA, obeticholic acid; OST ␣ / ␤ , organic solute transporters alpha and beta; PNALD, parenteral nutrition-associated liver disease; TPN, total parenteral nutrition; UDCA, ursodeoxycholic acid . and immediately placed in cages housed at 31°C to 32°C, as described previously ( 12 ). Based on body weight, pigs delivered from each sow were randomly assigned to one of the three TPN treatment groups or to enteral nutrition (ENT). After delivery, pigs were surgically implanted with catheters into the jugular vein and umbilical artery. Pigs in the enteral group also were implanted with an orogastric feeding tube, whereas TPN groups received a sham puncture. Maternal plasma (16 ml/kg intravenously during the fi rst 24 h) was administered for passive immunological protection. During the 14 day study, pigs received antibiotics (enrofl oxacin 5 mg/kg) intrave...

Alveolar capillary dysplasia with misalignment of pulmonary veins (ACD/MPV) is a rare and lethal developmental disorder of the lung defined by a constellation of characteristic histopathological features. Non-pulmonary anomalies involving organs of gastrointestinal, cardiovascular, and genitourinary systems have been identified in approximately 80% of patients with ACD/MPV. We have collected DNA and pathological samples from more than 90 infants with ACD/MPV and their family members. Since the publication of our initial report of four point mutations and ten deletions, we have identified an additional thirty eight novel nonsynonymous mutations of FOXF1 (nine nonsense, seven frameshift, one inframe deletion, twenty missense, and one no stop). This report represents an up to date list of all known FOXF1 mutations to the best of our knowledge. Majority of the cases are sporadic whereas four familial cases with three showing maternal inheritance, consistent with paternal imprinting of the gene. Twenty five mutations (60%) are located within the putative DNA binding domain, indicating its plausible role in gene regulation. Five mutations map to the second exon. We identified two additional genic and eight genomic deletions upstream to FOXF1. These results corroborate and extend our previous observations and further establish involvement of FOXF1 in ACD/MPV and lung organogenesis.