Cereblon regulates the production of hepatic fibroblast growth factor 23 in diabetes.

Cereblon (CRBN) is an extensively expressed protein involved in crucial physiological processes. This study reveals CRBN's role in governing hepatic fibroblast growth factor 23 (FGF23) expression and production via the cyclic adenosine monophosphate (cAMP) pathway in diabetic conditions. The expression of hepatic Crbn, Yin Yang 1 (Yy1), and Fgf23 genes were significantly increased in diabetic mice and forskolin (FSK)-treated primary hepatocytes, correlating with elevated FGF23 production. Overexpression of Crbn and Yy1 increased hepatic FGF23 and cytokines by upregulating YY1 gene expression, which was reduced in Crbn- and Yy1-silenced mice and primary hepatocytes. Besides, we found that CRBN-mediated regulation of hepatic FGF23 involved YY1 recruitment to the Fgf23 gene promoters, evidenced by reporter assays, deletion studies, and mutant analyses. These findings identify CRBN and YY1 as key contributors to gluconeogenic signaling-driven FGF23 production and inflammation in diabetes, highlighting their potential as therapeutic targets for addressing metabolic disorders like diabetes.

Enhancement of the SESN2-SHP cascade by melatonin ameliorates hepatic gluconeogenesis by inhibiting the CRBN-BTG2-CREBH signaling pathway.

Melatonin is involved in the regulation of various biological functions. Here, we explored a novel molecular mechanism by which the melatonin-induced sestrin2 (SESN2)-small heterodimer partner (SHP) signaling pathway protects against fasting- and diabetes-mediated hepatic glucose metabolism. Various key gene expression analyses were performed and multiple metabolic changes were assessed in liver specimens and primary hepatocytes of mice and human participants. The expression of the hepatic cereblon (CRBN) and b-cell translocation gene 2 (BTG2) genes was significantly increased in fasting mice, diabetic mice, and patients with diabetes. Overexpression of Crbn and Btg2 increased hepatic gluconeogenesis by enhancing cyclic adenosine monophosphate (cAMP)-responsive element-binding protein H (CREBH), whereas this phenomenon was prominently ablated in Crbn null mice and Btg2-silenced mice. Interestingly, melatonin-induced SESN2 and SHP markedly reduced hepatic glucose metabolism in diabetic mice and primary hepatocytes, and this protective effect of melatonin was strikingly reversed by silencing Sesn2 and Shp. Finally, the melatonin-induced SESN2-SHP signaling pathway inhibited CRBN- and BTG2-mediated hepatic gluconeogenic gene transcription via the competition of BTG2 and the interaction of CREBH. Mitigation of the CRBN-BTG2-CREBH axis by the melatonin-SESN2-SHP signaling network may provide a novel therapeutic strategy to treat metabolic dysfunction due to diabetes.

Mustard Gas-Induced Ocular Surface Disorders: An Update on the Pathogenesis, Clinical Manifestations, and Management.

PURPOSE: Mustard gas (MG) is a potent blistering and alkylating agent that has been used for military and terrorism purposes. Ocular surface injuries are common after exposure to MG. This review provides an update on the pathophysiology, ocular surface complications, and treatment options for MG-related ocular injuries. METHODS: Required information was obtained by reviewing various databases such as Cochrane Library, Google Scholar, and PubMed until March 2022. Data were collected by using keywords: "mustard gas" OR "sulfur mustard" AND "eye" OR "cornea" OR "ocular complication" OR "keratitis" OR "keratopathy" OR "limbal stem cell deficiency" OR "dry eye." RESULTS: Chronic intracellular toxicity, inflammation, and ischemia have been shown to play an essential role in the pathogenesis of MG injury. Ocular surface injuries can have acute, chronic, and most distinctly a delayed-onset presentation leading to various degrees of limbal stem cell deficiency. To date, no treatment has been agreed on as the standard treatment for chronic/delayed-onset MG keratopathy. Based on the authors' experience, we propose a management algorithm for MG-related ocular surface injuries involving optimization of ocular health, anti-inflammatory therapy, and if needed surgical interventions. The management of chronic and delayed-onset presentation remains challenging. CONCLUSIONS: MG keratopathy is a unique form of chemical injury which can lead to a range of ocular surface pathologies. Long-term anti-inflammatory therapy even in patients with seemingly mild disease may potentially reduce the likelihood of the development of more severe delayed-onset disease.

Therapeutic Potential of Mesenchymal Stem Cell-Secreted Factors on Delay in Corneal Wound Healing by Nitrogen Mustard.

Ocular surface exposure to nitrogen mustard (NM) leads to severe ocular toxicity which includes the separation of epithelial and stromal layers, loss of endothelial cells, cell death, and severe loss of tissue function. No definitive treatment for mustard gas-induced ocular surface disorders is currently available. The research was conducted to investigate the therapeutic potential of mesenchymal stem cell-conditioned media (MSC-CM) in NM-induced corneal wounds. NM was added to different types of corneal cells, the ocular surface of porcine, and the ocular surface of mice, followed by MSC-CM treatment. NM significantly induced apoptotic cell death, cellular ROS (Reactive oxygen species), and reduced cell viability, metabolic gene expression, and mitochondrial function, and, in turn, delayed wound healing. The application of MSC-CM post NM exposure partially restored mitochondrial function and decreased intracellular ROS generation which promoted cell survival. MSC-CM therapy enhanced wound healing process. MSC-CM inhibited NM-induced apoptotic cell death in murine and porcine corneal tissue. The application of MSC-CM following a chemical insult led to significant improvements in the preservation of corneal structure and wound healing. In vitro, ex vivo, and in vivo results suggest that MSC-CM can potentially provide targeted therapy for the treatment of chemical eye injuries, including mustard gas keratopathy (MGK) which presents with significant loss of vision alongside numerous corneal pathologies.

Growth hormone promotes hepatic gluconeogenesis by enhancing BTG2-YY1 signaling pathway.

Growth hormone (GH) is one of the critical factors in maintaining glucose metabolism. B-cell translocation gene 2 (BTG2) and yin yang 1 (YY1) are key regulators of diverse metabolic processes. In this study, we investigated the link between GH and BTG2-YY1 signaling pathway in glucose metabolism. GH treatment elevated the expression of hepatic Btg2 and Yy1 in primary mouse hepatocytes and mouse livers. Glucose production in primary mouse hepatocytes and serum blood glucose levels were increased during GH exposure. Overexpression of hepatic Btg2 and Yy1 induced key gluconeogenic enzymes phosphoenolpyruvate carboxykinase 1 (PCK1) and glucose-6 phosphatase (G6PC) as well as glucose production in primary mouse hepatocytes, whereas this phenomenon was markedly diminished by knockdown of Btg2 and Yy1. Here, we identified the YY1-binding site on the Pck1 and G6pc gene promoters using reporter assays and point mutation analysis. The regulation of hepatic gluconeogenic genes induced by GH treatment was clearly linked with YY1 recruitment on gluconeogenic gene promoters. Overall, this study demonstrates that BTG2 and YY1 are novel regulators of GH-dependent regulation of hepatic gluconeogenic genes and glucose production. BTG2 and YY1 may be crucial therapeutic targets to intervene in metabolic dysfunction in response to the GH-dependent signaling pathway.

Corneal nerve healing after in situ laser nerve transection.

PURPOSE: We have previously reported that lamellar dissection of the cornea transects stromal nerves, and that regenerating neurites form a dense net along the surgical plane. In these experiments, we have disrupted the stromal nerve trunks in situ, without incising the cornea, to determine the regeneration events in the absence of a surgical plane. METHODS: Thy1-YFP mice were anesthetized and in vivo images of the corneal nerves were obtained with a wide-field stereofluorescent microscope. A far infrared XYRCOS Laser attached to 20X objective of an upright microscope was used to perform in situ transection of the stromal nerves. 3 types of laser transections were performed (n = 5/group): (i) point transection (a single cut); (ii) segmental transection (two cuts enclosing a segment of nerve trunk); and (iii) annular transection (cuts on all nerve trunks crossing the perimeter of a 0.8 mm diameter circular area centered on the corneal apex). Mice were imaged sequentially for 4 weeks thereafter to assess nerve degeneration (disappearance or weakening of original fluorescence intensity) or regeneration (appearance of new fluorescent fronds). Beta-3-tubulin immunostaining was performed on corneal whole-mounts to demonstrate nerve disruption. RESULTS: The pattern of stromal nerves in corneas of the same mouse and in corneas of littermates was dissimilar. Two distinct patterns were observed, often within the same cornea: (i) interconnected trunks that spanned limbus to limbus; or (ii) dichotomously branching trunks that terminate at the corneal apex. Point transections did not cause degeneration of proximal or distal segment in interconnected trunks, but resulted in degeneration of distal segment of branching trunks. In segmental transections, the nerve segment enclosed within the two laser cuts degenerated. Lack of beta-3 tubulin staining at transection site confirmed nerve transection. In interconnected trunks, at 4 weeks, a hyperfluorescent plaque filled the gap created by the transection. In annular transections, some nerve trunks degenerated, while others regained or retained fluorescence. CONCLUSIONS: Interconnected stromal nerves in murine corneas do not degenerate after in situ point transection and show evidence of healing at the site of disruption. Presence or absence of a surgical plane influences corneal nerve regeneration after transection.

Safety and efficacy of radiological percutaneous jejunostomy for decompression of malignant small bowel obstruction.

OBJECTIVES: This study aimed to evaluate the safety and efficacy of percutaneous radiological jejunostomy (PRJ) and stent placement in patients with malignant small bowel obstructions (MSBO). METHODS: A total of 21 patients (mean age 60 years) with single (n = 4) or multiple (n = 17) MSBO underwent PRJ following jejunopexy. The medical records and imaging studies were retrospectively reviewed to evaluate the technical/clinical success and complications. Clinical success was determined by symptomatic relief and radiologic bowel decompression. RESULTS: PRJ using a 12- or 14-F drainage catheter was technically successful in all patients. Eleven patients required placement of an 18-F nasogastric tube across one (n = 3), two (n = 6) and three (n = 2) obstructions to achieve clinical success. Subsequently, self-expandable stents were placed through the PRJ tracts to recanalise MSBO in four patients. Clinical success was achieved in 18 patients (85.7 %). The median food intake capacity score improved from 4.0 to 2.0 (P = 0.001). There were one major (peritonitis, 4.8 %) and six minor complications (28.6 %) CONCLUSIONS: PRJ using a nasogastric tube across the obstructions is an effective palliative treatment for MSBO. The PRJ tract can be used as an approach route for stent placement to recanalise MSBO. However, dedicated devices should be developed to reduce frequent procedure-related complications. KEY POINTS: • Bowel decompression provides palliative treatment in malignant small bowel obstruction • Percutaneous radiological jejunostomy (PRJ) is a safe and effective palliative treatment. • Long tube placement across obstructions facilitates adequate drainage of multiple bowel obstructions. • PRJ tract can be used for stent placement to approach MSBO recanalisation.