Probes for INS

Injection of herpes simplex virus vectors into the vitreous of primate eyes induces an acute, transient uveitis. The purpose of this study was to characterize innate immune responses of macaque neural retina tissue to the herpes simplex virus type 1-based gene delivery vector hrR3. PCR array analysis demonstrated the induction of the pro-inflammatory cytokine IL-6, as well as the anti-inflammatory cytokine IL-10, following hrR3 exposure. Secretion of IL-6 was detected by ELISA and cone photoreceptors and Muller cells were the predominant IL-6 positive cell types. RNA in situ hybridization confirmed that IL-6 was expressed in photoreceptor and Muller cells. The IL-10 positive cells in the inner nuclear layer were identified as amacrine cells by immunofluorescence staining with calretinin antibody. hrR3 challenge resulted in activation of NFκB (p65) in Muller glial cells, but not in cone photoreceptors, suggesting a novel regulatory mechanism for IL-6 expression in cone cells. hrR3 replication was not required for IL-6 induction or NFκB (p65) activation. These data suggest a pro-inflammatory (IL-6)/anti-inflammatory (IL-10) axis exists in neural retina and the severity of acute posterior uveitis may be determined by this interaction. Further studies are needed to identify the trigger for IL-6 and IL-10 induction and the mechanism of IL-6 induction in cone cells.

The cytokine interleukin-1β (IL-1β) is known to stimulate proinflammatory immune responses and impair β-cell function and viability, all critical events in the pathogenesis of type 1 diabetes (T1D). Here we evaluate the effect of SER140, a small peptide IL-1β receptor antagonist, on diabetes progression and cellular pancreatic changes in female nonobese diabetic (NOD) mice. Eight weeks of treatment with SER140 reduced the incidence of diabetes by more than 50% compared with vehicle, decreased blood glucose, and increased plasma insulin. Additionally, SER140 changed the endocrine and immune cells dynamics in the NOD mouse pancreas. Together, the data suggest that SER140 treatment postpones the onset of diabetes in female NOD mice by interfering with IL-1β activated pathways.

Abstract

BACKGROUND:

Mutation of HNF1B, the gene encoding transcription factor HNF-1β, is one cause of autosomal dominant tubulointerstitial kidney disease, a syndrome characterized by tubular cysts, renal fibrosis, and progressive decline in renal function. HNF-1β has also been implicated in epithelial-mesenchymal transition (EMT) pathways, and sustained EMT is associated with tissue fibrosis. The mechanism whereby mutated HNF1B leads to tubulointerstitial fibrosis is not known.

METHODS:

To explore the mechanism of fibrosis, we created HNF-1β-deficient mIMCD3 renal epithelial cells, used RNA-sequencing analysis to reveal differentially expressed genes in wild-type and HNF-1β-deficient mIMCD3 cells, and performed cell lineage analysis in HNF-1β mutant mice.

RESULTS:

The HNF-1β-deficient cells exhibited properties characteristic of mesenchymal cells such as fibroblasts, including spindle-shaped morphology, loss of contact inhibition, and increased cell migration. These cells also showed upregulation of fibrosis and EMT pathways, including upregulation of Twist2, Snail1, Snail2, and Zeb2, which are key EMT transcription factors. Mechanistically, HNF-1β directly represses Twist2, and ablation of Twist2 partially rescued the fibroblastic phenotype of HNF-1β mutant cells. Kidneys from HNF-1β mutant mice showed increased expression of Twist2 and its downstream target Snai2. Cell lineage analysis indicated that HNF-1β mutant epithelial cells do not transdifferentiate into kidney myofibroblasts. Rather, HNF-1β mutant epithelial cells secrete high levels of TGF-β ligands that activate downstream Smad transcription factors in renal interstitial cells.

CONCLUSIONS:

Ablation of HNF-1β in renal epithelial cells leads to the activation of a Twist2-dependent transcriptional network that induces EMT and aberrant TGF-β signaling, resulting in renal fibrosis through a cell-nonautonomous mechanism.