School of Veterinary and Life Sciences, Murdoch University, Perth, WA, Australia; Curtin Medical School, Curtin Health Innovation Research Institute, Curtin University, Perth, Australia.
Curtin Medical School, Curtin Health Innovation Research Institute, Curtin University, Perth, Australia.
Int J Biochem Cell Biol. 2021 May;134:105933. doi: 10.1016/j.biocel.2021.105933. Epub 2021 Feb 1.
Chronic liver injury is characterised by continuous or repeated epithelial cell loss and inflammation. Hepatic wound healing involves matrix deposition through activated hepatic stellate cells (HSCs) and the expansion of closely associated Ductular Reactions and liver progenitor cells (LPCs), which are thought to give rise to new epithelial cells. In this study, we used the murine thioacetamide (TAA) model to reliably mimic these injury and regeneration dynamics and assess the impact of a recovery phase on subsequent liver injury and fibrosis. Age-matched naïve or 6-week TAA-treated/4-week recovered mice (C57BL/6 J, n = 5-9) were administered TAA for six weeks (C57BL/6 J, n = 5-9). Sera and liver tissues were harvested at key time points to assess liver injury biochemically, by real-time PCR for fibrotic mediators, Sirius Red staining and hydroxyproline assessment for collagen deposition as well as immunofluorescence for inflammatory, HSC and LPC markers. In addition, primary HSCs and the HSC cell line LX-2 were co-cultured with the well-characterised LPC line BMOL and analysed for potential changes in expression of fibrogenic mediators. Our data demonstrate that recovery from a previous TAA insult, with LPCs still present on day 0 of the second treatment, led to a reduced TAA-induced disease progression with less severe fibrosis than in naïve TAA-treated animals. Importantly, primary activated HSCs significantly reduced pro-fibrogenic gene expression when co-cultured with LPCs. Taken together, previous TAA injury established a fibro-protective molecular and cellular microenvironment. Our proof-of principle HSC/LPC co-culture data demonstrate that LPCs communicate with HSCs to regulate fibrogenesis, highlighting a key role for LPCs as regulatory cells during chronic liver disease.
慢性肝损伤的特征是持续或反复的上皮细胞丢失和炎症。肝创伤愈合涉及基质的沉积，这是通过激活的肝星状细胞（HSCs）和紧密相关的胆管反应和肝祖细胞（LPCs）的扩张来实现的，这些细胞被认为产生新的上皮细胞。在这项研究中，我们使用了小鼠硫代乙酰胺（TAA）模型来可靠地模拟这些损伤和再生动力学，并评估恢复阶段对随后的肝损伤和纤维化的影响。将年龄匹配的幼稚或 6 周 TAA 处理/4 周恢复的小鼠（C57BL/6 J，n = 5-9）用 TAA 处理 6 周（C57BL/6 J，n = 5-9）。在关键时间点采集血清和肝脏组织，以通过实时 PCR 评估纤维化介质、天狼星红染色和羟脯氨酸评估胶原沉积以及免疫荧光评估炎症、HSC 和 LPC 标志物来评估肝损伤的生化情况。此外，我们还将原代 HSCs 和 HSC 细胞系 LX-2 与经过充分表征的 LPC 系 BMOL 共培养，并分析潜在的纤维化介质表达变化。我们的数据表明，在第二次治疗的第 0 天仍存在 LPC 的情况下，从先前的 TAA 损伤中恢复过来，导致 TAA 诱导的疾病进展减少，纤维化程度比幼稚的 TAA 处理动物轻。重要的是，当与 LPC 共培养时，原代激活的 HSCs 显著降低了促纤维化基因的表达。总之，先前的 TAA 损伤建立了一个纤维保护的分子和细胞微环境。我们的 HSC/LPC 共培养的原理验证数据表明，LPC 与 HSCs 相互作用来调节纤维化，这突显了 LPC 在慢性肝病中作为调节细胞的关键作用。
