Phenotypic and functional characterization of intestinal epithelial exosomes

Intestinal epithelial cells (IEC) are located at a strategic position between the external environment and the most extended lymphoid tissue in the body. Besides their central role in the absorption of nutrients, IEC also provide antigenic information to the immune system and are involved in the balance tolerance/allergy to food antigens. Like professional antigen presenting cells, IEC have been shown to secrete 30- to 90-nm diameter vesicles named exosomes, in a polarized way, either from their apical or basolateral side. These vesicles carry molecules involved in adhesion and antigen presentation, comprising major histocompatibility complex (MHC) class I and class II molecules, tetraspan proteins, CD26/dipeptidyl-peptidase IV, and A33 antigen, a molecule essentially restricted to the intestinal epithelium. Invariant chain, transferrin receptor, and Na-K-ATPase are not expressed on epithelial exosomes. In vivo, in mice, epithelial exosomes carrying MHC/ovalbumin peptide complexes induce specific immune responses when injected intraperitoneally. A33 antigen, an Ig-like molecule highly specific for intestinal epithelial cells and enriched in epithelial exosomes, is found at the surface of cells entering mesenteric lymph nodes suggesting exosome migration from the epithelial layer to the gut associated lymphoid system. Taken together, intestinal epithelial exosomes released at the basolateral surface of enterocytes could be antigen-carrying structures constituting a link between luminal antigens and the local immune system and acting as sensors of the antigenic information present in the intestinal lumen.     

Brief Report: The genetic source tracking of human urinary exosomes

The genetic origins of nanoscale extracellular vesicles in our body fluids remains unclear. Here, we perform a tracking analysis of urinary exosomes via RNA sequencing, revealing that urine exosomes mostly express tissue-specific genes for the bladder and have close cell-genetic relationships to the endothelial cell, basal cell, monocyte, and dendritic cell. Tracking the differentially expressed genes of cancers and corresponding enrichment analysis show urine exosomes are intensively involved in immune activities, indicating that they may be harnessed as reliable biomarkers of noninvasive liquid biopsy in cancer genomic diagnostics and precision medicine.     

Detection of antibodies to small nuclear ribonucleoproteins and small cytoplasmic ribonucleoproteins using unlabeled cell extracts

RNA molecules immunoprecipitated with sera from patients who have rheumatic diseases can be readily detected in polyacrylamide gels by using ethidium bromide and silver stains. With these stains, we found that RNA patterns characteristic of a broad range of specific small nuclear ribonucleoproteins and small cytoplasmic ribonucleoproteins were recognizable. The stains correctly identified antibodies to ribonucleoproteins in 33 (92%) of 36 patient sera selected for study because of known antibody specificities. The silver stain method detected antibodies to ribonucleoproteins in 25 (76%) of 33 patients with classic systemic lupus erythematosus, a frequency that approximated the frequency observed in the Lerner-Steitz assay, which is based on autoradiography. This approach considerably simplifies the latter radioimmunoassay with minimal loss of precision and sensitivity.     

Salivary gland infection: a sex-linked recessive character in tsetse?

Male tsetse, when infected in the laboratory with trypanosomes of the subgenus Trypanozoon, usually produce greater salivary gland infection rates than females of the same species. We show that a single sex-linked gene model can be fitted to most recently published data for salivary gland infection rates in tsetse. The maturation of Trypanosoma congolense infections is shown to be independent of fly sex. The possible effects of genetic control of maturation of Trypanozoon infections in tsetse populations on the transmission of sleeping sickness are considered.     

Salivary gland involvement in chronic pancreatitis of various etiologies

OBJECTIVE: Both the pancreas and salivary glands show many histological and functional similarities. Recently, autoimmune pathogenesis has been postulated in some chronic pancreatitis cases. To examine whether a cell-mediated phenomenon involving the pancreas has a secondary effect on the salivary glands, we assessed the frequency of salivary gland dysfunction in patients with chronic pancreatitis of various etiologies. METHODS: Function of the salivary glands was examined by sialochemistry and salivary gland scintigraphy in patients with chronic pancreatitis (n = 33), Sjogren's syndrome (n = 45), and controls (n = 28). Etiologies of chronic pancreatitis were alcoholic (19 cases), idiopathic (seven cases), and autoimmune (seven cases). RESULTS: Concentrations of Na+, amylase, and beta2-microglobulin in saliva were investigated. In submandibular and parotid gland scintigraphy, time-activity curves were generated, and the ratios of peak count density and washout were calculated.Concentrations of Na+ in saliva of patients with idiopathic chronic pancreatitis and of beta2-microglobulin in saliva of patients with idiopathic and autoimmune chronic pancreatitis were significantly elevated than those of the control group. In submandibular and parotid gland scintigraphy, the peak count density ratio of patients with all chronic pancreatitis and washout ratio of patients with alcoholic and idiopathic chronic pancreatitis were significantly lower than those of the control group. CONCLUSIONS: Salivary gland function was frequently impaired in the course of chronic pancreatitis of various etiologies. Salivary gland dysfunction might be the result of a common pathophysiological effect of alcohol in patients with alcoholic chronic pancreatitis and the aggressive immune mechanism against the pancreatic and the salivary ducts in patients with autoimmune and idiopathic chronic pancreatitis.     

Effect of cereal fibre source and processing on rectal epithelial cell proliferation

Background—Low fat and wheat bran interventionssignificantly reduced the growth of small to large adenomas andmodestly suppressed rectal epithelial cell proliferation in theAustralian Polyp Prevention Project.
Aim—To study the effect of unprocessed wheat bran,unprocessed oat bran and processed wheat bran (Kellogg's All Bran) onrectal epithelial cell proliferation.
Patients—Twenty subjects with recent adenomas anda high fat background diet were recruited.
Methods—Rectal biopsy specimens were taken atentry and at the end of three six-week periods of oat bran (64 g/day),wheat bran (25 g/day) and All Bran (38 g/day), all in associationwith a diet <25% energy as fat, in a randomised cross-over trial.Each of the bran supplements had a total of 11 g dietary fibre. The biopsy specimens were fixed in methacarn and stainedimmunohistochemically for presence of the proliferating cell nuclearantigen (PCNA). The kinetics used to measure proliferation werelabelling index, whole distribution of labelled cells, and labelledcells in the top two-fifths of crypts using analysis of variance.
Results—There were no significant differences inmean labelling indexes between the four diets or in the percentage oflabelled cells in the top two-fifths (p=0.59), but activity in the top two-fifths of crypts was lowest with wheat bran. The mean (SD) labelling indexes were 2.23 (0.11)% for control, 2.13 (0.08)% forwheat bran, 2.19 (0.09)% for oat bran, and 2.12 (0.08)% for All Bran.The proportion in the top two-fifths of the crypts was 2.6 (0.6)% forcontrol, 2.15 (0.5)% for wheat bran, 3.3 (0.9)% for oat bran, and 3.1 (0.9)% for All Bran. On analysis of whole distribution, there was nosignificant overall effect of diets but there was a difference betweensubjects. Analysis including total fibre intake also did not identifyeffects on proliferation.
Conclusion—In this study of high risk subjectswith initial high fat diets, dietary fibre in association with a lowfat diet had no effect on rectal epithelial cell proliferation,although wheat bran had the greatest effect on percentage of labelledcells in the top two-fifths of crypts.

Keywords:cereal fibre; rectal epithelial proliferation; PCNA; fibre solubility

     

Xenopus Ro ribonucleoproteins: members of an evolutionarily conserved class of cytoplasmic ribonucleoproteins.

Ro small ribonucleoproteins consist of a 60-kDa protein and possibly additional proteins complexed with several small RNA molecules. The RNA components of these particles, designated Y RNAs, are about 100 nt long. Although these small ribonucleoproteins are abundant components of a variety of vertebrate species and cell types, their subcellular location is controversial, and their function is completely unknown. We have identified and characterized the Ro RNPs of Xenopus laevis. Three of the four distinct Xenopus Y RNAs appear to be related to the previously sequenced human hY3, hY4, and hY5 RNAs. The fourth Xenopus Y RNA, xY alpha, does not appear to be a homologue of any of the human Y RNAs. Each of the human and Xenopus Y RNAs possesses a conserved stem that contains the binding site for the 60-kDa Ro protein. Xenopus and human 60-kDa Ro proteins are 78% identical in amino acid sequence, with the conservation extending throughout the entire protein. When human hY3 RNA is mixed with Xenopus egg extracts, the human RNA assembles with the Xenopus Ro protein to form chimeric Ro ribonucleoproteins. By analyzing RNA extracted from manually enucleated oocytes and germinal vesicles, we have determined that Y RNAs are located in the oocyte cytoplasm. By examining the distribution of mouse Ro ribonucleoproteins in cytoplast and karyoplast fractions derived from L-929 cells, we have determined that Ro ribonucleoprotein particles also primarily reside in the cytoplasm of mammalian cells.     

A paracrine role for the epithelial progesterone receptor in mammary gland development

Recently generated progesterone receptor (PR)-negative (PR^−/−) mice provide an excellent model for dissecting the role of progesterone in the development of the mammary gland during puberty and pregnancy. However, the full extent of the mammary gland defect in these mice caused by the absence of the PR cannot be assessed, because PR^−/− mice do not exhibit estrous cycles and fail to become pregnant. To circumvent this difficulty, we have transplanted PR^−/− breasts into wild-type mice, and we have demonstrated that the development of the mammary gland in the absence of the PR is arrested at the stage of the simple ductal system found in the young virgin mouse. Mammary transplants lacking the PR in the stromal compartment give rise to normal alveolar growth, whereas transplants containing PR^−/− epithelium conserve the abnormal phenotype. Chimeric epithelia in which PR^−/− cells are in close vicinity to PR wild-type cells go through complete alveolar development to which the PR^−/− cells contribute. Together, these results indicate that progesterone acts by a paracrine mechanism on a subset of mammary epithelial cells to allow for alveolar growth and that expression of the PR is not required in all the cells of the mammary epithelium in order for alveolar development to proceed normally.     

The role of exosomes on colorectal cancer: A review

Exosomes are extracellular microvesicles released from cells, which are involved in many biological and pathological processes, mainly because of their role in intercellular communication. Exosomes derived from colorectal cancer (CRC) cells are related to oncogenesis, tumor cell survival, chemo‐resistance, and metastasis. The role of the exosomes in these processes involves the transfer of proteins, RNAs, or mutant versions of proto‐oncogenes to the target cells. In recent years, great efforts have been made to identify useful biomarkers in CRC exosomes for diagnosis, prediction of prognosis, and treatment response. This review focuses on recent studies on CRC exosomes, considering isolation, cargo, biomarkers, and the effects of exosomes on the development and progression of CRC, including resistance to antitumor therapy.     

Salivary gland involvement and oxidative stress in juvenile idiopathic arthritis: novel observation in oligoarticular-type patients

OBJECTIVE: The salivary glands may become affected in various collagen diseases, but their involvement in juvenile idiopathic arthritis (JIA) has received little attention. We studied the salivary composition and the antioxidant profile in patients with JIA, as well as their serum antioxidant status. METHODS: Twenty-two children with JIA according to the American College of Rheumatology criteria (10 oligoarticular, 7 polyarticular, and 5 systemic-type) and 15 healthy controls were studied. Serum and saliva samples were obtained simultaneously and analyzed. RESULTS: Significantly raised levels of antioxidant enzyme activity were observed in the patients with JIA, in both saliva and serum. The salivary peroxidase activity was significantly higher in the total group of patients with JIA by 8.5% (p < 0.01) as compared to controls (0.76 vs 0.70 mU/ml). Salivary superoxide dismutase was found to be significantly increased mainly in the patients with systemic JIA (by 74%; p < 0.02). Significantly higher levels of peroxidase activity were observed in serum of patients with JIA, particularly of the polyarticular group, by 17% (p < 0.05). Major changes in saliva composition were observed in patients with oligoarticular disease compared to controls: the patients had a lower salivary flow by 33%, less acidic saliva, and significantly lower salivary levels of magnesium by 44% (p < 0.01), total protein by 44% (p < 0.02), amylase by 34% (p < 0.02), and lactate dehydrogenase by 62% (p < 0.02). CONCLUSION: Children with JIA exhibited a major increase in antioxidant enzyme activity, both in serum and in saliva. Patients with oligoarticular JIA displayed indications of significant and specific damage to the salivary glands, a novel observation.