Hao Kaili, Nguyen Thanh, Nakada Yuji, Walcott Gregory, Wei Yuhua, Wu Yalin, Garry Daniel J, Yao Peng, Zhang Jianyi
Department of Biomedical Engineering, School of Medicine and School of Engineering, University of Alabama at Birmingham, Birmingham, AL 35294, United States.
Department of Medicine, Division of Cardiovascular Disease, School of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, United States.
Stem Cells. 2025 May 15;43(5). doi: 10.1093/stmcls/sxaf018.
When pigs underwent apical resection (AR) on postnatal day (P) 1 (ARP1) followed by myocardial infarction (MI) on P28, the hearts had little evidence of scarring; meanwhile, hearts underwent MI on P28 without ARP1 showed large infarcts on P56; and the improvement of ARP1 hearts was driven primarily by cardiomyocyte proliferation. AR and MI were performed ~5 mm (AR) and ~20 mm (MI) above the heart apex; thus, we hypothesize that ARP1 preserved the cardiomyocytes cell-cycle throughout the left ventricle, rather than only near the resection site.
Sections of cardiac tissue were collected from the left ventricle of uninjured pigs and from both the border zone (BZ) of AR and uninjured regions (remote zone, [RZ]) in ARP1 hearts. Cardiomyocyte proliferation was evaluated via immunofluorescence analysis of phosphorylated histone 3 [PH3] and symmetric Aurora B (sAuB). Single nucleus RNA sequencing (snRNAseq) data collected from the hearts of fetal pigs, uninjured pigs, and the BZ and RZ of ARP1 pigs was evaluated via our cell-cycle-specific autoencoder to identify proliferating cardiomyocytes.
Cardiomyocyte PH3 and sAuB expression, and percentage of proliferating cardiomyocytes in snRNA data was significantly more common in both BZ and RZ of ARP1 than uninjured hearts but did not differ significantly between the ARP1-BZ and ARP1-RZ at any time point. Heat shock proteins HSPA5 and HSP90B1 were overexpressed at both ARP1-BZ and ARP1-RZ. In AC16 cell, overexpression (and knockdown) of HSPA5-HSP90B1 increased (and decrease) cell-cycle activity.
ARP1 preserved proliferative capacity of cardiomyocytes located throughout the left ventricle.
当仔猪在出生后第1天（P1）接受心尖切除术（AR），随后在P28发生心肌梗死（MI）时，心脏几乎没有瘢痕形成的迹象；与此同时，在P28时未进行P1 AR的心脏在P56时出现大面积梗死；P1 AR心脏的改善主要由心肌细胞增殖驱动。AR和MI分别在心脏心尖上方约5毫米（AR）和约20毫米（MI）处进行；因此，我们假设P1 AR保留了整个左心室心肌细胞的细胞周期，而不仅仅是在切除部位附近。
从未受伤仔猪的左心室以及P1 AR心脏的梗死边缘区（BZ）和未受伤区域（远隔区，[RZ]）收集心脏组织切片。通过对磷酸化组蛋白3 [PH3]和对称极光激酶B（sAuB）进行免疫荧光分析来评估心肌细胞增殖。通过我们的细胞周期特异性自动编码器对从胎猪、未受伤猪以及P1 AR猪的BZ和RZ心脏收集的单核RNA测序（snRNAseq）数据进行评估，以识别增殖的心肌细胞。
在snRNA数据中，心肌细胞PH3和sAuB表达以及增殖心肌细胞的百分比在P1 AR的BZ和RZ中均比未受伤心脏更为常见，但在任何时间点，P1 AR - BZ和P1 AR - RZ之间均无显著差异。热休克蛋白HSPA5和HSP90B1在P1 AR - BZ和P1 AR - RZ中均过表达。在AC16细胞中，HSPA5 - HSP90B1的过表达（和敲低）增加（和降低）了细胞周期活性。
P1 AR保留了整个左心室心肌细胞的增殖能力。
