Novel Immunomodulatory Cytokine Regulates Inflammation, Diabetes, and Obesity to Protect From Diabetic Nephropathy

Obesity-linked (type 2) diabetic nephropathy (T2DN) has become the largest contributor to morbidity and mortality in the modern world. Recent evidences suggest that inflammation may contribute to the pathogenesis of T2DN and T-regulatory cells (Treg) are protective. We developed a novel cytokine (named IL233) bearing IL-2 and IL-33 activities in a single molecule and demonstrated that IL233 promotes Treg and T-helper (Th) 2 immune responses to protect mice from inflammatory acute kidney injury. Here, we investigated whether through a similar enhancement of Treg and inhibition of inflammation, IL233 protects from T2DN in a genetically obese mouse model, when administered either early or late after the onset of diabetes. In the older mice with obesity and microalbuminuria, IL233 treatment reduced hyperglycemia, plasma glycated proteins, and albuminuria. Interestingly, IL233 administered before the onset of microalbuminuria not only strongly inhibited the progression of T2DN and reversed diabetes as indicated by lowering of blood glucose, normalization of glucose tolerance and insulin levels in islets, but surprisingly, also attenuated weight gain and adipogenicity despite comparable food intake. Histological examination of kidneys showed that saline control mice had severe inflammation, glomerular hypertrophy, and mesangial expansion, which were all attenuated in the IL233 treated mice. The protection correlated with greater accumulation of Tregs, group 2 innate lymphoid cells (ILC2), alternately activated macrophages and eosinophils in the adipose tissue, along with a skewing toward T-helper 2 responses. Thus, the novel IL233 cytokine bears therapeutic potential as it protects genetically obese mice from T2DN by regulating multiple contributors to pathogenesis.Short Description: A novel bifunctional cytokine IL233, bearing IL-2 and IL-33 activities reverses inflammation and protects from type-2 diabetic nephropathy through promoting T-regulatory cells and type 2 immune response

Pannexin 1 channels facilitate communication between T cells to restrict the severity of airway inflammation

Allergic airway inflammation is driven by type-2 CD4(+) T cell inflammatory responses. We uncover an immunoregulatory role for the nucleotide release channel, Panx1, in T cell crosstalk during airway disease. Inverse correlations between Panx1 and asthmatics and our mouse models revealed the necessity, specificity, and sufficiency of Panx1 in T cells to restrict inflammation. Global Panx1(-/-) mice experienced exacerbated airway inflammation, and T-cell-specific deletion phenocopied Panx1(-/-) mice. A transgenic designed to re-express Panx1 in T cells reversed disease severity in global Panx1(-/-) mice. Panx1 activation occurred in pro-inflammatory T effector (Teff) and inhibitory T regulatory (Treg) cells and mediated the extracellular-nucleotide-based Treg-Teff crosstalk required for suppression of Teff cell proliferation. Mechanistic studies identified a Salt-inducible kinase-dependent phosphorylation of Panx1 serine 205 important for channel activation. A genetically targeted mouse expressing non-phosphorylatable Panx1S205A phenocopied the exacerbated inflammation in Panx1(-/-) mice. These data identify Panx1-dependent Treg:Teff cell communication in restricting airway disease

Phagocytosis in the retina promotes local insulin production in the eye

The retina is highly metabolically active, relying on glucose uptake and aerobic glycolysis. Situated in close contact to photoreceptors, a key function of cells in the retinal pigment epithelium (RPE) is phagocytosis of damaged photoreceptor outer segments (POS). Here we identify RPE as a local source of insulin in the eye that is stimulated by POS phagocytosis. We show that Ins2 messenger RNA and insulin protein are produced by RPE cells and that this production correlates with RPE phagocytosis of POS. Genetic deletion of phagocytic receptors (‘loss of function’) reduces Ins2, whereas increasing the levels of the phagocytic receptor MerTK (‘gain of function’) increases Ins2 production in male mice. Contrary to pancreas-derived systemic insulin, RPE-derived local insulin is stimulated during starvation, which also increases RPE phagocytosis. Global or RPE-specific Ins2 gene deletion decreases retinal glucose uptake in starved male mice, dysregulates retinal physiology, causes defects in phototransduction and exacerbates photoreceptor loss in a mouse model of retinitis pigmentosa. Collectively, these data identify RPE cells as a phagocytosis-induced local source of insulin in the retina, with the potential to influence retinal physiology and disease

Renal regeneration after acute kidney injury.

Acute kidney injury is common and associated with negative renal and patient outcomes. The human kidney has a real but limited regeneration capacity. Understanding renal regeneration may allow us to manipulate this process and thus develop therapeutic weapons to improve patients' outcome. In the first part of this paper we discuss the clinical factors associated with renal recovery: baseline patient particularities, acute kidney injury characteristics and the medical approach taken in the short and long-term. In the second part, the cellular and molecular mechanisms underlying renal regeneration are explored. The immune system seems to have an important role, first promoting inflammation and then tissue healing. Other players, such as cellular senescence, mitochondrial dysfunction, renal haemodynamics and metabolic reprogramming also have a role in renal regeneration. We aim to develop a short review of renal regeneration, offering a holistic view of this process.info:eu-repo/semantics/publishedVersio