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Infections are common in patients with diabetes. Moreover, increasing incidence of antibiotic resistance impedes the complete bacterial clearance and calls for alternative treatment strategies. Along with antibacterial resistance, compromised host conditions create a favorable condition for the disease progression. In particular, cell junction proteins are of major importance as they contribute to a tight cell barrier, protecting against invading pathogens. However, the impact of high glucose on cell junction proteins has received little attention in the urinary bladder but merits closer investigation. Here, we report that during diabetes the expression of cell junction protein, claudin 14 is compromised in the human urine exfoliated cells and in the urinary bladder of type 2 diabetic mouse. Further in vitro analysis confirmed a direct correlation of lower intracellular calcium levels with claudin 14 expression in high glucose-treated human uroepithelial cells. Moreover, external calcium supplementation in high glucose-treated cells significantly affected the cell migration and restored the claudin 14 expression through focal adhesion and β-1 integrins. Strengthening the epithelial barrier is essential, especially in individuals with diabetes where basal calcium levels could contribute. [ABSTRACT FROM AUTHOR]

The development of in vitro hepatocyte cell culture systems is crucial for investigating drug-induced liver injury (DILI). One prerequisite for monitoring DILI related immunologic reactions is the extension of primary human hepatocyte (PHH) cultures towards the inclusion of macrophages. Therefore, we developed and characterized an autologous co-culture system of PHH and primary human hepatic macrophages (hepM) (CoC1). We compared CoC1 with a co-culture of the same PHH batch + M0 macrophages derived from THP1 cells (CoC2) in order to represent a donor independent macrophage reaction. Then, we treated the mono- and co-cultures with drugs that cause DILI—menadione (MEN, 1 or 10 µM, 3 h), diclofenac (DIC, 0.5 or 5 mM, 6 h), or acetaminophen (APAP, 0.5 or 5 mM, 6 h)—and assessed culture stability, cell activity, macrophage differentiation, cytokine production and cell viability. Without drug treatment, CoC1 was the most stable over a culture time of up to 60 h. Cytokine array analysis revealed a proinflammatory profile of PHH mono-cultures due to isolation stress but showed different influences of hepM and M0 on the cytokine profile in the co-cultures. MEN, DIC and APAP treatment led to donor-dependent signs of cell stress and toxicity. HepM can either promote or reduce the DILI effects donor dependently in CoC1. CoC2 are slightly less sensitive than CoC1 in representing DILI. In summary, we present a new autologous co-culture system that can mimic DILI in a donor-dependent manner. This cellular system could be useful for new drug testing strategies and reducing animal testing. [ABSTRACT FROM AUTHOR]

Diabetes is known to increase susceptibility to infections, partly due to impaired granulocyte function and changes in the innate immunity. Here, we investigate the effect of diabetes, and high glucose on the expression of the antimicrobial peptide, psoriasin and the putative consequences for E. coli urinary tract infection. Blood, urine, and urine exfoliated cells from patients are studied. The influence of glucose and insulin is examined during hyperglycemic clamps in individuals with prediabetes and in euglycemic hyperinsulinemic clamped patients with type 1 diabetes. Important findings are confirmed in vivo in type 2 diabetic mice and verified in human uroepithelial cell lines. High glucose concentrations induce lower psoriasin levels and impair epithelial barrier function together with altering cell membrane proteins and cytoskeletal elements, resulting in increasing bacterial burden. Estradiol treatment restores the cellular function with increasing psoriasin and bacterial killing in uroepithelial cells, confirming its importance during urinary tract infection in hyperglycemia. In conclusion, our findings present the effects and underlying mechanisms of high glucose compromising innate immunity. Patients with diabetes have an increased susceptibility to infections. Here the authors show that high glucose impairs innate immunity through reduced levels of the antimicrobial peptide psoriasin and impaired epithelial barrier function, resulting in an increased risk of urinary tract infection. [ABSTRACT FROM AUTHOR]

Urinary tract infection frequently caused by E. coli is one of the most common bacterial infections. Increasing antibiotic resistance jeopardizes successful treatment and alternative treatment strategies are therefore mandatory. Metformin, an oral antidiabetic drug, has been shown to activate macrophages in the protection against certain infecting microorganisms. Since epithelial cells often form the first line of defense, we here investigated the effect on uroepithelial cells during E. coli infection. Metformin upregulated the human antimicrobial peptides cathelicidin LL-37 and RNase7 via modulation of the TRPA1 channel and AMPK pathway. Interestingly, metformin stimulation enriched both LL-37 and TRPA1 in lysosomes. In addition, metformin specifically increased nitric oxide and mitochondrial, but not cytosolic ROS. Moreover, metformin also triggered mRNA expression of the proinflammatory cytokines IL1B, CXCL8 and growth factor GDF15 in human uroepithelial cells. The GDF15 peptide stimulated macrophages increased LL-37 expression, with increased bacterial killing. In conclusion, metformin stimulation strengthened the innate immunity of uroepithelial cells inducing enhanced extracellular and intracellular bacterial killing suggesting a favorable role of metformin in the host defense. [ABSTRACT FROM AUTHOR]