McClung Joseph M, McCord Timothy J, Ryan Terence E, Schmidt Cameron A, Green Tom D, Southerland Kevin W, Reinardy Jessica L, Mueller Sarah B, Venkatraman Talaignair N, Lascola Christopher D, Keum Sehoon, Marchuk Douglas A, Spangenburg Espen E, Dokun Ayotunde, Annex Brian H, Kontos Christopher D
From Department of Physiology and Diabetes and Obesity Institute, East Carolina University, Brody School of Medicine, Greenville, NC (J.M.M., T.E.R., C.A.S., T.D.G., E.E.S); Department of Medicine, Division of Cardiology (T.J.M., J.L.R., S.B.M., C.D.K.), Department of Surgery, Division of General Surgery (K.W.S.), Department of Pharmacology and Cancer Biology (J.L.R., S.B.M., C.D.K.), Department of Radiology (T.N.V., C.D.L.), and Department of Molecular Genetics and Microbiology (S.K., D.A.M.), Duke University Medical Center, Durham, NC; and Department of Medicine, Division of Endocrinology (A.D., B.H.A.), Division of Cardiovascular Medicine (B.H.A.), and Robert M. Berne Cardiovascular Research Center (B.H.A.), University of Virginia School of Medicine, Charlottesville.
Circulation. 2017 Jul 18;136(3):281-296. doi: 10.1161/CIRCULATIONAHA.116.024873. Epub 2017 Apr 25.
Critical limb ischemia is a manifestation of peripheral artery disease that carries significant mortality and morbidity risk in humans, although its genetic determinants remain largely unknown. We previously discovered 2 overlapping quantitative trait loci in mice, and , that affected limb muscle survival and stroke volume after femoral artery or middle cerebral artery ligation, respectively. Here, we report that a variant (Ile81Met) segregates with tissue protection from hind-limb ischemia.
We treated mice with either adeno-associated viruses encoding a control (green fluorescent protein) or 2 BAG3 (Bcl-2-associated athanogene-3) variants, namely Met81 or Ile81, and subjected the mice to hind-limb ischemia.
We found that the BAG3 Ile81Met variant in the C57BL/6 (BL6) mouse background segregates with protection from tissue necrosis in a shorter congenic fragment of (C.B6-). BALB/c mice treated with adeno-associated virus encoding the BL6 BAG3 variant (Ile81; n=25) displayed reduced limb-tissue necrosis and increased limb tissue perfusion compared with Met81- (n=25) or green fluorescent protein- (n=29) expressing animals. BAG3, but not BAG3, improved ischemic muscle myopathy and muscle precursor cell differentiation and improved muscle regeneration in a separate, toxin-induced model of injury. Systemic injection of adeno-associated virus-BAG3 (n=9), but not BAG3 (n=10) or green fluorescent protein (n=5), improved ischemic limb blood flow and limb muscle histology and restored muscle function (force production). Compared with BAG3, BAG3 displayed improved binding to the small heat shock protein (HspB8) in ischemic skeletal muscle cells and enhanced ischemic muscle autophagic flux.
Taken together, our data demonstrate that genetic variation in BAG3 plays an important role in the prevention of ischemic tissue necrosis. These results highlight a pathway that preserves tissue survival and muscle function in the setting of ischemia.
严重肢体缺血是外周动脉疾病的一种表现，在人类中具有显著的死亡和发病风险，尽管其遗传决定因素在很大程度上仍不清楚。我们之前在小鼠中发现了两个重叠的数量性状基因座，分别为 和 ，它们分别影响股动脉或大脑中动脉结扎后的肢体肌肉存活和心输出量。在此，我们报告一个 变体（Ile81Met）与后肢缺血的组织保护相关。
我们用编码对照（绿色荧光蛋白）或两种BAG3（Bcl-2相关抗凋亡基因-3）变体（即Met81或Ile81）的腺相关病毒处理小鼠，并使小鼠遭受后肢缺血。
我们发现C57BL/6（BL6）小鼠背景中的BAG3 Ile81Met变体在较短的同源片段 （C.B6-）中与组织坏死的保护相关。与表达Met81（n = 25）或绿色荧光蛋白（n = 29）的动物相比，用编码BL6 BAG3变体（Ile81；n = 25）的腺相关病毒处理的BALB/c小鼠显示肢体组织坏死减少，肢体组织灌注增加。在另一种毒素诱导的损伤模型中，BAG3而非BAG3改善了缺血性肌肉病变和肌肉前体细胞分化，并改善了肌肉再生。全身注射腺相关病毒-BAG3（n = 9）而非BAG3（n = 10）或绿色荧光蛋白（n = 5）改善了缺血肢体血流和肢体肌肉组织学，并恢复了肌肉功能（力量产生）。与BAG3相比，BAG3在缺血骨骼肌细胞中与小热休克蛋白（HspB8）的结合改善，并且增强了缺血肌肉的自噬通量。
综上所述，我们的数据表明BAG3中的遗传变异在预防缺血性组织坏死中起重要作用。这些结果突出了一条在缺血情况下维持组织存活和肌肉功能的途径。
