Compromised Epithelial Integrity Research Articles

Cytoskeletal and inter-cellular junction remodelling in endometrial organoids under oxygen-glucose deprivation: a new potential pathological mechanism for thin endometria.

What is the pathological mechanism involved in a thin endometrium, particularly under ischaemic conditions? Endometrial dysfunction in patients with thin endometrium primarily results from remodelling in cytoskeletons and cellular junctions of endometrial epithelial cells under ischemic conditions. A healthy endometrium is essential for successful embryo implantation and subsequent pregnancy; ischemic conditions in a thin endometrium compromise fertility outcomes. We recruited 10 patients with thin endometrium and 15 patients with healthy endometrium. Doppler ultrasound and immunohistochemical results confirmed the presence of insufficient endometrial blood perfusion in patients with thin endometrium. Organoids were constructed using healthy endometrial tissue and cultured under oxygen-glucose deprivation (OGD) conditions for 24 h. The morphological, transcriptomic, protein expression, and signaling pathway changes in the OGD organoids were observed. These findings were validated in both thin endometrial tissue and healthy endometrial tissue samples. Endometrial thickness and blood flow were measured during the late follicular phase using transvaginal Doppler ultrasound. Endometrial tissue was obtained via hysteroscopy. Fresh endometrial tissues were used for the generation and culture of human endometrial organoids. Organoids were cultured in an appropriate medium and subjected to OGD to simulate ischemic conditions. Apoptosis and cell death were assessed using Annexin-V/propidium iodide staining. Immunofluorescence analysis, RNA sequencing, western blotting, simple westerns, immunohistochemistry, and electron microscopy were conducted to evaluate cellular and molecular changes. Patients with thin endometrium showed significantly reduced endometrial thickness and altered blood flow patterns compared to those with healthy endometrium. Immunohistochemical staining revealed fewer CD34-positive blood vessels and glands in the thin endometrium group. Organoids cultured under OGD conditions exhibited significant morphological changes, increased apoptosis, and cell death. RNA-seq identified differentially expressed genes related to cytoskeletal remodeling and stress responses. OGD induced a strong cytoskeletal reorganization, mediated by the RhoA/ROCK signaling pathway. Additionally, electron microscopy indicated compromised epithelial integrity and abnormal cell junctions in thin endometrial tissues. Upregulation of hypoxia markers (HIF-1α and HIF-2α) and activation of the RhoA/ROCK pathway were also observed in thin endometrial tissues, suggesting ischemia and hypoxia as underlying mechanisms. none. The study was conducted in an in vitro model, which may not fully replicate the complexity of in vivo conditions. This research provides a new three-dimensional in vitro model of thin endometrium, as well as novel insights into the pathophysiological mechanisms of endometrial ischaemia in thin endometrium, offering potential avenues for identifying therapeutic targets for treating fertility issues related to thin endometrium. This study was supported by the National Natural Science Foundation of China (81925013); National Key Research and Development Project of China (2022YFC2702500, 2021YFC2700303, 2021YFC2700601); the Capital Health Research and Development Project (SF2022-1-4092); the National Natural Science Foundation of China (82288102, 81925013, 82225019, 82192873); Special Project on Capital Clinical Diagnosis and Treatment Technology Research and Transformation Application (Z211100002921054); the Frontiers Medical Center, Tianfu Jincheng Laboratory Foundation(TFJC2023010001). The authors declare that no competing interests exist.

#4947 LMO7 IN URINE AS A SPECIFIC MARKER OF COMPROMISED RENAL EPITHELIAL INTEGRITY

Abstract Background and Aims Renal epithelial barrier (REB) are the physical isolator as well as physiological interface mediating body fluid and electrolytes homeostasis. Maintaining epithelial integrity is tightly related to REB biological function. LMO7 (LIM domain only 7) is a protein associated with the cell–cell junctional complex and is predominantly distributed in renal tubular epithelial cells. Previously, we reported that the LMO7 is associated with the maintenance of renal epithelial integrity, and that LMO7 releases to conditioned medium when the epithelial integrity was lost. In this study, we attempt to characterize roles of LMO7 and its functional interacting protein in maintaining epithelial integrity, and relevance of the LMO7 released from plasma membrane and the loss of tubular epithelial integrity. Method Renal ischemia-reperfusion injury (IRI) in mice as a model of acute kidney injury (AKI) were settled as a platform to investigate the the roles of LMO7 and its functional interacting protein in the pathological progression of compromised tubular epithelial integrity. Additionally, renal epithelial cells cultured in hypoxia as the pathogenic condition equivalent to AKI were also employed to investigate the role of LMO7. We also search the STRING database with LMO7 as query to find out its functional interacting proteins. Pathological pattern associated with LMO7 and its functional interacting protein in mice suffering from AKI as well as loss of tubular epithelial integrity were examined by immunofluorescent visualization. The LMO7 in urine as well as in conditioned medium derived from medium of hypoxia culture were quantified by Western blot analysis. Results Renal damage in IRI mice showed loss of epithelial integrity by histochemical staining, presence of LMO7 in urine, and high serum creatinine on the third day post IRI. Under the periodic acid-schiff (PAS) staining, loss of epithelial integrity is visible in proximal tubules, Henle's loops, and collecting ducts at the third day after reperfusion, and brush border impairment is observed in the outer stripe of the outer medulla. Most severe damages in renal tubules are present in Henle's loops where the epithelia express abundant LMO7. In the AKI mice, the LMO7 in renal tubules was apparently lower in Henle's loops. Additionally, the VANGL1, a LMO7 interacting protein participated in epithelial integrity and planar cell polarity in kidney, is also absent in Henle's loop of AKI mice. Hypoxia and glucose deprivation in cultured renal epithelial cells resulted in loss of epithelial integrity, and down-regulation of LMO7 and VANGL1. LMO7 was also identified in conditioned medium in which cells exposed to hypoxia but not normoxia. Additionally, the LMO7 was detected in urine of some patients with chronic kidney disease. Conclusion Presence of LMO7 in urine has been promising in experimental models holding compromised epithelial integrity. These approaches identified the role of LMO7 in maintaining epithelial integrity and that LMO7 being released into urine after renal epithelial damage as a novel marker for loss of REB.

Mechanical stress driven by rigidity sensing governs epithelial stability.

Epithelia act as a barrier against environmental stress and abrasion and in vivo they are continuously exposed to environments of various mechanical properties. The impact of this environment on epithelial integrity remains elusive. By culturing epithelial cells on 2D hydrogels, we observe a loss of epithelial monolayer integrity through spontaneous hole formation when grown on soft substrates. Substrate stiffness triggers an unanticipated mechanical switch of epithelial monolayers from tensile on soft to compressive on stiff substrates. Through active nematic modelling, we find that spontaneous half-integer defect formation underpinning large isotropic stress fluctuations initiate hole opening events. Our data show that monolayer rupture due to high tensile stress is promoted by the weakening of cell-cell junctions that could be induced by cell division events or local cellular stretching. Our results show that substrate stiffness provides feedback on monolayer mechanical state and that topological defects can trigger stochastic mechanical failure, with potential application towards a mechanistic understanding of compromised epithelial integrity during immune response and morphogenesis.

An overview on the RSV-mediated mechanisms in the onset of non-allergic asthma.

Respiratory syncytial virus (RSV) infection is recognized as an important risk factor for wheezing and asthma, since it commonly affects babies during lung development. While the role of RSV in the onset of atopic asthma is widely recognized, its impact on the onset of non-atopic asthma, mediated via other and independent causal pathways, has long been also suspected, but the association is less clear. Following RSV infection, the release of local pro-inflammatory molecules, the dysfunction of neural pathways, and the compromised epithelial integrity can become chronic and influence airway development, leading to bronchial hyperreactivity and asthma, regardless of atopic status. After a brief review of the RSV structure and its interaction with the immune system and neuronal pathways, this review summarizes the current evidence about the RSV-mediated pathogenic pathways in predisposing and inducing airway dysfunction and non-allergic asthma development.

Gut Microbiota and Type 1 Diabetes Mellitus: The Effect of Mediterranean Diet.

Type 1 diabetes mellitus (T1DM) is a chronic autoimmune disease resulting from a complex interplay between genetic susceptibility and environmental factors. Regarding the latter, gut microbiota has a pivotal role in the pathogenesis of T1DM, by affecting intestinal permeability, molecular mimicry, and modulating innate and adaptive immune system, as described in several previous studies. The composition of the gut microbiota is largely influenced by diet. Some observational studies have shown that a low fiber intake is associated with the development of many inflammatory and immune-mediated diseases. In this context, the Mediterranean diet (MD), which is based on high consumption of cereals (preferably as whole grains), legumes, nuts, vegetables, fruits, olive oil, and fish, could play a protective role. Many of the characteristic components of MD have functional characteristics with positive effects on health and well-being. Eating habits are the main significant determinants of the microbial multiplicity of the intestine and the food components influence both microbial populations and their metabolic activities from the early stages of life. Moreover, food metabolites influence the immune response. The intestine is considered the primary site where food metabolites mediate their effects, through epithelial integrity or mucosal immunity. The compromised epithelial integrity allows the translocation of bacteria and/or the diffusion of their products, such as food antigens and lipopolysaccharides, from the intestinal lumen to the tissues, which could enhance the stimulation of immune cells, contributing to the pathogenesis of autoimmune diseases, such as T1DM. The intake of a high amount of fiber and therefore of prebiotics with MD allows the microbiota to have a good microbial balance. Moreover, as more dietary fibers are ingested, a higher amount of short-chain fatty acids (SCFAs) is produced by anaerobic gut microbiota, promoting gut homeostasis, to which also contribute tryptophan metabolites and omega-3-fatty acids. Furthermore, the higher intake of polyunsaturated fatty acids and omega-3-fatty-acids contribute to a better metabolic control. In this review we report the relationship between gut microbiota and T1DM and we explore the effects of Mediterranean diet on microbiota as a potential therapeutic strategy, aimed at preventing or delaying progression of T1DM and its complications.

Development and Assessment of a Novel Canine Ex Vivo Corneal Model

ABSTRACTPurpose: To develop a novel ex vivo extended culture model of canine corneal epithelial cell wound healing.Materials and Methods: Canine corneoscleral rims (CSR) were obtained and, after preparation for culture, were placed on a nutating scaffold and incubated in physiological conditions. In experiment 1, eight CSR in a serum-containing antimicrobial-fortified medium were monitored for epithelial integrity and bacterial infection up to 28 days in culture. CSR were assessed histologically at the end of the culture period end points 0, 7, 14, and 28 days with accompanying scanning electron microscopic (SEM) and transmission electron microscopic (TEM) evaluation. Samples for microbial culture were obtained at days 0, 3, 7, 14, and 28. In experiment 2, uniform 8-mm-diameter superficial corneal epithelial wounds were created and monitored for re-epithelialization in the same culture conditions or in a serum-free protein equivalent medium, with four CSR per group. Standardized digital images were obtained with cobalt filter at the time of fluorescein staining and media change every six hours. Image J imaging software was used to measure the area of fluorescein retention. Re-epithelialization rates were calculated and CSR then fixed for immunohistochemistry (IHC).Results: All corneas survived to end points as described in experiment 1 with no evidence of contamination or compromised epithelial integrity. Histologically, a multilayered epithelium was maintained and corneal edema was not appreciated until day 14. SEM examination revealed epithelial cell layer confluence and migrating epithelial cells of normal cellular morphology with normal cell–cell interactions on TEM. In experiment 2, all eight corneas healed with a healing rate of 0.702 ± 0.130 mm2/h (1.25 mm/day epithelial cell migration rate) and were positive in IHC evaluation for markers of corneal fibrosis.Conclusion: This ex vivo canine corneal wound healing model is an appropriate and clinically relevant tool for assessment and modulation of epithelial wound healing.

The intestinal epithelial barrier: a therapeutic target?

A fundamental function of the intestinal epithelium is to act as a barrier that limits interactions between luminal contents such as the intestinal microbiota, the underlying immune system and the remainder of the body, while supporting vectorial transport of nutrients, water and waste products. Epithelial barrier function requires a contiguous layer of cells as well as the junctions that seal the paracellular space between epithelial cells. Compromised intestinal barrier function has been associated with a number of disease states, both intestinal and systemic. Unfortunately, most current clinical data are correlative, making it difficult to separate cause from effect in interpreting the importance of barrier loss. Some data from experimental animal models suggest that compromised epithelial integrity might have a pathogenic role in specific gastrointestinal diseases, but no FDA-approved agents that target the epithelial barrier are presently available. To develop such therapies, a deeper understanding of both disease pathogenesis and mechanisms of barrier regulation must be reached. Here, we review and discuss mechanisms of intestinal barrier loss and the role of intestinal epithelial barrier function in pathogenesis of both intestinal and systemic diseases. We conclude with a discussion of potential strategies to restore the epithelial barrier.

The adaptor protein Cindr regulates JNK activity to maintain epithelial sheet integrity

Epithelia are essential barrier tissues that must be appropriately maintained for their correct function. To achieve this a plethora of protein interactions regulate epithelial cell number, structure and adhesion, and differentiation. Here we show that Cindr (the Drosophila Cin85 and Cd2ap ortholog) is required to maintain epithelial integrity. Reducing Cindr triggered cell delamination and movement. Most delaminating cells died. These behaviors were consistent with JNK activation previously associated with loss of epithelial integrity in response to ectopic oncogene activity. We confirmed a novel interaction between Cindr and Drosophila JNK (dJNK), which when perturbed caused inappropriate JNK signaling. Genetically reducing JNK signaling activity suppressed the effects of reducing Cindr. Furthermore, ectopic JNK signaling phenocopied loss of Cindr and was partially rescued by concomitant cindr over-expression. Thus, correct Cindr-dJNK stoichiometry is essential to maintain epithelial integrity and disturbing this balance may contribute to the pathogenesis of disease states, including cancer.

Par6G suppresses cell proliferation and is targeted by loss-of-function mutations in multiple cancers.

Differentiated epithelial structure communicates with individual constituent epithelial cells to suppress their proliferation activity. However, the pathways linking epithelial structure to cessation of the cell proliferation machinery or to unscheduled proliferation in the context of tumorigenesis are not well defined. Here we demonstrate the strong impact of compromised epithelial integrity on normal and oncogenic Myc-driven proliferation in three-dimensional mammary epithelial organoid culture. Systematic silencing of 34 human homologs of Drosophila genes, with previously established functions in control of epithelial integrity, demonstrates a role for human genes of apico-basal polarity, Wnt and Hippo pathways and actin dynamics in regulation of the size, integrity and cell proliferation in organoids. Perturbation of these pathways leads to diverse functional interactions with Myc: manifested as a RhoA-dependent synthetic lethality and Par6-dependent effects on the cell cycle. Furthermore, we show a role for Par6G as a negative regulator of the phosphatidylinositol 3′-kinase/phosphoinositide-dependent protein kinase 1/Akt pathway and epithelial cell proliferation and evidence for frequent inactivation of Par6G gene in epithelial cancers. The findings demonstrate that determinants of epithelial structure regulate the cell proliferation activity via conserved and cancer-relevant regulatory circuitries, which are important for epithelial cell cycle restriction and may provide new targets for therapeutic intervention.

Collagen VI Is Upregulated in COPD and Serves Both as an Adhesive Target and a Bactericidal Barrier for Moraxella catarrhalis

Moraxella catarrhalis is a Gram-negative human mucosal commensal and pathogen. It is a common cause of exacerbation in chronic obstructive pulmonary disease (COPD). During the process of infection, host colonization correlates with recognition of host molecular patterns. Importantly, in COPD patients with compromised epithelial integrity the underlying extracellular matrix is exposed and provides potential adhesive targets. Collagen VI is a ubiquitous fibrillar component in the airway mucosa and has been attributed both adhesive and killing properties against Gram-positive bacteria. However, less is known regarding Gram-negative microorganisms. Therefore, in the present study, the interaction of M. catarrhalis with collagen VI was characterized. We found that collagen VI is upregulated in the airways of COPD patients and exposed upon epithelial desquamation. Ex vivo, we inoculated airway biopsies and fibroblasts from COPD patients with M. catarrhalis. The bacteria specifically adhered to collagen VI-containing matrix fibrils. In vitro, purified collagen VI microfibrils bound to bacterial surface structures. The primary adhesion target was mapped to the collagen VI α₂-chain. Upon exposure to collagen VI, bacteria were killed by membrane destabilization in physiological conditions. These previously unknown properties of collagen VI provide novel insights into the extracellular matrix innate immunity by quickly entrapping and killing pathogen intruders.

Endometrial apical glycoproteomic analysis reveals roles for cadherin 6, desmoglein-2 and plexin b2 in epithelial integrity.

Implantation failure is one of the major causes of infertility and remains a major barrier to assisted reproduction success. Initial receptivity to implantation is regulated by the endometrial luminal epithelium under maternal hormonal control. Identification of epithelial cell surface components involved in embryo attachment will have translational applications in early pregnancy failure, infertility and contraception. In this study, vectorial biotinylation has been used to characterize the apical glycoproteome of Ishikawa cells, a polarized cell line that serves as a model of the implantation-receptive human endometrial luminal epithelium. Of 46 surface-associated glycoproteins detected by mass spectrometry, half are newly reported in this cell type; a subgroup of these were chosen for evaluation in tissue, and all were shown to be expressed apically in vivo in the mid-secretory (implantation) phase of the menstrual cycle, thus validating the model. Eleven adhesion molecules were detected, some already known to be involved in implantation, others novel. Cadherin 6, desmoglein 2 and plexin b2 were surprisingly found in the apical as well as the lateral membrane domain; their knock-down compromised epithelial integrity. This method of targeting glycosylated apical surface moieties in a polarized epithelial culture model shows excellent selectivity and identifies candidate cell adhesion molecules that are also present in vivo in secretory phase endometrial epithelium.

Oral epithelial cell reaction after exposure to Invisalign plastic material

Invisalign plastic aligners (Align Technology, Santa Clara, Calif) are used to correct malocclusions. The aligners wrap around the teeth and are in contact with gingival epithelium during treatment. The purpose of this study was to evaluate the cellular responses of oral epithelium exposed to Invisalign plastic invitro. Oral epithelial cells were exposed to eluate obtained by soaking Invisalign plastic in either saline solution or artificial saliva for 2, 4, and 8 weeks. Cells grown in media containing saline solution or saliva served as controls. Morphologic changes were assessed by light microscopy. The 3-[4, 5-dimethythiazol- 2-yl]-2, 5-diphenyl tetrazolium bromide assay and flow cytometry were used to determine cell viability and membrane integrity, respectively. Cellular adhesion and micromotion of epithelial cells were measured in real time by electrical cell-substrate impedance sensing. Cells exposed to saline-solution eluate appeared rounded, were lifted from the culture plates, and demonstrated significantly increased metabolic inactivity or cell death (P<0.05). Saliva eluates did not induce significant changes in cell viability compared with untreated cells. Flow cytometry and electric cell-substrate impedance sensing showed that cells treated with saline-solution eluate exhibited compromised membrane integrity, and reduced cell-to-cell contact and mobility when compared with saliva-eluate treatment. Exposure to Invisalign plastic caused changes in viability, membrane permeability, and adhesion of epithelial cells in a saline-solution environment. Microleakage and hapten formation secondary to compromised epithelial integrity might lead to isocyanate allergy, which could be systemic or localized to gingiva. However, these results suggest that saliva might offer protection.

Probability of Radiographic Radiation Pneumonitis (RP) and Fibrosis (RF) After Stereotactic Ablative Radiation Therapy (SABR) for Lung Cancer Using NTCP Model

Materials/Methods: Male C57/Bl6 mice eight weeks of age were pretreated with saline or 8 mg of the prolyl hydroxylase inhibitor DMOG 16 hrs and 4 hrs prior to being irradiated with a single fraction of 20 Gy to the abdomen using a modified TLI jig that shields the upper body of the mouse to reduce hematopoietic toxicity. After XRT, the mice got daily doses of saline or DMOG for 5 days. Results: Mice treated with DMOG had a 1.5-fold enrichment of crypt regeneration in the colon as determined by the classical microcolony assay (13.3 3.4 vs. 21.2 1.7 crypts/section, saline vs. DMOG, nZ 10/group, p Z 0.005), which strongly suggests that prolyl hydroxylase inhibition radioprotects the colon. Death from GI radiotoxicity can result from compromised epithelial integrity. Death from GI radiotoxicity can result from compromised epithelial integrity through reduced barrier function and water absorption leading to sepsis, dehydration and electrolyte imbalance. We tested epithelial and barrier function by gavaging irradiated mice with FITC-dextran, which should be undetectable in the blood unless the GI epithelia are compromised. Treatment with DMOG decreased FITC-dextran uptake by 4-fold over controls (52.6 14.7 vs. 12.4 3.4 mcg/mL, n Z 6/group, p Z 0.02). Using metabolic cage analysis, we find that mice treated with DMOG had more formed stools, increased urine output and less weight loss than saline treated mice. Mice treated with only saline had higher sodium and Cr levels, further suggesting that GI function and water balance is improved with DMOG treatment. These physiologic improvements translated to improved overall survival with DMOG treatment after being exposed to 20 Gy of abdominal radiation (p Z 0.01). In addition, mice treated with DMOG within 4 hours after radiation also showed improved survival, although with more mortality than if dosed before receiving radiation. Conclusions: Maintaining epithelial integrity should be a therapeutic goal in treating GI radiotoxicity. Physiologic measurements are an important adjunct to cellular and histologic methods of assessing radioprotection in the gut. Author Disclosure: C.M. Taniguchi: None. T. Atwood: None. A.J. Giaccia: None.

Intestinal HIF-2 to protect against radiation-induced gastrointestinal syndrome.

10629 Background: Gastrointestinal (GI) toxicity accounts for significant morbidity during systemic chemotherapy or abdominopelvic radiation therapy. Unfortunately, there are no effective preventative treatments. Hypoxic signaling through hypoxia-inducible factor-1 (HIF-1) and -2 (HIF-2) is critical for intestinal homeostasis during inflammatory challenges and was posited to play a role in radioprotection. Methods: We stabilized both HIF-1 and HIF-2 pharmacologically with the prolyl hydroxylase inhibitor DMOG and with transgenic mice. Male C57/Bl6 mice eight weeks of age were pretreated with saline or 8mg DMOG 16hrs and 4hrs prior to being irradiated with a single fraction of 20Gy to the abdomen using a modified TLI jig that shields the upper body of the mouse to reduce hematopoietic toxicity. After XRT, the mice got daily doses of saline or DMOG for 5 days. Results: Mice treated with DMOG had a 1.5-fold enrichment of crypt regeneration in the colon as determined by microcolony assay (13.3±3.4 vs 21.2±1.7 crypts/section, saline vs DMOG, n=10/group, p=0.005). Death from GI radiotoxicity can result from compromised epithelial integrity. We tested epithelial and barrier function by gavaging irradiated mice with FITC-dextran, which undetectable in the blood unless the GI epithelia is compromised. Treatment with DMOG decreased FITC-dextran uptake by 4-fold over controls (52.6±14.7 vs 12.4±3.4 mcg/ml, n=6/group, p=0.02). These physiologic improvements translated to improved overall survival with DMOG treatment after being exposed to 20Gy of abdominal radiation (p=0.03). To determine if the radioprotective effect of DMOG was specific to HIF-1 or HIF-2, we overexpressed stabilized HIF1 or HIF2 in the intestinal epithelia using a lox-stop-lox (LSL) system and Villin-Cre. The overexpression of HIF1 had no effect on survival (p=0.22), while mice with intestinal-specific HIF2-overexpression had significantly improved survival after receiving 20Gy of abdominal radiation (p=0.001). Conclusions: Activation of HIF-2 is sufficient to protect mice from lethal doses of abdominal radiation may provide a novel class of treatments to protect the GI epithelium from the deleterious side effects of chemotherapy and radiation.

A glycomimetic compound inhibits DC-SIGN-mediated HIV infection in cellular and cervical explant models

Dendritic cell-specific intercellular adhesion molecule (ICAM)-3 grabbing nonintegrin (DC-SIGN) participates in the initial stages of sexually transmitted HIV-1 infection by recognizing highly mannosylated structures presented in multiple copies on HIV-1 gp120 and promoting virus dissemination. Inhibition of HIV interaction with DC-SIGN thus represents a potential therapeutic approach for viral entry inhibition at the mucosal level. Herein we evaluate the efficacy in inhibiting HIV-1 infection and the potential toxicity of a multimeric glycomimetic DC-SIGN ligand (Dendron 12). The ability of Dendron 12 to block HIV-1 infection was assessed in cellular and human cervical explant models. Selectivity of Dendron 12 towards DC-SIGN and langerin was evaluated by surface plasmon resonance studies. β chemokine production following stimulation with Dendron 12 was also analyzed. Toxicity of the compound was evaluated in cellular and tissue models. Dendron 12 averted HIV-1 trans infection of CD4(+) T lymphocytes in presence of elevated viral loads and prevented HIV-1 infection of human cervical tissues, under conditions mimicking compromised epithelial integrity, by multiple clades of R5 and X4 tropic viruses. Treatment with Dendron 12 did not interfere with the activity of langerin and also significantly elicited the production of the β chemokines MIP-1α, MIP-1β and RANTES. Dendron 12 thus inhibits HIV-1 infection by competition with binding of HIV to DC-SIGN and stimulation of β-chemokine production. Dendron 12 represents a promising lead compound for the development of anti-HIV topical microbicides.

Microbial influences on epithelial integrity and immune function as a basis for inflammatory diseases

Certain autoimmune diseases as well as asthma have increased in recent decades, particularly in developed countries. The hygiene hypothesis has been the prevailing model to account for this increase; however, epidemiology studies also support the contribution of diet and obesity to inflammatory diseases. Diet affects the composition of the gut microbiota, and recent studies have identified various molecules and mechanisms that connect diet, the gut microbiota, and immune responses. Herein, we discuss the effects of microbial metabolites, such as short chain fatty acids, on epithelial integrity as well as immune cell function. We propose that dysbiosis contributes to compromised epithelial integrity and disrupted immune tolerance. In addition, dietary molecules affect the function of immune cells directly, particularly through lipid G-protein coupled receptors such as GPR43.

Rectal gonorrhoea as an independent risk factor for HIV infection in a cohort of homosexual men.

To determine whether certain sexually transmitted diseases are independent risk factors for HIV transmission in a cohort of homosexual men. Eligible cases were identified as those who had seroconverted between November 1982 and November 1990. Two persistently HIV-seronegative control participants were randomly selected for each case from all participants who remained seronegative in November 1990. For cases, risk factor data were taken from an index visit which was defined as the first seropositive visit, while for controls these data were obtained from a matched visit which occurred within two months of the index visit for the corresponding case. Mantel-Haenszel methods and logistic regression were used to compare differences in risk factors for seroconversion between cases and controls. A total of 125 cases and 250 controls were eligible for this study. Cases were significantly more likely to have had reported any gonorrhoea (17% versus 6%; OR = 2.94; 95% CI: 1.51-5.73) or syphilis (7% versus 2%; OR = 3.78; 95% CI: 1.33-10.79) than controls during the seroconversion period. Multivariate logistic regression revealed rectal gonorrhoea to be independently associated with risk of seroconversion (odds ratio = 3.18; p = 0.044), whereas urethral gonorrhoea (p = 0.479) and pharyngeal gonorrhoea (p = 0.434) were not after inclusion of rectal gonorrhoea. In addition, the following variables were also shown to exert an independent effect on seroconversion: frequency of anal intercourse, use of illicit drugs, number of male sexual partners, and lack of a post-secondary education. In this observational study, rectal gonorrhoea was found to be associated with HIV seroconversion after adjustment for a number of HIV risk factors. We cannot rule out that rectal gonorrhoea was not directly associated with HIV infection but rather with other residual lifestyle factors not fully adjusted for in the analysis. However, the relationship with gonococcal involvement of a specific anatomic site lends support to a biological association between gonorrhoea and HIV infection, rather than to alternative non-biologic explanations. Our findings are consistent with previous studies reporting an association between HIV infection and non-ulcerative sexually transmitted diseases. Such a direct association might be explained by postulating that gonorrhoea results in inflamed rectal mucosa and compromised epithelial integrity, thereby predisposing an individual to subsequent HIV infection.

Turner's syndrome patients lack tight junctions between uterine epithelial cells

Eleven endometrial biopsies, taken from six Turner's syndrome patients receiving hormone replacement therapy prior to treatment by oocyte donation and embryo transfer, were assessed by freeze fracture followed by electron microscopy for epithelial tight junctions. Nine of the eleven biopsies had no discernible tight junctions; the other two biopsies had reduced and disorganized junctional structures. Two patients subsequently became pregnant following embryo transfer. It is concluded that compromised epithelial integrity does not prevent embryo implantation in the human, an observation that is consistent with a barrier role for the epithelium except at times when appropriately conditioned with oestrogen and progesterone to induce receptivity for implantation.