[Investigation on the signaling pathways in the mechanism of hyperoxia-induced acute lung injury based on transcriptomics sequencing].

OBJECTIVE: To observe and verify the changes of transcriptome in hyperoxia-induced acute lung injury (HALI), and to further clarify the changes of pathways in HALI. METHODS: Twelve healthy male C57BL/6J mice were randomly divided into normoxia group and HALI group according to the random number table, with 6 mice in each group. The mice in the normoxia group were fed normally in the room, and the mice in the HALI group was exposed to 95% oxygen to reproduce the HALI animal model. After 72 hours of hyperoxia exposure, the lung tissues were taken for transcriptome sequencing, and then Kyoto Encyclopedia of Genes and Genomes database (KEGG) pathway enrichment analysis was performed. The pathological changes of lung tissue were observed under light microscope after hematoxylin-eosin (HE) staining. Real-time fluorescence quantitative reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting were used to verify the key molecules in the signal pathways closely related to HALI identified by transcriptomics analysis. RESULTS: Transcriptomic analysis showed that hyperoxia induced 537 differentially expressed genes in lung tissue of mice as compared with the normoxia group including 239 up-regulated genes and 298 down-regulated genes. Further KEGG pathway enrichment analysis identified 20 most significantly enriched pathway entries, and the top three pathways were ferroptosis signaling pathway, p53 signaling pathway and glutathione (GSH) metabolism signaling pathway. The related genes in the ferroptosis signaling pathway included the up-regulated gene heme oxygenase-1 (HO-1) and the down-regulated gene solute carrier family 7 member 11 (SLC7A11). The related genes in the p53 signaling pathway included the up-regulated gene tumor suppressor gene p53 and the down-regulated gene murine double minute 2 (MDM2). The related gene in the GSH metabolic signaling pathway was up-regulated gene glutaredoxin 1 (Grx1). The light microscope showed that the pulmonary alveolar structure of the normoxia group was normal. In the HALI group, the pulmonary alveolar septum widened and thickened, and the alveolar cavity shrank or disappeared. RT-RCR and Western blotting confirmed that compared with the normoxia group, the mRNA and protein expressions of HO-1 and p53 in lung tissue of the HALI group were significantly increased [HO-1 mRNA (2-ΔΔCt): 2.16±0.17 vs. 1.00±0.00, HO-1 protein (HO-1/ß-actin): 1.05±0.01 vs. 0.79±0.01, p53 mRNA (2-ΔΔCt): 2.52±0.13 vs. 1.00±0.00, p53 protein (p53/ß-actin): 1.12±0.02 vs. 0.58±0.03, all P < 0.05], and the mRNA and protein expressions of Grx1, MDM2, SLC7A11 were significantly decreased [Grx1 mRNA (2-ΔΔCt): 0.53±0.05 vs. 1.00±0.00, Grx1 protein (Grx1/ß-actin): 0.54±0.03 vs. 0.93±0.01, MDM2 mRNA (2-ΔΔCt): 0.48±0.03 vs. 1.00±0.00, MDM2 protein (MDM2/ß-actin): 0.57±0.02 vs. 1.05±0.01, SLC7A11 mRNA (2-ΔΔCt): 0.50±0.06 vs. 1.00±0.00, SLC7A11 protein (SLC7A11/ß-actin): 0.72±0.03 vs. 0.98±0.01, all P < 0.05]. CONCLUSIONS: HALI is closely related to ferroptosis, p53 and GSH metabolism signaling pathways. Targeting the key targets in ferroptosis, p53 and GSH metabolism signaling pathways may be an important strategy for the prevention and treatment of HALI.

Annexin-A1 short peptide alleviates septic myocardial injury by upregulating SIRT3 and inhibiting myocardial cell apoptosis.

Septic myocardial injury is a common complication of severe sepsis, which occurs in about 50% of cases. Patients with this disease may experience varying degrees of myocardial damage. Annexin-A1 short peptide (ANXA1sp), with a molecular structure of Ac-Gln-Ala-Tyr, has been reported to exert an organ protective effect in the perioperative period by modulating sirtuin-3 (SIRT3). Whether it possesses protective activity against sepsis-induced cardiomyopathy is worthy of study. This study aimed to investigate whether ANXA1sp exerts its anti-apoptotic effect in septic myocardial injury in vitro and in vivo via regulating SIRT3. In this study, we established in vivo and in vivo models of septic myocardial injury based on C57BL/6 mice and primary cardiomyocytes by lipopolysaccharide (LPS) induction. Results showed that ANXA1sp pretreatment enhanced the seven-day survival rate, improved left ventricular ejection fraction (EF), left ventricular fractional shortening (FS), and cardiac output (CO), and reduced the levels of creatine kinase-MB (CK-MB), cardiac troponin I (cTnI), and lactate dehydrogenase (LDH). Western blotting results revealed that ANXA1sp significantly increased the expression of SIRT3, Bcl-2, and downregulated Bax expression. TUNEL staining and flow cytometry results showed that ANXA1sp could attenuate the apoptosis rate of cardiomyocytes, whereas this anti-apoptotic effect was significantly attenuated after SIRT3 knockout. To sum up, ANXA1sp can alleviate LPS-induced myocardial injury by reducing myocardial apoptosis via SIRT3 upregulation.

Gpnmb silencing protects against hyperoxia-induced acute lung injury by inhibition of mitochondrial-mediated apoptosis.

Background: Hyperoxia-induced acute lung injury (HALI) is a complication to ventilation in patients with respiratory failure, which can lead to acute inflammatory lung injury and chronic lung disease. The aim of this study was to integrate bioinformatics analysis to identify key genes associated with HALI and validate their role in H2O2-induced cell injury model.Methods: Integrated bioinformatics analysis was performed to screen vital genes involved in hyperoxia-induced lung injury (HLI). CCK-8 and flow cytometry assays were performed to assess cell viability and apoptosis. Western blotting was performed to assess protein expression.Results: In this study, glycoprotein non-metastatic melanoma protein B (Gpnmb) was identified as a key gene in HLI by integrated bioinformatics analysis of 4 Gene Expression Omnibus (GEO) datasets (GSE97804, GSE51039, GSE76301 and GSE87350). Knockdown of Gpnmb increased cell viability and decreased apoptosis in H2O2-treated MLE-12 cells, suggesting that Gpnmb was a proapoptotic gene during HALI. Western blotting results showed that knockdown of Gpnmb reduced the expression of Bcl-2 associated X (BAX) and cleaved-caspase 3, and increased the expression of Bcl-2 in H2O2 treated MLE-12 cells. Furthermore, Gpnmb knockdown could significantly reduce reactive oxygen species (ROS) generation and improve the mitochondrial membrane potential.Conclusion: The present study showed that knockdown of Gpnmb may protect against HLI by repressing mitochondrial-mediated apoptosis.

Hyperoxia can Induce Lung Injury by Upregulating AECII Autophagy and Apoptosis Via the mTOR Pathway.

Oxygen therapy is a crucial medical intervention, but it is undeniable that it can lead to lung damage. The mTOR pathway plays a pivotal role in governing cell survival, including autophagy and apoptosis, two phenomena deeply entwined with the evolution of diseases. However, it is unclarified whether the mTOR pathway is involved in hyperoxic acute lung injury (HALI). The current study aims to clarify the molecular mechanism underlying the pathogenesis of HALI by constructing in vitro and in vivo models using H2O2 and hyperoxia exposure, respectively. To investigate the role of mTOR, the experiment was divided into five groups, including normal group, injury group, mTOR inhibitor group, mTOR activator group, and DMSO control group. Western blotting, Autophagy double labeling, TUNEL staining, and HE staining were applied to evaluate protein expression, autophagy activity, cell apoptosis, and pathological changes in lung tissues. Our data revealed that hyperoxia can induce autophagy and apoptosis in Type II alveolar epithelial cell (AECII) isolated from the treated rats, as well as injuries in the rat lung tissues; also, H2O2 stimulation increased autophagy and apoptosis in MLE-12 cells. Noticeably, the experiments performed in both in vitro and in vivo models proved that the mTOR inhibitor Rapamycin (Rapa) functioned synergistically with hyperoxia or H2O2 to promote AECII autophagy, which led to increased apoptosis and exacerbated lung injury. On the contrary, activation of mTOR with MHY1485 suppressed autophagy activity, consequently resulting in reduced apoptosis and lung injury in H2O2-challenged MLE-12 cells and hyperoxia-exposed rats. In conclusion, hyperoxia caused lung injury via mTOR-mediated AECII autophagy.

[Wedelolactone alleviates hyperoxia-induced acute lung injury by regulating ferroptosis].

OBJECTIVE: To study whether wedelolactone can reduce hyperoxia-induced acute lung injury (HALI) by regulating ferroptosis, and provide a basic theoretical basis for the drug treatment of HALI. METHODS: A total of 24 C57BL/6J mice were randomly divided into normal oxygen control group, HALI model group and wedelolactone pretreatment group, with 8 mice in each group. Mice in wedelolactone pretreatment group were treated with wedelolactone 50 mg/kg intraperitoneally for 6 hours, while the other two groups were not given with wedelolactone. After that, the HALI model was established by maintaining the content of carbon dioxide < 0.5% and oxygen > 90% in the molding chamber for 48 hours, and the normal oxygen control group was placed in indoor air. After modeling, the mice were sacrificed and lung tissues were collected. The lung histopathological changes were observed under light microscope and pathological scores were performed to calculate the ratio of lung wet/dry mass (W/D). The levels of tumor necrosis factor-α (TNF-α), interleukins (IL-6, IL-1ß), superoxide dismutase (SOD), malondialdehyde (MDA) and glutathione (GSH) in lung tissues of mice in each group were determined. The protein expression of glutathione peroxidase 4 (GPX4) in lung tissue was detected by Western blotting. RESULTS: Under light microscope, the alveolar structure of HALI model group was destroyed, and a large number of neutrophils infiltrated the alveolar and interstitial lung, and the interstitial lung was thickened. The pathological score of lung injury (score: 0.75±0.02 vs. 0.11±0.01) and the ratio of lung W/D (6.23±0.34 vs. 3.68±0.23) were significantly higher than those in the normal oxygen control group (both P < 0.05). Wedelolactone pretreated mice had clear alveolar cavity and lower neutrophil infiltration and interstitial thickness than HALI group. Pathological scores (score: 0.43±0.02 vs. 0.75±0.02) and W/D ratio (4.56±0.12 vs. 6.23±0.34) were significantly lower than HALI group (both P < 0.05). Compared with the normal oxygen control group, the levels of SOD (kU/g: 26.41±4.25 vs. 78.64±3.95) and GSH (mol/g: 4.51±0.33 vs. 12.53±1.25) in HALI group were significantly decreased, while the levels of MDA (mmol/g: 54.23±4.58 vs. 9.65±1.96), TNF-α (µg/L: 96.32±3.67 vs. 11.65±2.03), IL-6 (ng/L: 163.35±5.89 vs. 20.56±3.63) and IL-1ß (µg/L: 72.34±4.64 vs. 15.64±2.47) were significantly increased, and the protein expression of GPX4 (GPX4/ß-actin: 0.44±0.02 vs. 1.00±0.09) was significantly decreased (all P < 0.05). Compared with the HALI group, the levels of SOD (kU/g: 53.28±3.69 vs. 26.41±4.25) and GSH (mol/g: 6.73±0.97 vs. 12.53±1.25) were significantly higher in the wedelolactone pretreatment group, and the levels of MDA (mmol/g: 25.36±1.98 vs. 54.23±4.58), TNF-α (µg/L: 40.25±4.13 vs. 96.32±3.67), IL-6 (ng/L: 78.32±4.65 vs. 163.35±5.89), and IL-1ß (µg/L: 30.65±3.65 vs. 72.34±4.64) were significantly lower (all P < 0.05), and protein expression of GPX4 was significantly higher (GPX4/ß-actin: 0.68±0.04 vs. 0.44±0.02, P < 0.05). CONCLUSIONS: Wedelolactone attenuates HALI injury by regulating ferroptosis.

ROS-mediated MAPK activation aggravates hyperoxia-induced acute lung injury by promoting apoptosis of type II alveolar epithelial cells via the STAT3/miR-21-5p axis.

Inhibition of type II alveolar epithelial (AE-II) cell apoptosis is a critical way to cure hyperoxia-induced acute lung injury (HALI). It has been reported that miR-21-5p could reduce H2O2-induced apoptosis in AE-II cells. However, the upstream molecular mechanism remains unclear. Herein, we established a cellular model of HALI by exposing AE-II cells to H2O2 treatment. It was shown that miR-21-5p alleviated H2O2-induced apoptosis in AE-II cells. ROS inhibition decreased apoptosis of H2O2-evoked AE-II cells via increasing miR-21-5p expression. In addition, ROS induced MAPK and STAT3 phosphorylation in H2O2-treated AE-II cells. MAPK inactivation reduces H2O2-triggered AE-II cell apoptosis. MAPK activation inhibits miR-21-5p expression by promoting STAT3 phosphorylation in H2O2-challenged AE-II cells. Furthermore, STAT3 activation eliminated MAPK deactivation-mediated inhibition on the apoptosis of AE-II cells under H2O2 condition. In conclusion, ROS-mediated MAPK activation promoted H2O2-triggered AE-II cell apoptosis by inhibiting miR-21-5p expression via STAT3 phosphorylation, providing novel targets for HALI treatment.

ANXA1sp Protects against Sepsis-Induced Myocardial Injury by Inhibiting Ferroptosis-Induced Cardiomyocyte Death via SIRT3-Mediated p53 Deacetylation.

Sepsis-induced myocardial injury (SIMI), a common complication of sepsis, may cause significant mortality. Ferroptosis, a cell death associated with oxidative stress and inflammation, has been identified to be involved in SIMI. This study sought to investigate the role of ANXA1 small peptide (ANXA1sp) in SIMI pathogenesis. In this study, the mouse cardiomyocytes (H9C2 cells) were stimulated with lipopolysaccharide (LPS) to imitate SIMI in vitro. It was shown that ANXA1sp treatment substantially abated LPS-triggered H9C2 cell death and excessive secretion of proinflammatory cytokines (TNF-α, IL-1ß, and IL-6). ANXA1sp pretreatment also reversed the increase of ROS and MDA generation as well as the decrease of SOD and GSH activity in H9C2 cells caused by LPS treatment. In addition, ANXA1sp considerably eliminated LPS-caused H9C2 cell ferroptosis, as revealed by the suppression of iron accumulation and the increase in GPX4 and FTH1 expression. Furthermore, the ameliorative effects of ANXA1sp on LPS-induced H9C2 cell damage could be partially abolished by erastin, a ferroptosis agonist. ANXA1sp enhanced SIRT3 expression in LPS-challenged H9C2 cells, thereby promoting p53 deacetylation. SIRT3 knockdown diminished ANXA1sp-mediated alleviation of cell death, inflammation, oxidative stress, and ferroptosis of LPS-treated H9C2 cells. Our study demonstrated that ANXA1sp is protected against LPS-induced cardiomyocyte damage by inhibiting ferroptosis-induced cell death via SIRT3-dependent p53 deacetylation, suggesting that ANXA1sp may be a potent therapeutic agent for SIMI.

[MicroRNA21-5p alleviates hyperoxia-induced acute lung injury in rats through activating phosphatidylinositol 3 kinase/serine-threonine protein kinase signaling pathway by regulating type II alveolar epithelial cell apoptosis].

OBJECTIVE: To investigate whether microRNA-21-5p (miR-21-5p) alleviates hyperoxia-induced acute lung injury (HALI) through activating the phosphatidylinositol 3 kinase/serine-threonine protein kinase (PI3K/Akt) signaling pathway by regulating apoptosis of type II alveolar epithelial cell (AEC II). METHODS: Seventy-two male Sprague-Dawley (SD) rats were divided into normozone-controlled group, HALI group, PI3K/Akt signaling pathway inhibitor LY294002+HALI group (LY+HALI group), miR-21-5p overexpression+LY294002+HALI group (miR-21-5p+LY+HALI group), miR-21-5p overexpression+HALI group (miR-21-5p+HALI group), and dimethyl sulfoxide (DMSO)+HALI group by random number table method with 12 rats in each group. Animal models of HALI were prepared using 95% concentrations of oxygen. The animals in the normozone-controlled group were fed normally under normoxia. Transfection of lung tissue by miR-21-5p adeno-associated viral vector AAV6-miR-21-5p was performed by instillation of 200 µL titer (1×1012 TU/mL) through a tracheal catheter 3 weeks prior to modeling. DMSO and LY294002 were administered via the tail vein at 0.3 mg/kg 1 hour before modeling. After 48 hours of modeling, carotid artery blood was collected to detect oxygenation index (OI) and respiratory index (RI), and real-time fluorescence quantitative reverse transcription-polymerase chain reaction (RT-PCR) was used to detect miR-21-5p expression. Lung tissue was collected, and the levels of inflammatory factors including tumor necrosis factor-α (TNF-α) and interleukins (IL-6, IL-1ß) were measured by enzyme-linked immunosorbent assay (ELISA), and the ratio of pulmonary wet/dry weight (W/D) was determined, and the pathological changes of lung histopathology were observed under the light microscopy after hematoxylin-eosin (HE) staining. Each group was purified AEC II cells from 6 rats, the apoptosis rate was detected by flow cytometry, and the expression levels of phosphatase and tensin homologous gene (PTEN), and proteins from the PI3K/Akt signaling pathway were detected by Western blotting. RESULTS: Compared with the normozone-controlled group, alveolar septal thickening and massive inflammatory cell infiltration were found after hyperoxia exposure, RI, inflammatory factors, lung W/D ratio, pathological score, AEC II cells early apoptosis rate, PTEN protein expression and phosphorylation level of Akt were increased, while OI and miR-21-5p expression were decreased, indicating the successful preparation of the model. After pretreatment, LY294002 could aggravate the pathological injury of lung tissue in HALI rats, RI, inflammatory factors and lung W/D ratio were further increased, and OI was further reduced compared with HALI group. At the same time, it could promote the AEC II cell apoptosis, further up-regulate the expression of PTEN, and reduce the phosphorylation of Akt. However, miR-21-5p pretreatment could negatively regulate PTEN, activate PI3K/Akt signal pathway, inhibit AEC II cell apoptosis, and reduce HALI, which was shown by the decreased level of inflammatory factors in miR-21-5p+LY+HALI group compared with LY+HALI group [TNF-α (µg/L): 100.33±3.48 vs. 116.55±2.53, IL-6 (ng/L): 141.06±3.70 vs. 161.31±3.59, IL-1ß (µg/L): 90.82±3.69 vs. 112.23±2.87, all P < 0.05], RI, lung injury pathology score, lung W/D ratio, and AEC II cell early apoptosis rate were significantly decreased [RI: 0.81±0.02 vs. 1.05±0.07, pathology score: 0.304±0.008 vs. 0.359±0.007, lung W/D ratio: 5.29±0.03 vs. 5.52±0.08, apoptosis rate: (27.20±2.34)% vs. (34.17±1.49)%, all P < 0.05], OI and expressions of miR-21-5p were significantly increased [OI (mmHg, 1 mmHg ≈ 0.133 kPa): 266.71±2.75 vs. 230.12±4.04, miR-21-5p (2-ΔΔCt): 2.21±0.13 vs. 0.33±0.03, both P < 0.05], and PTEN protein expression in AEC II cell was significantly reduced (PTEN/GAPDH: 0.50±0.06 vs. 0.93±0.06, P < 0.05), and phosphorylation level of Akt was significantly increased [phosphorylated Akt (p-Akt) protein (p-Akt/GAPDH): 0.86±0.05 vs. 0.56±0.06, P < 0.05]. CONCLUSIONS: miR-21-5p attenuates HALI by inhibiting AEC II cell apoptosis, possibly through negative regulation of PTEN to activate PI3K/Akt signaling pathway.

[Role and mechanism of signal transducer and activator of transcription protein STAT1/3/5 in hyperoxia-induced acute lung injury].

OBJECTIVE: To investigate whether signal transducer and activator of transcription (STAT1/3/5) have a protective effect on hyperoxia-induced acute lung injury (HALI) and its mechanism. METHODS: Seventy C57BL/6J mice were randomly divided into five groups: normoxia control group, HALI group, and STAT1/3/5 inhibitor groups, with 14 mice in each group. The HALI model was established by exposure to more than 90% hyperoxia for 48 hours; three STAT inhibitor groups were pretreated by intraperitoneal injection of STAT1 inhibitor 40 mg/kg and STAT3 inhibitor 5 mg/kg, and STAT5 inhibitor 10 mg/kg for 1 week. Six blood samples were randomly collected from each group, and microRNA-21 (miR-21) expression was measured by quantitative real-time reverse transcription-polymerase chain reaction (RT-PCR). Lung tissue of the sacrificed mice was obtained, and enzyme linked immunosorbent assay (ELISA) was used to detect the contents of tumor necrosis factor-α (TNF-α), interleukins (IL-6, IL-1ß), superoxide dismutase (SOD), malonic dialdehyde (MDA), and matrix metalloproteinase 9 (MMP9). The water content of lung tissue was calculated. The pathological changes in lung tissue were observed under the light microscope, and the pathological score of lung injury was performed. Western blotting was used to detect the expression of phosphorylated STAT (p-STAT1, p-STAT3, p-STAT5) in lung tissue. The 7-day cumulative survival rates of the remaining 8 mice in each group were analyzed using Kaplan-Meier survival curves. RESULTS: Under the light microscope, the alveolar structures in the HALI group and the STAT1 inhibitor group were destroyed, a large number of neutrophils (NEU) infiltrated in the alveoli and lung interstitium, which were thickened. The pathological score of lung injury and the water content of the lung tissue was significantly increased. In STAT3 inhibitor and STAT5 inhibitor groups, the alveolar cavity was clear, the degree of NEU infiltration and the thickness of lung interstitium were lower than those in HALI group, the pathological score of lung injury and the water content of lung tissue were significantly decreased, especially in STAT3 inhibitor group. Compared with the normoxia control group, the contents of TNF-α, IL-6, IL-1ß, MDA, and MMP9, and the expression levels of p-STAT3 and p-STAT5 in the HALI group were significantly increased. In contrast, the content of SOD and the expression of miR-21 were significantly decreased. Compared with the HALI group, the contents of TNF-α, IL-6, IL-1ß, MDA, and MMP9 in the STAT3 inhibitor group and STAT5 inhibitor group were significantly decreased. At the same time, the content of SOD and the expression of miR-21 were significantly increased, especially in STAT3 inhibitor group [TNF-α (µg/L): 42.53±3.25 vs. 86.36±5.48, IL-6 (ng/L): 68.46±4.28 vs. 145.00±6.89, IL-1ß (µg/L): 28.74±3.53 vs. 68.00±5.64, MDA (µmol/g): 20.33±2.74 vs. 42.58±3.45, and MMP9 (ng/L): 128.55±6.35 vs. 325.13±6.65, SOD (kU/g): 50.53±4.19 vs. 22.53±3.27, miR-21 (2-ΔΔCt): 0.550±0.018 vs. 0.316±0.037, all P < 0.05]. Kaplan-Meier survival curve analysis showed that the 7-day cumulative survival rates of the STAT3 inhibitor group and STAT5 inhibitor group were significantly higher than those of the HALI group [62.5% (5/8), 37.5% (3/8) vs. 12.5% (1/8), both P < 0.05]. CONCLUSIONS: Inhibition of STAT3 hyperactivation may suppress the inflammatory response, regulate oxidative stress, improve lung permeability through regulating the expression of miR-21, which exert lung protection in HALI.

[Research progress of extracellular vesicle microRNA in acute lung injury].

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are characterized by the destruction of the barrier function of alveolar epithelial cells and capillary endothelial cells and the recruitment of inflammatory cells, which leads to alveolar and interstitial edema, hyaline membrane formation and inflammatory infiltration of the lungs, etc. The mechanism is not completely defined. The current treatment plan focuses on comprehensive treatments such as ventilator support treatment, fluid management, and nutritional support, but the prognosis is still poor. Studies have shown that extracellular vesicle microRNA (miRNA) from different sources participate in regulating the function of epithelial cells, endothelial cells and phagocytes in different ways, thus aggravating or improving ALI, and have diagnostic, differential diagnosis and the therapeutic value. In this article, the mechanism, diagnostic and differerntial value of extracellular vesicle miRNA from different sources in ALI and the therapy of extracellular vesicle miRNA from stem cell in ALI are reviewed.

[Advance in research of microRNA-21-5p regulate autophagy by targeting gene].

OBJECTIVE: Autophagy is a dynamic process that degrades intracellular proteins and damaged organelles, and maintains environmental stability within the cell and provides good conditions for cell survival. Hyperoxic acute lung injury (HALI) is one of the serious complications of clinical oxygen therapy. The pathogenesis of HALI is still unclear. There are studies having shown that autophagy is involved in the pathogenesis of HALI. There are many pathway mechanisms that regulate autophagy, including phosphatidylinositol-3-kinase/Akt/mammalian target of rapamycin (PI3K/Akt/mTOR) signaling pathway, mitogen-activated protein kinase/extracellular signaling-regulated protein kinase (MAPK/ERK) signaling pathway, adenosine 5'-monophosphate-activated protein kinase/unc-51 like autophagy activating kinase 1 (AMPK/ULK1) signaling pathway, transforming growth factor ß (TGF-ß) and forkhead box O1 (FoxO1) and Ras guanosine triphosphatease superfamily member Rab11a, each of which is referred to as microRNA-21-5p (miR-21-5p) target gene having a role in regulating autophagy activity in many diseases. In this paper, the above-mentioned signaling pathways of miRNA-21-5p target genes regulating autophagy were reviewed in order to find clues about the mechanism of miRNA-21-5p regulating autophagy in HALI and provide a theoretical basis for subsequent basic research.