Bombesin receptor-activated protein homolog deficiency altered the pattern of pathological changes of psoriasis - like skin lesion in mice.

This study investigated the potential role of the mouse homolog of bombesin receptor-activated protein (BRAP) in imiquimod (IMQ) induced psoriasis - like skin inflammation. The expression of both human BRAP, encoded by C6orf89, and its mouse homolog, encoded by BC004004, has been found to be expressed abundantly in the keratinocytes. BC004004 knockout mice (BC004004-/-) were topically treated with IMQ daily for 7 days to test whether they were more vulnerable to psoriasis - like inflammation. We found that those mice exhibited an altered pattern of inflammation process compared to isogenic wild type control mice (BC004004+/+). BC004004-/- mice developed skin lesions with earlier and more acute onset, as well as a quicker remission. The cytokines related to pathogenesis of psoriasis also exhibited different expression patterns in IMQ treated BC004004-/- mice. On day 4 of IMQ treatment, BC004004-/- mice exhibited a higher expression level of IL-17A compared to BC004004+/+ mice, suggesting a more robust activation of Th17 cells in the knockout mice. The serum level of thymic stromal lymphopoietin (TSLP), one of the keratinocyte derived cytokines, was also increased in BC004004-/- mice and reached its peak on day 4. Knockdown of BRAP in cultured human keratinocyte-derived HaCaT cells by siRNA silencing led to increased release of TSLP. Our data suggest that the elevated of level of TSLP released from keratinocytes due to BRAP deficiency might mediate the crosstalk between the epidermal cells and immune cells and thereby contributing to the altered pathological changes observed in psoriasis - like skin lesion in knockout mice.

Attenuation of renal fibrosis in mice due to lack of bombesin receptor-activated protein homologue.

Bombesin receptor-activated protein (BRAP), encoded by the C6orf89 gene in humans, is expressed in various cells with undefined functions. BC004004, the mouse homologue of C6orf89, has been shown to play a role in bleomycin-induced pulmonary fibrosis through the use of a BC004004 gene knockout mouse (BC004004-/-). In this study, we investigated the potential involvement of BRAP in renal fibrosis using two mouse models: unilateral ureteral obstruction (UUO) and type 2 diabetes mellitus induced by combination of a high-fat diet (HFD) and streptozocin (STZ). BRAP or its homologue was expressed in tubular epithelial cells (TECs) in the kidneys of patients with chronic kidney disease (CKD) and in BC004004+/+ mice. Compared to control mice, BC004004-/- mice exhibited attenuated renal injury and renal fibrosis after UUO or after HFD/STZ treatment. Immunohistochemistry and immunoblot analyses of the kidneys of BC004004+/+ mice after UUO surgery showed a more significant decrease in E-cadherin expression and a more significant increase in both α smooth muscle actin (α-SMA) and vimentin expression compared to BC004004-/- mice. Additionally, stimulation with transforming growth factor-ß1 (TGF-ß1) led to a more significant decrease in E-cadherin expression and a more significant increase in α-SMA and vimentin expression in isolated TECs from BC004004+/+ than in those from BC004004-/- mice. These results suggest that an enhanced epithelial-mesenchymal transition (EMT) process occurred in TECs in BC004004+/+ mice during renal injury, which might contribute to renal fibrosis. The loss of the BRAP homologue in BC004004-/- mice suppressed EMT activation in kidneys and contributed to the suppression of fibrosis during renal injury.

Lack of bombesin receptor-activated protein homologous protein impairs hippocampal synaptic plasticity and promotes chronic unpredictable mild stress induced behavioral changes in mice.

Bombesin receptor-activated protein (BRAP) and its homologous protein in mice, which is encoded by bc004004 gene, were expressed abundantly in brain tissues with unknown functions. We treated bc004004-/- mice with chronic unpredictable mild stress (CUMS) to test whether those mice were more vulnerable to stress-related disorders. The results of forced swimming test, sucrose preference test, and open field test showed that after being treated with CUMS for 28 days or 35 days both bc004004-/- and bc004004+/+ mice exhibited behavioural changes and there was no significant difference between bc004004+/+ and bc004004-/-. However, behavioural changes were observed only in bc004004-/- mice after being exposed to CUMS for 21 days, but not in bc004004+/+ after 21-day CUMS exposure, indicating that lack of BRAP homologous protein may cause vulnerability to stress-related disorders in mice. In addition, bc004004-/- mice showed a reduction in recognition memory as revealed by novel object recognition test. Since memory changes and stress related behavioural changes are all closely related to the hippocampus function we further analyzed the changes of dendrites and synapses of hippocampal neurons as well as expression levels of some proteins closely related to synaptic function. bc004004-/- mice exhibited decreased dendritic lengths and increased amount of immature spines, as well as altered expression pattern of synaptic related proteins including GluN2A, synaptophysin and BDNF in the hippocampus. Those findings suggest that BRAP homologous protein may have a protective effect on the behavioural response to stress via regulating dendritic spine formation and synaptic plasticity in the hippocampus.

Bombesin Receptor-Activated Protein (BRAP) Modulates NF-κB Activation in Bronchial Epithelial Cells by Enhancing HDAC Activity.

Our previous studies provided evidence that bombesin receptor-activated protein (BRAP), encoded by C6ORF89, is widely expressed in human airway epithelial cells and may play a role in the stress response of lung epithelia. In this study, we demonstrated that BRAP has a regulatory effect on NF-κB transcriptional activity in cultured human bronchial epithelial cells (HBECs). BRAP overexpression by gene transfer inhibited both basal and inducible NF-κB transcriptional activity in HBECs, whereas BRAP knockdown had the opposite effect. BRAP was shown to regulate NF-κB activity by enhancing histone deacetylase (HDAC) activity. In addition, BRAP might increase HDAC activity that leads to NF-κB activation via its putative C-terminal domain. Our study suggests that the BRAP protein is an important regulator of immune and inflammatory responses in the human airway epithelium.

Epidemiology of Irritable Bowel Syndrome in a Large Academic Safety-Net Hospital.

(1) Background: Irritable bowel syndrome (IBS) is a highly prevalent disorder of gut-brain interaction (DGBI) that is known to reduce the quality of life and raise healthcare costs. The aim of this study was to describe the epidemiology of IBS in a large multiracial academic safety-net hospital. (2) Methods: An electronic query was performed using ICD-9 codes to identify 740 IBS outpatients seen at the Boston Medical Center (BMC) between 1 January 2005 and 30 September 2007. Demographic data were collected from electronic medical records. Bivariate analyses using chi-square tests and ANOVA were used to calculate the significance of categorical and continuous dependent variables, respectively. (3) Results: Compared with the general BMC outpatient population, the IBS cohort consisted of significantly higher proportions of White and Asian patients and lower proportions of Black and Hispanic patients (p < 0.0001). White and Asian patients predominantly had private insurance, while Black and Hispanic patients mostly had government/state-funded or no insurance (p < 0.0001). The IBS subgroup frequencies were similar across racial groups; however, Hispanic patients had IBS with constipation (32%, p < 0.02) more often compared to non-Hispanic patients. (4) Conclusions: Significant differences were found across the racial groups studied in this large outpatient IBS cohort. These findings are likely attributed to racial and socioeconomic disparities in healthcare access and utilization.

Co-Morbidities of Irritable Bowel Syndrome in a Racially and Ethnically Diverse Population.

Introduction: Irritable bowel syndrome (IBS) is a disorder of gut-brain interaction (DGBI), and associated co-morbidities worsen quality of life. Research concerning IBS co-morbidities in different racial/ethnic groups is very sparse. This study aimed to determine the prevalence rates of co-morbidities and possible differences in a multiracial/ethnic IBS cohort. Methods: Based on ICD-9-coded IBS diagnosis, 740 outpatients (≥18 years) were included in this retrospective study at Boston Medical Center. Demographics and ICD-9-coded co-morbidities were extracted from electronic records. Descriptive statistics and multiple logistic regression were used for data analyses. Results: The most prevalent co-morbidities in this IBS cohort included gastroesophageal reflux disorder (GERD) (30%), depression (27%), anxiety (23%), (chronic obstructive pulmonary disease) COPD/asthma (16%), and obesity (10%). GERD was more prevalent in Hispanics and Blacks (p = 0.0005), and non-ulcer dyspepsia (NUD) was more prevalent in Blacks and Asians (p = 0.003). Higher rates of diabetes mellitus type 2 (DMT2) (p = 0.0003) and depression (p = 0.03), but not anxiety (p = 0.9), were present in Blacks and Hispanics. GERD was significantly associated with Hispanics (p = 0.003), dependent on age, overweight, and obesity. NUD was significantly associated with Blacks (p = 0.01) and Asians (p = 0.006), independent of sex, age, and BMI. Cancer of the thyroid, ovaries, and testis occurred at a five-fold higher rate than expected. Conclusions: Significant racial/ethnic differences exist for IBS co-morbidities in this study cohort, including depression, DMT2, GERD, and NUD. Certain cancers were found to be more frequent in this IBS sample as compared with the general population.

Role of bombesin receptor activated protein in the antigen presentation by human bronchial epithelial cells.

Bombesin receptor activated protein (BRAP) was identified in a bacterial two-hybrid screen for proteins interacting with bombesin receptor subtype-3 (BRS-3). We found that BRAP is widely expressed in the airway epithelium of human lungs and may play a role during the stress response of lung epithelium. In this work, we explored the potential roles of BRAP in the antigen presenting function of human bronchial epithelial cells (HBECs). Overexpression of a BRAP recombinant protein in a human bronchial epithelial cell line resulted in a reduction of FITC-OVA uptake by HBECs, which indicated that the antigen uptake ability is inhibited. The analysis of the protein expression of surface molecules including B7 homologs and the major histocompactability complex (MHC) class II molecules showed that the expression levels of HLA-DR and B7DC increased while the levels of B7-H1 and B7.2 decreased. Since those surface molecules are all related to antigen presenting process, the altered expression pattern of those molecules provides further evidence showing that BRAP overexpression leads to a change in antigen presenting function of HBECs. Moreover, overexpression of BRAP in HBECs caused a decrease of co-cultured lymphocytes proliferation and a changed pattern of cytokines produced by lymphocytes in the presence of FITC-OVA, which indicated that changes in the maturation pattern and functions of co-cultured lymphocytes were induced by BRAP overexpression. Overall, our results suggested that overexpression of BRAP may play a role during the antigen presenting process of bronchial epithelium by inhibiting the antigen uptake ability of bronchial epithelial cells.

Report of a Novel Molecular Profile in Malignant Insulinoma.

Pancreatic neuroendocrine tumors, or pNETs, represent a rare and clinically heterogenous subset of pancreatic neoplasms. One such pNET, the insulinoma, is found to be malignant in just 4% of all insulinomas. Due to the exceedingly uncommon occurrence of these tumors, there is controversy regarding the optimal evidence-based management for these patients. We therefore report on a 70-year-old male patient admitted with 3 months of episodic confusion with concurrent hypoglycemia. The patient was found to have inappropriately elevated endogenous insulin levels during these episodes, and somatostatin-receptor subtype 2 selective imaging revealed a pancreatic mass metastatic to local lymph nodes, spleen, and the liver. Fine needle aspiration of pancreatic and liver lesions confirmed the diagnosis of a low grade pancreatic neuroendocrine tumor. Molecular analysis of tumor tissue revealed a novel mutational profile consistent with pNET. The patient was initiated on octreotide therapy. However, treatment with octreotide alone demonstrated limited efficacy in controlling the patient's symptoms, prompting consideration of other therapies.

Irritable Bowel Syndrome and the Gut Microbiome: A Comprehensive Review.

Irritable Bowel Syndrome (IBS) is a functional disorder of the gastrointestinal tract characterized by abdominal pain and altered bowel habits. It has a prevalence of 10 to 25% in the United States and has a high disease burden, as evidenced by reduced quality of life, decreased work productivity and increased healthcare utilization and costs. IBS has been associated with several intra-intestinal and extra-intestinal conditions, including psychiatric comorbidities. Although the pathophysiology of IBS has not been fully elucidated, it involves dysregulation of communication between the brain and gut (brain-gut axis) which is associated with alterations in intestinal motility, gut permeability, visceral hypersensitivity and gut microbiota composition. The purpose of this article is to review the role the gut microbiota plays in the pathophysiology of IBS, understand factors that affect the gut microbiome and explore the microbiome as a target of treatment.

Knockout of the BRAP homolog in mice leads to abnormal tracheal cilia.

Both bombesin receptor-activated protein (BRAP) and its mouse homolog have been found to be expressed in bronchial epithelia but with unclear functions. Using electron microscopy combined with histological assays, we found that BRAP homolog deficiency in mice led to abnormal tracheal cilia. Rab-3A-interacting protein (Rabin8), a protein that might play a role in cilia development, was screened by yeast two-hybrid and further verified to have interaction with human BRAP by co-immunoprecipitation and pulldown assays. The expression levels of Rabin8, together with acetylated α-tubulin, a marker of cilia, were either downregulated by knockdown of BRAP or upregulated by overexpression of BRAP in cultured immortalized human bronchial epithelial cells. These results reveal a role for BRAP in airway cilia formation.

Lack of bombesin receptor-activated protein attenuates bleomycin-induced pulmonary fibrosis in mice.

Bombesin receptor-activated protein (BRAP) was found to express in the interstitial cells of human fibrotic lungs with unknown function. Its homologous protein, encoded by BC004004 gene, was also present in mouse lung tissues. We used BC004004 -/- mice which lack BRAP homologous protein expression to establish a bleomycin-induced lung fibrotic model. After bleomycin treatment, BC004004 -/- mice exhibited attenuation of pulmonary injury and less pulmonary fibrosis. Fibroblasts from BC004004 -/- mice proliferated at a lower rate and produced less collagen. Autophagy-related gene 5 (ATG5) was identified as a partner interacting with human BRAP. Lacking BRAP homologous protein led to enhanced autophagy activity in mouse lung tissues as well as in isolated lung fibroblasts, indicating a negative regulatory role of this protein in autophagy via interaction with ATG5. Enhanced autophagy process in fibroblasts due to lack of BRAP homologous protein might contribute to the resistance of BC004004 -/- mice to pulmonary fibrosis.

Bombesin regulates cyclin D1 expression through the early growth response protein Egr-1 in prostate cancer cells.

Our previous studies indicate that the activation of mitogen-activated protein kinase (MAPK) pathway is involved in bombesin-induced cell proliferation in prostate cancer cells. Cyclin D1 is a critical regulator involved in cell cycle progression through the G1 phase into the S phase, thereby contributing to cell proliferation. Mostly, mitogen-stimulated expression of cyclin D1 is attributed to the extracellular signal-regulated kinase (ERK) activation. Here, we found that bombesin induced human cyclin D1 expression on both mRNA and protein levels in DU-145 prostate cancer cells. Mutational analyses showed that bombesin-enhanced cyclin D1 transcription required the binding of nuclear proteins to the -143 to -105 region of the human cyclin D1 promoter, which contains binding sites for transcription factors Sp-1 and early growth response protein (Egr-1). Do novo protein synthesis was requisite for bombesin-induced cyclin D1 expression. Further studies showed Egr-1 was induced upon bombesin stimulation. The induction of Egr-1 expression and its binding to the cyclin D1 promoter were essential for bombesin-enhanced cyclin D1 transcription. Inhibition of MAPK pathway with either the MEK1 inhibitor PD98059 or a dominant-negative Ras mutant, RasN17, abolished bombesin-induced cyclin D1 activation. Taken together, bombesin-induced cyclin D1 expression in prostate cancer cells is mediated by Egr-1 activation and the interaction of Egr-1 with the Egr-1/Sp1 motif of the cyclin D1 promoter through the activation of MAPK pathway. These findings represent a novel mechanism of bombesin-dependent stimulation of mitogenesis by regulating directly the cell cycle in prostate cancer.