MiR-539-5p inhibits the inflammatory injury in septic H9c2 cells by regulating IRAK3

Inflammation Response ◽

Over Expression ◽

Qrt Pcr ◽

Gene Assay ◽

Proliferation And Apoptosis

Abstract Background MicroRNAs (miRNAs) have been confirmed to play a potential role in sepsis, but little is known about their role in sepsis-induced cardiomyopathy (SIC). Methods The model of septic cardiomyopathy was constructed with H9c2 cells induced by lipopolysaccharide (LPS), and the expression of miR-539-5p was detected by qRT-PCR assay. ELISA, CCK-8, EdU TUNEL analysis were performed to evaluate the role of miR-539-5p in inflammation response, viability, proliferation and apoptosis of LPS-treated H9c2 cells. Moreover, miRWalk and TargetScan prediction, and dual-luciferase reporter gene assays were carried out to predict and confirm the target of miR-539-5p. Furthermore, the effects of target on inflammation response, proliferation and apoptosis of LPS-induced H9c2 cells mediated by miR-539-5p was further explored. Results The expression of miR-539-5p was obviously down-regulated in LPS-induced H9c2 cells. In addition, over-expression of miR-539-5p significantly inhibited the inflammation response, promoted viability and proliferation, and suppressed apoptosis of LPS-treated H9c2 cells. Moreover, interleukin-1 receptor-associated kinase 3 (IRAK3) was verified as a target of miR-539-5p by dual-luciferase reporter gene assay. Besides, IRAK3 was highly expressed in H9c2 cells transfected with miR-539-5p inhibitor detected with qRT-PCR and western blot assays. Furthermore, over-expression of IRAK3 partially weakened the effects of miR-539-5p mimic on the inflammation response, proliferation and apoptosis of LPS-induced H9c2 cells. Conclusions MiR-539-5p potentially plays an important role in the pathogenesis of LPS-induced sepsis by targeting IRAK3, suggesting that miR-539-5p may be a potential new target for the treatment of LPS-induced sepsis.

Circ_0000005 Facilitates Proliferation, Apoptosis, Migration and Invasion of Acute Myeloid Leukemia Cells via Modulating miR-139-5p/Tspan3 Axis

10.21203/rs.3.rs-57994/v1 ◽

2020 ◽

Author(s):

Juan Tong ◽

Huilan Liu ◽

Changcheng Zheng ◽

Xiaoyu Zhu ◽

Xiang Wan ◽

...

Keyword(s):

Western Blot ◽

Cell Lines ◽

Reporter Gene ◽

Reporter Gene Assay ◽

Luciferase Reporter ◽

Regulatory Function ◽

Qrt Pcr ◽

Abstract Background: Accumulating circular RNAs (circRNAs) are reported to be abnormally expressed in diverse cancers, hematologic malignancies included. This study aimed to investigate the biological function and underlying mechanisms of circ_0000005 in acute myeloid leukemia (AML).Materials and methods: Bone marrow samples were enrolled from AML patients with normal samples as controls. Circ_0000005, miR-139-5p and tetraspanin 3 (Tspan3) were detected by qRT-PCR and Western blot, respectively. AML cell lines (KG1 and HL60) were used as cell models. CCK-8, Transwell and flow cytometry assays were adopted to study the biological functions of circ_0000005 on AML cells in vitro. The interrelation between circ_0000005 and miR-139-5p was detected by bioinformatics, qRT-PCR, luciferase reporter gene assay, RNA pull-down assay, and RNA-binding protein immunoprecipitation (RIP) assays. Ultimately, Western blot, qRT-PCR, luciferase reporter gene assay were adopted to corroborate the interrelation between miR-139-5p and its target Tspan3. Results: Circ_0000005 was demonstrably elevated in both AML clinical samples and cell lines. Circ_0000005 overexpression promoted the viability, migration and invasion of AML cells, and repressed the apoptosis of AML cells, while silencing circ_0000005 showed opposite biological effects. Circ_0000005 interacted with miR-139-5p and repressed its expression, and Tspan3 was proved to be negatively regulated by miR-139-5p. Circ_0000005 could promote the expression of Tspan3 via repressing miR-139-5p, and the oncogenic functions of circ_0000005 were dependent on its regulatory function on miR-139-5p/Tspan3 axis.Conclusion: Circ_0000005 facilitates the malignant phenotypes of AML cells via miR-139-5p/Tspan3 axis. Circ_0000005 may serve as a potential therapeutic target in AML.

Knockdown of lncRNA HOTTIP Inhibits Retinoblastoma Progression by Modulating the miR-101-3p/STC1 Axis

Technology in Cancer Research & Treatment ◽

10.1177/1533033821997831 ◽

2021 ◽

Vol 20 ◽

pp. 153303382199783

Author(s):

XiangWen Yuan ◽

Zhaoyan Sun ◽

Congxian Cui

Keyword(s):

Cell Proliferation ◽

Western Blotting ◽

Underlying Mechanism ◽

Luciferase Reporter ◽

Qrt Pcr ◽

Gene Assay ◽

Proliferation And Apoptosis ◽

Y79 Cells

Objective: Retinoblastoma (RB) is a frequent eye cancer in children. Long non-coding RNA (LncRNA) HOXA transcript at the distal tip (HOTTIP) is aberrantly expressed in cancer tissues. This study explores the underlying mechanism of lncRNA HOTTIP in RB. Methods: HOTTIP expression in normal retinal cells and RB cell lines was detected using qRT-PCR. The proliferation of RB cells was measured using CCK-8 and EdU assays, and apoptosis was detected using flow cytometry and Western blotting after the transfection of si-HOTTIP into Y79 cells and pc-HOTTIP into HXO-RB-44 cells. The target relationships between HOTTIP and miR-101-3p, and miR-101-3p and STC1 were predicted by bioinformatics website and verified using dual-luciferase reporter gene assay. The binding of HOTTIP and miR-101-3p was verified using RNA pull-down assay. STC1 mRNA and protein in RB cells were measured using qRT-PCR and Western blotting. Moreover, si-HOTTIP and in-miR-101-3p/in-NC, and si-HOTTIP and pc-STC1/pcDNA were co-transfected into Y79 cells respectively to evaluate cell proliferation and apoptosis. Xenograft study was conducted, and Ki67-positive expression was detected using immunohistochemical staining. Results: HOTTIP expression was promoted in RB tissues and cells. Downregulation of HOTTIP inhibited proliferation and promoted apoptosis of Y79 cells, while upregulation of HOTTIP promoted proliferation and inhibited apoptosis of HXO-RB-44 cells. There were target relationships between HOTTIP and miR-101-3p, and miR-101-3p and STC1. Inhibition of miR-101-3p or overexpression of STC1 reversed the effect of si-HOTTIP on the proliferation and apoptosis of RB cells. Xenograft study showed that knockdown of HOTTIP suppressed the growth of RB in vitro. Conclusion: It could be concluded that HOTTIP sponged miR-101-3p to upregulate STC1 expression, thereby promoting RB cell proliferation and inhibiting apoptosis.

Hsa_circ_0060927 Is a Novel Tumor Biomarker by Sponging miR-195-5p in the Malignant Transformation of OLK to OSCC

Frontiers in Oncology ◽

10.3389/fonc.2021.747086 ◽

2022 ◽

Vol 11 ◽

Author(s):

Siming Xu ◽

Yuhan Song ◽

Yanxiong Shao ◽

Haiwen Zhou

Keyword(s):

Cell Proliferation ◽

Reporter Gene ◽

Reporter Gene Assay ◽

Luciferase Reporter ◽

Qrt Pcr ◽

Cerna Network ◽

Gene Assay ◽

And Migration

ObjectiveTo investigate the clinical significance of differentially expressed circRNAs and candidate circRNAs in the transformation of oral leukoplakia (OLK) to oral squamous cell carcinoma (OSCC).MethodsWe performed high-throughput circRNA sequencing in six cases of normal oral mucosal (NOM) tissues, six cases of OLK tissues, and six cases of OSCC tissues. Ten circRNAs with significant differential expression were verified by qRT-PCR. Enzyme tolerance assay and Sanger sequencing were performed on the screened target circRNA hsa_circ_0060927, and a qRT-PCR assay of hsa_circ_0060927 was performed in three tissues (24 cases in each group); this was followed by an ROC analysis. The ceRNA network was predicted using TargetScan and miRanda. MiR-195-5p and TRIM14 were selected as the downstream research objects of hsa_circ_0060927. The sponge mechanism of hsa_circ_0060927 was detected by AGO2 RIP. The interaction between hsa_circ_0060927 and miR-195-5p was verified by RNA pull-down assay and dual luciferase reporter gene assay. The expressions of hsa_circ_0060927, miR-195-5p, and TRIM14 were verified by normal oral epithelial primary cells and cell lines of LEUK1, SCC9, and SCC25. The hsa_circ_0060927 overexpressed plasmid and miR-195-5p mimics were constructed to transfection LEUK1 to detect the changes in cell proliferation, apoptosis, and migration.ResultsThe results of qRT-PCR validation were consistent with the sequencing results. Hsa_circ_0060927 is a true circRNA with trans-splicing sites. The expression of hsa_circ_0060927 increased in NOM, OLK, and OSCC. Overexpression of hsa_circ_0060927 enhanced the ability of cell proliferation and migration, and decreased cell apoptosis capacity. The prediction of ceRNA network suggested that hsa_circ_0060927 could regulate the target gene TRIM14 through sponging miR-195-5p. AGO2 RIP indicated that hsa_circ_0060927 had a sponge mechanism. RNA pull-down and dual luciferase reporter gene assay suggested that hsa_circ_0060927 interacted with miR-195-5p. Hsa_circ_0060927 was positively correlated with the expression of TRIM14, and could relieve the inhibition of miR-195-5p on TRIM14 to regulate cell proliferation, apoptosis, and migration of LEUK1 cells.ConclusionHsa_circ_0060927 acted as a potential key ceRNA to sponge downstream miR-195-5p and promote OLK carcinogenesis by upregulating TRIM14. Hsa_circ_0060927 was expected to be a molecular marker for the prevention and treatment of OLK carcinogenesis through the hsa_circ_0060927/miR-195-5p/TRIM14 axis.

miR-138-5p inhibits the metastasis of prostate cancer by targeting FOXC1

10.21203/rs.3.rs-16546/v1 ◽

2020 ◽

Author(s):

Dapeng Zhang ◽

Xiaodong Liu ◽

Qingwei Zhang ◽

Xin Chen

Keyword(s):

Cell Lines ◽

Poor Prognosis ◽

Bioinformatics Analysis ◽

Reporter Gene Assay ◽

Luciferase Reporter ◽

Over Expression ◽

Qrt Pcr ◽

Abstract Background: This study aimed to uncover the regulatory effect of miR-138-5p on the metastasis of PCa cells, and further explore the potential regulatory mechanisms via regulating FOXC1. Methods: 60 pairs tumor specimens from PCa patients were collected to determine the expression level of miR-138-5p by qRT-PCR. Subsequently, over-expression of miR-138-5p were established to explore the proliferation and metastasis of miR-138-5p in PCa cell lines was analyzed by CCK-8, Tranwell assay and Wounding healing assay, respectively. Bioinformatics analysis and luciferase reporter gene assay were performed to search for the target genes of miR-138-5p, and FOXC1 was selected. Finally, the biological role of miR-138-5p and FOXC1 in the progression of PCa was clarified by a series of rescue experiments. Results: The results of qRT-PCR revealed that miR-138-5p was lowly expressed in PCa tissues and cell lines. Besdies, these PCa patients with low-miR-138-5p had a higher Gleason score, lymph node metastasis, bone metastasis and poor prognosis of PCa, compared with the patients with high-miR-138-5p. Over-expression of miR-138-5p inhibited the viability, migratory and invasive capacities of PC-3 and DU-145 cells. Bioinformatics analysis and luciferase reporter gene assay suggested that FOXC1 was predicted to be the target of miR-138-5p. Moreover, FOXC1 level was negatively correlated to that of miR-138-5p in PCa tissues. Importantly, FOXC1 could reverse miR-138-5p mimic induced-inhibition of PCa malignant progression. Conclusions: Downregulated miR-138-5p was closely associated with Gleason score, distant metastasis and poor prognosis of PCa patients. In addition, miR-138-5p alleviated the malignant progression of PCa by targeting and downregulating FOXC1.

miR-138-5p inhibits the metastasis of prostate cancer by targeting FOXC1

10.21203/rs.3.rs-16546/v2 ◽

2020 ◽

Author(s):

Dapeng Zhang ◽

Xiaodong Liu ◽

Qingwei Zhang ◽

Xin Chen

Keyword(s):

Cell Lines ◽

Bioinformatics Analysis ◽

Reporter Gene Assay ◽

Luciferase Reporter ◽

Over Expression ◽

Qrt Pcr ◽

Gene Assay ◽

Proliferation And Metastasis

Abstract Background: This study aimed to uncover the effect of miR-138-5p on the proliferation and metastasis of PCa cell lines, and further explore the potential regulatory mechanisms via regulating FOXC1.Methods: 60 pairs tumor tissues and corresponding paracancerous tissues from PCa patients were collected to determine the expression level of miR-138-5p by qRT-PCR. Subsequently, over-expression of miR-138-5p were established to explore the proliferation and metastasis of miR-138-5p in PCa cell lines was analyzed by CCK-8, Tranwell assay and Wounding healing assay, respectively. Bioinformatics analysis and luciferase reporter gene assay were performed to search for the target genes of miR-138-5p, and FOXC1 was selected. Finally, the biological role of miR-138-5p and FOXC1 in the progression of PCa was clarified by a series of rescue experiments. Results: The results of qRT-PCR revealed that miR-138-5p was lowly expressed in PCa tissues and cell lines. Besdies, these PCa patients with low-miR-138-5p had a higher Gleason score, lymph node metastasis and poor prognosis of PCa, compared with the patients with high-miR-138-5p. Over-expression of miR-138-5p inhibited the viability, migratory and invasive capacities of PC-3 and DU-145 cells. Bioinformatics analysis and luciferase reporter gene assay suggested that FOXC1 was predicted to be the target of miR-138-5p. Moreover, FOXC1 level was negatively correlated to that of miR-138-5p in PCa tissues. Importantly, FOXC1 could reverse miR-138-5p mimic induced-inhibition of PCa malignant progression.Conclusions: Downregulated miR-138-5p was closely associated with Gleason score, distant metastasis and poor prognosis of PCa patients. In addition, miR-138-5p alleviated the malignant progression of PCa by targeting and downregulating FOXC1.

Hsa-miR-105-1 Regulates Cisplatin-Resistance in Ovarian Carcinoma Cells by Targeting ANXA9

Analytical Cellular Pathology ◽

10.1155/2021/6662486 ◽

2021 ◽

Vol 2021 ◽

pp. 1-11

Author(s):

Xinxin Kou ◽

Hui Ding ◽

Lei Li ◽

Hongtu Chao

Keyword(s):

Ovarian Carcinoma ◽

Cell Lines ◽

Target Gene ◽

Molecular Mechanisms ◽

Cisplatin Resistance ◽

Luciferase Reporter ◽

Qrt Pcr ◽

Gene Assay ◽

Increased Sensitivity

Purpose. Cisplatin is one of the most effective drugs for treating ovarian carcinoma (OC), which is among the most lethal types of carcinoma. However, the chemoresistance to cisplatin that develops over time leads to a poor clinical outcome for many OC patients. Therefore, it is necessary to clearly understand the molecular mechanisms of chemoresistance. In this study, we examined how Hsa-miR-105-1 functions in cisplatin-resistant OC cells. Methods. The levels of Hsa-miR-105-1 expression in cisplatin-sensitive and resistant OC cell lines were detected by qRT-PCR. The target gene of Hsa-miR-105-1 was predicted by using the TargetScan and Starbase databases and verified by the double luciferase reporter gene assay. The target gene of Hsa-miR-105-1 was identified as ANXA9, and ANXA9 expression was evaluated by qRT-PCR, western blotting, and immunofluorescence. To validate the function of Hsa-miR-105-1 in OC cells, we silenced or overexpressed Hsa-miR-105-1 in cisplatin-sensitive or resistant OC cell lines, respectively. Furthermore, the expression levels of several apoptosis-related proteins, including P53, P21, E2F1, Bcl-2, Bax, and caspase-3, were examined by western blot analysis. Results. The levels of Hsa-miR-105-1 expression were abnormally downregulated in cisplatin-resistant OC cells, while ANXA9 expression was significantly upregulated in those cells. Treatment with an Hsa-miR-105-1 inhibitor promoted the expression of ANXA9 mRNA and protein, enhanced the resistance to cisplatin, and attenuated the cell apoptosis induced by cisplatin in cisplatin-sensitive OC cells. Moreover, treatment with Hsa-miR-105-1 mimics inhibited ANXA9 expression, which further increased the levels of P53, P21, and Bax expression and decreased the levels of E2F1 and Bcl-2 expression, finally resulting in an increased sensitivity to cisplatin in cisplatin-resistant OC cells. Conclusion. We found that a downregulation of Hsa-miR-105-1 expression enhanced cisplatin-resistance, while an upregulation of Hsa-miR-105-1 restored the sensitivity of OC cells to cisplatin. The Hsa-miR-105-1/ANXA9 axis plays an important role in the cisplatin-resistance of OC cells.

MiR-486 protects against acute myocardial infarction via regulation of PTEN

Tropical Journal of Pharmaceutical Research ◽

10.4314/tjpr.v20i9.10 ◽

2021 ◽

Vol 20 (9) ◽

pp. 1845-1853

Author(s):

Qinfeng Han ◽

Zhong Xu ◽

Xiaolei Zhang ◽

Kun Yang ◽

Zhifei Sun ◽

...

Keyword(s):

Myocardial Infarction ◽

Akt Signaling ◽

Reporter Gene Assay ◽

Expression Level ◽

Luciferase Reporter ◽

Akt Signaling Pathway ◽

Qrt Pcr ◽

Purpose: To investigate the effect of miR-486 on rats with acute myocardial infarction (AMI), and its mechanism of action.Methods: A rat model of AMI was established. They were randomly divided into 4 groups, namely, sham, model, agomiR-486 and antagomiR-486 groups, respectively. Rats in these different groups were treated with agomiR-21 (5 μL, 40 nmol/mL), antagomiR-21 (5 μL, 40 nmol/mL) or agomiR-NC (5 μL, 40 nmol/mL), respectively. Then, key miRNAs were sorted out using gene-chip assay and verified by quantitative reverse transcription polymerase chain reaction (qRT-PCR) assay. Luciferase reporter gene assay was conducted to determine the interaction between miR-486 and gene of PTEN. After intraperitoneal injection of agomiR-486 and antagomiR-486, hemodynamics was measured to determine the effect of miR-486 on myocardial function of the rats. The effect of miR-486 expression level on the expression of myocardial enzymes in serum, the morphology of myocardial tissues, and the apoptosis of myocardial tissues in rats, were investigated. Additionally, the effect of miR-486 expression level on PTEN/AKT signaling pathway in the rats was determined by Western blotting.Results: The results of gene-chip and qRT-PCR assays revealed that there were 8 differentially expressed genes in rat myocardial tissues in the model group when compared with the sham group. MiR-486 improved the cardiac function of rats and the morphology of myocardial tissues, but reduced AMI-induced apoptosis of myocardial cells and the expression of myocardial enzymes (markers of myocardial injury) in a dose-dependent manner (p < 0.05). The results of luciferase reporter gene assay showed that PTEN was a direct target of miR-486. In rat models of AMI, a raised expression of miR-486 remarkably suppressed the protein expression level of PTEN and up-regulated that of p-AKT/AKT (p < 0.05).Conclusion: MiR-486 protects against AMI in rats probably by targeting PTEN and activating the AKT signaling pathway. The results of the current study may provide new insights for the treatment of AMI.

PITPNA-AS1 Activated by H3K27ac Sponged miR-98-5p to Regulate Cisplatin Resistance in Gastric Cancer

10.21203/rs.3.rs-156344/v1 ◽

2021 ◽

Author(s):

Yaping Liu ◽

Xu Zhao ◽

Yinnan Chen ◽

Gang Guo ◽

Jiansheng Wang ◽

...

Keyword(s):

Gastric Cancer ◽

Cell Proliferation ◽

Molecular Mechanisms ◽

Luciferase Reporter ◽

Platinum Resistance ◽

Gene Assay ◽

Proliferation And Apoptosis ◽

Gastric Cancer Cell Lines ◽

Cancer Tissues

Abstract To evaluate the expression of PITPNA-AS1 and miR-98-5p in gastric cancer tissues as well as their association with progression of gastric cancer, and investigate the role of PITPNA-AS1 and miR-98-5p in developing platinum resistance. RNA sequencing was used to identify candidate lncRNAs and microRNAs related to local recurrence of gastric cancer. qRT-PCR was used to investigate the expression of PITPNA-AS1 and miR-98-5p. CCK-8 and caspase3/7 activity were used to evaluate the cell proliferation and apoptosis rate. Dual luciferase reporter gene assay and RNA pull down were used to evaluate the cross talk between PITPNA-AS1 and miR-98-5p. PITPNA-AS1 and miR-98-5p could regulate cell proliferation and inhibit apoptosis in gastric cancer cell lines. Cisplatin and lobaplatin could significantly suppress the expression of PITPNA-AS1, which interacted with negatively regulated miR-98-5p expression. PITPNA-AS1 overexpression impaired the effect of platinum, which was partially reversed by downregulation of miR-98-5p knock down. In gastric cancer, PITPNA-AS1 and miR-98-5p could regulat cell growth, apoptosis and platinum resistance. They have the potential to be biomarkers and curative therapeutic targets. However, further research on molecular mechanisms are needed.

[34] Luciferase reporter gene assay in mammalian cells

Methods in Enzymology - Recombinant DNA Part G ◽

10.1016/0076-6879(92)16036-j ◽

1992 ◽

pp. 386-397 ◽

Cited By ~ 26

Author(s):

Allan R. Brasier ◽

David Ron

Keyword(s):

Reporter Gene ◽

Mammalian Cells ◽

Reporter Gene Assay ◽

Luciferase Reporter ◽

Effect of miRNA-223-3p Targeting Stromal Interaction Molecule 1 on Proliferation and Apoptosis of Hypoxia/Reoxygenation-Applied H9c2 Cardiomyocytes

Journal of Biomaterials and Tissue Engineering ◽

10.1166/jbt.2021.2503 ◽

2021 ◽

Vol 11 (6) ◽

pp. 1066-1072

Author(s):

Bin Guang ◽

Xiaoqin Liu ◽

Tingchen Liang

Keyword(s):

Cell Activity ◽

Luciferase Reporter ◽

Cardiomyocyte Proliferation ◽

Gene Assay ◽

Proliferation And Apoptosis ◽

H9c2 Cardiomyocytes ◽

Cultured Cardiomyocytes ◽

Hypoxia Reoxygenation

This study was established to determine the effect of miRNA-223-3p on the proliferation and apoptosis of hypoxia/reoxygenation-applied H9c2 cardiomyocytes and the associated mechanisms. A hypoxia/reoxygenation (H/R) model was established, with normal cells also used as a control. miRNA-NC, miRNA-223-3p, anti-miRNA-NC, and anti-miRNA-223-3p plasmids were transfected into normally cultured cardiomyocytes, defined as the miRNA-NC, miRNA-223-3p, anti-miRNA-NC, and anti-miRNA-223-3p groups. In addition, miRNA-223-3p was co-transfected into normally cultured cardiomyocytes with pcDNA3.1 and pcDNA3.1-STIM1 plasmids, followed by treatment with H/R for cells in the miR-NC and miR-223-3p groups, defined as the H/R+miRNA-NC, H/R+miRNA-223-3p, H/R+miRNA-223-3p+pcDNA3.1, and H/R+miRNA-223-3p+pcDNA3.1-STIM1 groups. A liposome method was adopted for assessing transfection. qRT-PCR was used to detect miRNA-223-3p expression, while western blotting was used to detect protein expression. MTT assay was used to detect cell viability, flow cytometry to detect apoptosis, and dual luciferase reporter gene assay to detect fluorescence activity. After H/R treatment, miR-223-3p, cyclin D1, and Bcl-2 expression of cardiomyocytes decreased, p21 and Bax expression significantly increased, cell activity decreased, and the apoptosis rate increased. miRNA-223-3p achieved the targeted regulation of STIM1 expression. miRNA-223-3p overexpression promoted the H/R-induced cardiomyocyte proliferation and inhibited cardiomyocyte apoptosis. STIM1 overexpression reversed the proliferation-promoting and apoptosis-inhibiting effects of miRNA-223-3p on cardiomyocytes treated with H/R. The findings show that miRNA-223-3p overexpression promotes H/R-induced cell proliferation, inhibits apoptosis, and protects H/R-induced cardiomyocytes from injury, via a mechanism probably associated with STIM1 expression. miRNA-223-3p thus provides a new target for treating cardiomyocyte injury.