Deletion of TXNIP Mitigates High-Fat Diet-Impaired Angiogenesis and Prevents Inflammation in a Mouse Model of Critical Limb Ischemia

Abstract

Background: Previous work demonstrated that high-fat diet (HFD) triggered thioredoxin-interacting protein (TXNIP) and that silencing TXNIP prevents diabetes-impaired vascular recovery. Here, we examine the impact of genetic deletion of TXNIP on HFD-impaired vascular recovery using hind limb ischemia model. Methods: Wild type mice (WT, C57Bl/6) and TXNIP knockout mice (TKO) were fed either normal chow diet (WT-ND and TKO-ND) or 60% high-fat diet (WT-HFD and TKO-HFD). After four weeks of HFD, unilateral hind limb ischemia was performed and blood flow was measured using Laser doppler scanner at baseline and then weekly for an additional three weeks. Vascular density, nitrative stress, infiltration of CD68+ macrophages, and expression of inflammasome, vascular endothelial growth factor (VEGF), VEGF receptor-2 were examined by slot blot, Western blot and immunohistochemistry. Results: By week 8, HFD caused similar increases in weight, cholesterol and triglycerides in both WT and TKO. At week 4 and week 8, HFD significantly impaired glucose tolerance in WT and to a lesser extent in TKO. HFD significantly impaired blood flow and vascular density (CD31 labeled) in skeletal muscle of WT mice compared to ND but not in TKO. HFD and ischemia significantly induced tyrosine nitration, and systemic IL-1β and infiltration of CD68+ cells in skeletal muscle from WT but not from TKO. HFD significantly increased cleaved-caspase-1 and IL-1 β compared to ND. Under both ND, ischemia tended to increase VEGF expression and increased VEGFR2 activation in WT only but not TKO. Conclusion: Similar to prior observation in diabetes, HFD-induced obesity can compromise vascular recovery in response to ischemic insult. The mechanism involves increased TXNIP-NLRP3 (nucleotide-binding oligomerization domain-like receptor protein 3) inflammasome activation, nitrative stress and impaired VEGFR2 activation. Deletion of TXNIP restored blood flow, reduced nitrative stress and blunted inflammasome-mediated inflammation; however, it did not impact VEGF/VEGFR2 in HFD. Targeting TXNIP-NLRP3 inflammasome can provide potential therapeutic target in obesity-induced vascular complication.

Exosomes Derived From Mesenchymal Stromal Cells Pretreated With Advanced Glycation End Product-Bovine Serum Albumin Inhibit Calcification of Vascular Smooth Muscle Cells

“…Increased expression of TXNIP and reduced Trx activity have been observed in animal models of diabetes. TXNIP is a key factor in the regulation of functional β-cell mass, and inhibition of TXNIP ameliorates the symptoms of diabetes ( 40 ); for example, knockdown of TXNIP ameliorated high-glucose-induced epithelial—to—mesenchymal transition in renal tubular epithelial cells ( 60 ) and deletion of TXNIP prevented high-fat-diet-induced inflammation in critical-limb ischemic mice ( 61 ). In addition, the diabetic lipid environment can induce TXNIP expression, which stimulates the vascular inflammation ( 61 ).…”

TXNIP/TBP-2: A Master Regulator for Glucose Homeostasis

“…TXNIP deficiency impaired the activation of the NLRP3 inflammasome and the subsequent secretion of interleukin-1β (IL-1β) in macrophages. Although TXNIP-NLRP3 inflammasome axis is independent with known NLRP3 activation by oligomers of islet amyloid polypeptides (IAPP) [ 49 ] (a protein that forms amyloid deposits that has been observed during type-2 diabetes in pancreatic β cells), TXNIP-NLRP3 inflammasome axis seems to be an important regulator for specific tissue inflammation in redox dependent and independent manners [ 48 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 , 71 ].…”

Deletion of Thioredoxin-Interacting Protein (TXNIP) Abrogates High Fat Diet-Induced Retinal Leukostasis, Barrier Dysfunction and Microvascular Degeneration in a Mouse Obesity Model

“…Isolated PBMCs from WT-HFD mice but not TKO-HFD mice resulted in increased leukostasis and apoptosis (p = 0.07 compared with WT-ND) of mouse retinal EC cultures, after 2 and 24 h in co-culture, respectively. Our recent studies using the HFD model showed significant increases in IL-1β serum level that was mitigated by genetic deletion of TXNIP [26]. Together, these results highlight a potential role for circulating leukocytes in mediating EC death in models of HFD via both direct and indirect EC death pathways.…”

“…Fasting blood glucose levels were recorded at 8, 12 and 18 weeks, and HFD induced a modest yet significant increase in fasting blood glucose levels in WT-HFD when compared with the WT-ND group at 8 weeks through 18 weeks of study (* p < 0.05, n = 11-19, Table 1). TKO mice showed lower blood glucose levels and were partially protected against HFD-induced insulin resistance observed in WT-HFD mice as described before [26]. Table 1.…”

“…Activated NLRP3 oligomerizes with the ASC (apoptosis-associated speck-like) adaptor protein which recruits procaspase-1, allowing its autocleavage and activation, which in turn cleaves IL-1β into active mature form before its release [19,25]. Our group previously demonstrated that TXNIP is required for the activation of the upstream signaling complex, the NLRP3-inflammasome and resulting inflammation in liver and skeletal muscle from HFD-fed mice [20,26]. Here, we examined the impact of HFD as well as TXNIP deletion on retinal leukostasis, barrier dysfunction and microvascular degeneration in vivo.…”