Differentiation-linked changes in tyrosine phosphorylation, functional activity, and gene expression downstream from the granulocyte- macrophage colony-stimulating factor receptor

The HL-60 model of myeloid maturation was used to test whether changes in signaling from the granulocyte-macrophage colony-stimulating factor (GM-CSF) receptor accompany maturation-related changes in cellular responses to GM-CSF. Receptor expression, tyrosine phosphorylation, functional activity, and c-fos gene expression were measured. Functional GM-CSF receptors were present throughout differentiation as both uninduced and dimethyl sulfoxide (DMSO)-induced HL-60 cells responded to GM-CSF, albeit in different ways. Uninduced promyelocytes proliferated in response to GM-CSF, whereas DMSO-induced cells lost the capacity to proliferate but did respond with increased expression of beta 2-integrins, enhanced respiratory burst activity, and metabolism of arachidonic acid. GM-CSF-stimulated upregulation of c-fos mRNA expression was not detected in immature cells but developed after 2 to 4 days with DMSO in line with a marked increase in responsiveness to stimulation with phorbol ester, showing that increased expression of c- fos is predominantly a feature of mature phagocytes. GM-CSF stimulated the tyrosine phosphorylation of a broadly similar range of proteins in both uninduced and DMSO-treated HL-60 cells, but protein bands were more heavily phosphorylated in DMSO-induced cells. Phosphorylation was rapid in onset and very transient in immature cells. Phosphorylation of several proteins, in particular a 130-kD band, was more sustained in DMSO-induced cells. These differences in signaling were not because of numerical differences in receptors, because reduction of GM-CSF concentration to trigger equivalent numbers of high-affinity receptors delayed the onset of phosphorylation in DMSO-induced cells. We conclude that there are maturation-related changes in signaling downstream from the GM-CSF receptor.     

Contribution of bone marrow-derived cells to skin: collagen deposition and wound repair

The bone marrow provides inflammatory cells and endothelial progenitor cells to healing cutaneous wounds. To further explore the bone marrow contribution to skin and healing wounds, we used a chimeric mouse model in which the bone marrow from enhanced green fluorescent protein (EGFP) transgenic mice is transplanted into normal C57BL mice. We found that normal skin is a target organ for bone marrow-derived cells from both the hematopoietic and the mesenchymal stem cell pool. We present evidence that the bone marrow contribution to normal skin and the healing cutaneous wound is substantially greater than the previously recognized CD45+ subpopulation, where 15%-20% of the spindle-shaped dermal fibroblasts were bone marrow-derived (EGFP+). Furthermore, the bone marrow-derived cells were able to contract a collagen matrix and transcribe both collagen types I and III, whereas the skin-resident cells transcribed only collagen type I. Whereas endothelial progenitor cells were found early during the wound repair process, bone marrow-derived endothelial cells were not seen after epithelialization was complete. Our data show that wound healing involves local cutaneous cells for reconstituting the epidermis but distant bone marrow-derived cells and the adjacent uninjured dermal mesenchymal cells for reconstituting the dermal fibroblast population.     

Signals mediated by transforming growth factor-beta initiate autoimmune encephalomyelitis, but chronic inflammation is needed to sustain disease

It is unclear whether TGF-beta, a critical differentiation factor for T cells producing interleukin 17 (T(H)-17 cells), is required for the initiation of experimental autoimmune encephalomyelitis (EAE) in vivo. Here we show that mice whose T cells cannot respond to TGF-beta signaling lack T(H)-17 cells and do not develop EAE despite the presence of T helper cell type 1 infiltrates in the spinal cord. Local but not systemic antibody blockade of TGF-beta prevented T(H)-17 cell differentiation and the onset of EAE. The pathogen stimulus zymosan, like mycobacterium, induced T(H)-17 cells and initiated EAE, but the disease was transient and correlated with reduced production of interleukin 23. These data show that TGF-beta is essential for the initiation of EAE and suggest that disease progression may require ongoing chronic inflammation and production of interleukin 23.     

Sexual Functioning in Men With and Without Disabilities: Findings From a Representative Sample of Australian Men

IntroductionStudies on sexual function in men with disabilities have mainly relied on clinical samples; population-based evidence on this topic is limited.AimThe aim of this study was to compare aspects of sexual function between disabled and nondisabled men using a representative sample.MethodsWe used data from Ten to Men, a national cohort study of Australian men aged 18?55 years. We first compared the prevalence of 15 sexual function-related difficulties in disabled vs non-disabled men. Next, we used Poisson regression to examine associations between disability and sexual function. The main analytic sample had 8,496 men. Weights and adjustments appropriate to the sampling methodology were applied. Models adjusted for potential confounders. Results were reported as prevalence ratios (PRs). P values of < .05 were considered statistically significant.Main Outcome MeasureOutcomes were 15 individual items from the National Survey of Sexual Attitudes and Lifestyles-Sexual Function, a validated measure of sexual function with items in 3 domains: physio-psychological aspect; relational aspect; and global self-rating (the 16th item on help-seeking was excluded). These were coded as binary variables denoting past-year sexual problems.ResultsDisabled men had higher prevalence of all outcomes than nondisabled men. 25.6% of men with disabilities and 15.1% of nondisabled men experienced at least 2 of 15 difficulties. The most prevalent problems were “orgasmed too early” (43.8% of disabled men, 37.1% of nondisabled men), imbalance of sexual desire between partners (47.6% of disabled men, 39.2% of nondisabled men), and overall sexual dissatisfaction (39.4% of disabled men, 26.7% of nondisabled men). All adjusted PRs were > 1.00 for disability; associations were statistically significant except “partner experienced sexual difficulties” (PR = 1.23; 95% CI = 0.99?1.53; P = .058) and “orgasmed too early” (PR = 1.16; 95% CI = 1.00?1.35; P = .050). “Presence of discomfort/pain” had the largest adjusted PR for disability (PR = 2.77; 95% CI = 1.89?4.06; P < .001).Clinical ImplicationThis population-based analysis on the relationship between disability and sexual function contextualizes evidence from clinical studies. Findings suggest that disparities between men with and without disability exist but are not uniform across different aspects of sexual function.Strengths & LimitationsTwo major strengths of this study are that the sample included a nondisabled reference group and results are generalizable to Australian men. A key limitation is that disability and sexual function measures are self-reported.ConclusionThis study provides a broad foundation of population-based evidence about sexual function in men with disabilities, relative to men without, showing positive associations between disability and 13 of 15 sexual difficulties.Bollier A-M, King T, Shakespeare T, et al. Sexual Functioning in Men With and Without Disabilities: Findings From a Representative Sample of Australian Men. J Sex Med 2019;16:1749–1757.     

Translational mini-review series on complement factor H: structural and functional correlations for factor H

The 155-kDa glycoprotein, complement factor H (CFH), is a regulator of complement activation that is abundant in human plasma. Three-dimensional structures of over half the 20 complement control protein (CCP) modules in CFH have been solved in the context of single-, double- and triple-module segments. Proven binding sites for C3b occupy the N and C termini of this elongated molecule and may be brought together by a bend in CFH mediated by its central CCP modules. The C-terminal CCP 20 is key to the ability of the molecule to adhere to polyanionic markers on self-surfaces where CFH acts to regulate amplification of the alternative pathway of complement. The surface patch on CCP 20 that binds to model glycosaminoglycans has been mapped using nuclear magnetic resonance (NMR), as has a second glycosaminoglycan-binding patch on CCP 7. These patches include many of the residue positions at which sequence variations have been linked to three complement-mediated disorders: dense deposit disease, age-related macular degeneration and atypical haemolytic uraemic syndrome. In one plausible model, CCP 20 anchors CFH to self-surfaces via a C3b/polyanion composite binding site, CCP 7 acts as a 'proof-reader' to help discriminate self- from non-self patterns of sulphation, and CCPs 1-4 disrupt C3/C5 convertase formation and stability.     

The case for prophylactic cholecystectomy concomitant with gastric restriction for morbid obesity

The pre and postoperative incidence of cholelithiasis were investigated in patients undergoing bariatric surgery at the University of Florida. The first part of the study was retrospective and revealed a pre and 24-month postoperative incidence of cholelithiasis of 30 and 40 percent respectively. Age and postoperative interval were not predictive of cholelithiasis. Patients with cholelithiasis had a significantly greater weight loss (130 +/- 61.0 lbs) than those without stones (109 +/- 59.9 lbs) P = 0.04. Men had a significantly greater weight loss than women (160 +/- 15 lbs SEM versus 99 +/- 7 lbs SEM) as well as a higher incidence of cholelithiasis (53 and 24%, respectively). In the second, prospective part of the study, cholecystectomy was performed in 73 consecutive patients concomitant with their bariatric procedure. Ninety six per cent of removed gallbladders had gross or histologic abnormalities including cholelithiasis in 27 per cent and cholesterolosis/cholecystitis in 69 per cent. The incidence of cholelithiasis was higher than that found in the retrospective series by preoperative ultrasound. The bariatric surgical patient is clearly at risk for the development of postoperative cholelithiasis and cholecystitis. The risk appears to be related to the amount of weight loss. In addition, some gallstones may remain undetected at the time of surgery. We therefore recommend prophylactic cholecystectomy at the time of bariatric surgery.