LARP1 acts as a key mediator in preventing angiotensin II-induced cardiac dysfunction and fibrosis

Fig. 1. LARP1 is downregulated in cardiac hypertrophy. A qRT-PCR was used to evaluate the gene expression level of LARP1 in cardiac tissues of patients with myocardial hypertrophy. B Expression of LARP1 protein in cardiac tissues of patients with myocardial hypertrophy was detected by western blot. (n = 10 patients). Data are analyzed using Student’s t-test. **P < 0.01 represents the comparison between the hypertrophy group versus non-hypertrophy group. C qRT-PCR was used to detect LARP1 gene expression levels in the cardiac tissue of mice treated with vehicle or Ang II. D Protein expression level of LARP1 in cardiac tissue of mice treated with vehicle or Ang II was measured by western blot assay. Data are representative of 3 different experiments (10 mice/group) and analyzed using a student t-test. **P < 0.01 represents Ang II group versus Ctrl group. E qRT-PCR detection of mRNA levels of LARP1 in primary cardiomyocytes treated with or without Ang II for different time durations. F Western blot detection of protein levels of LARP1 in primary cardiomyocytes in the indicated groups. G qRT-PCR detection of mRNA levels of LARP1 in cardiac fibroblasts treated with or without Ang II for…

Fig. 2. LARP1 alleviates Ang II-induced cardiomyocyte hypertrophy in vitro. Primary cardiomyocytes were transfected with either an empty vector (nc; negative control) or a LARP1 overexpressing vector (Oe-LARP1) and subsequently treated with or without Ang II for 24 h. A Western blot assay was used to detect protein expression levels of LARP1 in primary cardiomyocytes in the indicated groups. B Immunofluorescence detection assay was used for α-actinin to verify cardiomyocyte hypertrophy under different treatment conditions. Representative images of cardiomyocytes stained with α-actinin are shown in green color, while the nucleus stained with DAPI is shown in blue color. C qRT-PCR and western blot assays were conducted to measure mRNA and protein levels of cardiac remodeling-related biomarkers such as Nppa, Nppb, MyHC, and ANP. Data are analyzed using one-way ANOVA followed by post hoc Tukey’s multiple comparison test. Data are representative of n = 5 different experiments. **P < 0.01 represents versus NC group; ##P < 0.01 represents versus NC + Ang II treated group

Fig. 3. LARP1 regulates cardiac remodelling in vivo. A Schematic diagram of the animal experiment design. Seven-week-old male C57BL/6J mice were randomly divided into four groups: control group (Ctrl), Angiotensin II (Ang II) group, LARP1 group, and Ang II + LARP1 group. The Ang II group received daily subcutaneous administration of Ang II (2 mg/kg/day) after administration of AAV9-NC for four weeks, the LARP1 group received administration of AAV9-LARP1 via tail vein, and the Ang II + LARP1 group received both AAV9-LARP1 and Ang II (2 mg/kg/day). The control group was administered an equal volume of 0.9% NaCl subcutaneously. After four weeks of treatment, LARP1 expression, cardiac function, and histopathological changes in the cardiac tissues of mice were assessed. B qRT-PCR was conducted to measure the gene expression level of LARP1 in different groups of mice. C Detection of ejection fraction in mice with different treatments. D Detection of fractional shortening in the indicated groups of mice. E Detection of gross heart sectional area in different groups of mice. F HE staining, WGA staining, and Picrosirius red staining were performed to measure histopathological changes in the heart…

Fig. 4. ATP2A2 is a downstream target binding to the LARP1 protein. A Volcano plot of the up and down-regulated genes in the GSE227541 dataset. B KEGG enrichment analysis was performed for differentially expressed genes in the GSE227541 dataset. C Venn diagram identifying overlapping genes between LARP1-binding targets predicted in the StarBase database and differentially expressed genes from the GSE227541 dataset. D qRT-PCR was used to detect target gene expression levels in primary cardiomyocytes treated with or without Ang II for 24 h. Data are representative of 3 different experiments and analyzed using Student’s t-test. **P < 0.01 represents versus Ctrl group. E ATP2A2 expression in hypertrophic (HY) and non-hypertrophic (NH) patients in the GSE227541 dataset. F qRT-PCR was performed to assess ATP2A2 mRNA expression levels in the HY and NH human cardiac tissue samples. (n = 10 patients). Data are analyzed using Student’s t-test. **P < 0.01 represents versus non-hypertrophy group. G–I ATP2A2 mRNA and ATP2A2 protein expression in a mouse model injected with Ang II alone or in combination with AAV9-LARP1. qRT-PCR and western blot assays were performed to measure ATP2A2 mRNA and ATP2A2…

Fig. 5. LARP1 alleviates Ang II-induced cardiomyocyte hypertrophy in vitro via ATP2A2. Primary cardiomyocytes were transfected with either an empty vector (nc; negative control) or LARP1 silencing vector (sh-LARP1), or ATPA2A overexpressing vector (Oe-ATPA2A) or together with sh-LARP1 and Oe-ATPA2A vectors and then treated with Ang II for 24 h. A Western blot was used to detect the protein expression level of ATP2A2 and LARP1 in different transfected groups. B Immunofluorescence detection assay was used for α-actinin to verify cardiomyocyte hypertrophy under different treatment conditions. Representative images of cardiomyocytes stained with α-actinin are shown in green color, while the nucleus stained with DAPI is shown in blue color. C, D qRT-PCR and western blot assays were conducted to measure mRNA and protein levels of cardiac remodeling-related biomarkers such as Nppa, Nppb, MyHC, and ANP. Data are analyzed using one-way ANOVA followed by post hoc Tukey’s multiple comparison test. Data are representative of n = 5 different experiments. *P < 0.05, **P < 0.01 represents versus sh-NC group; ###P < 0.001, ####P < 0.0001 represents versus sh-NC and sh-LARP1 groups; &&P < 0.01, &&&&P <…

Fig. 6. LAPR1 ameliorates Ang II-induced cardiac hypertrophy in vivo via ATP2A2. A Schematic diagram of animal experiment design. 7-week-old C57BL/6J male mice (Wild type) and LARP1 gene-deficient mice (LARP1−/−) were randomly divided into four groups (n = 12): Group 1 (WT + vector), Group 2 (LARP1−/− + vector), Group 3 (WT + ATP2A2), and Group 4 (LARP1−/− + ATP2A2). The four groups received a tail vein injection of either an empty vector (AAV9-NC) or AAV9-ATP2A2 for four weeks. Thereafter, mice in the four groups were administered Ang II (2 mg/kg/day) for another four weeks and assessed for cardiac function and histopathology. B Detection of ejection fraction in mice with different treatments. C Detection of fractional shortening in the indicated groups of mice. D Detection of gross heart sectional area in different groups of mice. E HE staining, WGA staining, Masson staining, and Picrosirius red staining were performed to measure histopathological changes in the heart tissues of mice with different treatments. F–I qRT-PCR and western blot assays were performed to measure mRNA and protein levels of hypertrophy markers (MyHC, ANP) and fibrosis markers (Col-I, TGF-β) in the indicated…