Department of Hepatology, Graduate School of Medicine, Osaka City University, Osaka, Japan.
Department of Pediatrics, Hanoi Medical University, Hanoi, Viet Nam.
Redox Biol. 2022 Jun;52:102286. doi: 10.1016/j.redox.2022.102286. Epub 2022 Mar 19.
BACKGROUND & AIMS: Hepatic stellate cells (HSCs) are the primary cell type in liver fibrosis, a significant global health care burden. Cytoglobin (CYGB), a globin family member expressed in HSCs, inhibits HSC activation and reduces collagen production. We studied the antifibrotic properties of globin family members hemoglobin (HB), myoglobin (MB), and neuroglobin (NGB) in comparison with CYGB.
APPROACH & RESULTS: We characterized the biological activities of globins in cultured human HSCs (HHSteCs) and their effects on carbon tetrachloride (CCl)-induced cirrhosis in mice. All globins demonstrated greater antioxidant capacity than glutathione in cell-free systems. Cellular fractionation revealed endocytosis of extracellular MB, NGB, and CYGB, but not HB; endocytosed globins localized to intracellular membranous, cytoplasmic, and cytoskeletal fractions. MB, NGB, and CYGB, but not HB, scavenged reactive oxygen species generated spontaneously or stimulated by HO or transforming growth factor β1 in HHSteCs and reduced collagen 1A1 production via suppressing COL1A1 promoter activity. Disulfide bond-mutant NGB displayed decreased heme and superoxide scavenging activity and reduced collagen inhibitory capacity. RNA sequencing of MB- and NGB-treated HHSteCs revealed downregulation of extracellular matrix-encoding and fibrosis-related genes and HSC deactivation markers. Upregulation of matrix metalloproteinase (MMP)-1 was observed following MB and NGB treatment, and MMP-1 knockdown partially reversed globin-mediated effects on secreted collagen. Importantly, administration of MB, NGB, and CYGB suppressed CCl-induced mouse liver fibrosis.
These findings revealed unexpected roles for MB and NGB in deactivating HSCs and inhibiting liver fibrosis development, suggesting that globin therapy may represent a new strategy for combating fibrotic liver disease.
肝星状细胞（HSCs）是肝纤维化的主要细胞类型，肝纤维化是一种全球范围内严重的医疗保健负担。在 HSCs 中表达的珠蛋白家族成员细胞色素 b2（CYGB）抑制 HSC 激活并减少胶原产生。我们研究了与 CYGB 相比，珠蛋白家族成员血红蛋白（HB）、肌红蛋白（MB）和神经球蛋白（NGB）的抗纤维化特性。
我们在培养的人 HSCs（HHSteCs）中对珠蛋白的生物学活性进行了表征，并在小鼠中研究了它们对四氯化碳（CCl）诱导的肝硬化的影响。所有珠蛋白在无细胞系统中均显示出比谷胱甘肽更强的抗氧化能力。细胞分馏显示细胞外 MB、NGB 和 CYGB 的内吞作用，但 HB 没有；内吞珠蛋白定位于细胞内膜、细胞质和细胞骨架部分。MB、NGB 和 CYGB（但不是 HB）可清除 HO 或转化生长因子 β1 刺激或自发产生的 HHSteCs 中的活性氧，通过抑制 COL1A1 启动子活性减少胶原 1A1 的产生。二硫键突变 NGB 的血红素和超氧化物清除活性降低，胶原抑制能力降低。MB 和 NGB 处理的 HHSteCs 的 RNA 测序显示细胞外基质编码和纤维化相关基因以及 HSC 失活标志物的下调。MB 和 NGB 处理后观察到基质金属蛋白酶（MMP）-1 的上调，并且 MMP-1 的敲低部分逆转了珠蛋白对分泌胶原的影响。重要的是，MB、NGB 和 CYGB 的给药抑制了 CCl 诱导的小鼠肝纤维化。
这些发现揭示了 MB 和 NGB 在失活 HSCs 和抑制肝纤维化发展中的意外作用，表明珠蛋白治疗可能代表了对抗纤维性肝病的新策略。
