MiR-449b-5p Ameliorates Hypoxia-induced Cardiomyocyte Injury through Activating PI3K/AKT Pathway by Targeting BCL2L13.

Recent reports show miR-449b-5p reduces liver and renal ischemia/reperfusion (I/R) injury, but its effects on hypoxia-induced cardiomyocyte injury in ischemic heart disease are still unknown. In this study, AC16 human cardiomyocytes underwent hypoxic conditions for durations of 24, 48, and 72 h. We observed that miR-449b-5p expression was significantly downregulated in hypoxic AC16 cardiomyocytes. Elevating the levels of miR-449b-5p in these cells resulted in enhanced cell survival, diminished release of LDH, and a reduction in cell apoptosis and oxidative stress using CCK-8, LDH assays, flow cytometry, TUNEL staining, and various commercial kits. Conversely, reducing miR-449b-5p levels resulted in the opposite effects. Through bioinformatics analysis and luciferase reporter assays, BCL2-like 13 (BCL2L13) was determined to be a direct target of miR-449b-5p. Inhibiting BCL2L13 greatly inhibited hypoxia-induced cell viability loss, LDH release, cell apoptosis, and excessive production of oxidative stress, whereas increasing BCL2L13 negated miR-449b-5p's protective impact in hypoxic AC16 cardiomyocytes. Additionally, miR-449b-5p elevated the levels of the proteins p-PI3K, p-AKT, and Bcl-2, while decreasing Bax expression in hypoxic AC16 cardiomyocytes by targeting BCL2L13. In summary, the research indicates that the protective effects of miR-449b-5p are facilitated through the activation of the PI3K/AKT pathway, which promotes cell survival, and by targeting BCL2L13, which inhibits apoptosis, offering a potential therapeutic strategy for ischemic heart disease by mitigating hypoxia-induced cardiomyocyte injury.

Molecular Characterization and Expression Changes of the bcl2l13 Gene in Response to Hypoxia in Megalobrama amblycephala.

Hypoxia is a unique environmental stress, which not only reflects the insufficient oxygen supply of cells and tissues, but also occurs in various physiological and pathological environments. Mitophagy as a selective autophagy can recover and utilize damaged organelles and misfolded proteins to ensure normal cell functions and promote cell survival. Bcl2l13 (B-cell lymphoma-2 like 13) is reported to induce mitophagy as a functional mammalian homolog of Atg32. However, the function of the bcl2l13 gene is still unclear in fish. Here the sequence and structure of the bcl2l13 gene in Megalobrama amblycephala were identified and showed that bcl2l13 contained an open reading frame (ORF) of 1458 bp for encoding 485 aa. Amino acid sequence analysis indicated that Bcl2l13, as a typical anti-apoptotic protein of the Bcl2 family, contained four BH domains, one BHNo domain, and one TM domain. Further study showed that Bcl2l13 was mainly located in the mitochondria, while its localization was changed within the whole cell after the TM domain was deleted. Real-time PCR analysis revealed that bcl2l13 showed higher expression levels in early embryos. After hypoxia treatment, the mRNA levels of the bcl2l13 and autophagy-related genes were significantly up-regulated in most detected tissues, and the bcl2l13 transcription was regulated by Hif-1α mediated pathway. Additionally, the transcription activity of the bcl2l13 promoter was further analyzed using luciferase reporter assays and showed the highest activity in the promoter region from -475 to +111. These results indicated that bcl2l13 may play important roles in embryogenesis and hypoxia mediated autophagy in fish.

Significant role of circRNA BBS9 in chronic obstructive pulmonary disease via miRNA-103a-3p/BCL2L13.

BACKGROUND: Various studies have shown that circular RNA (circRNA) plays a pivotal role in chronic obstructive pulmonary disease (COPD). We aimed to determine the role of circRNA BBS9 in COPD progression. METHODS: Real-time quantitative reverse transcription PCR (qRT-PCR) was performed to determine the levels and the linkages of circRNA BBS9, miRNA-103a-3p, and BCL2L13 in cigarette smoke extract (CSE)-treated human pulmonary microvascular endothelial cells (HPMECs). The target binding sites of circRNA BBS9 and miRNA-103a-3p were predicted using the starBase database, and the TargetScan algorithm was used to forecast the potential binding sites of BCL2L13 and miRNA-103a-3p, which were verified using a dual-luciferase reporter assay. An flow cytometry (FCM) assay was performed to determine the rate of apoptosis of HPMECs. Caspase3 activity was determined using a Caspase3 assay kit. The apoptosis-related protein bands were determined by western blotting. RESULTS: The level of circRNA BBS9 increased in 1% CSE-induced cells, and silencing of circRNA BBS9 decreased the ratio of apoptotic cells among the 1% CSE-induced HPMECs. The results of dual-luciferase reporter assays showed that miRNA-103a-3p associates with circRNA BBS9. miRNA-103a-3p was downregulated in COPD, and upregulation of miRNA-103a-3p inhibited apoptosis in CSE-stimulated cells. Moreover, BCL2L13 was found to act downstream of miRNA-103a-3p. Silencing of miRNA-103a-3p reversed the inhibitory effect of circRNA BBS9-siRNA. The effects of the miRNA-103a-3p mimic were reversed by the BCL2L13-plasmid. CONCLUSION: circRNA BBS9 is involved in COPD development as it inhibits the functioning of miRNA-103a-3p. Our results suggest that circRNA BBS9 may act as a novel target for treating COPD.

Small Peptides from Periplaneta americana Inhibits Oxidative Stress-Induced KGN Cell Apoptosis by Regulating Mitochondrial Function Through Bcl2L13.

This study examined the protective effects of small peptides from Periplaneta americana against H2O2-induced mitochondrial injury in human ovarian granulosa cells. The ATP level and mitochondrial membrane potential as well as the quantity and ultrastructure of mitochondria in cells were detected. Mitochondrial DNA copy number and expression levels of Bcl2L13, LC3B, and p62 were tested. Targeted silencing of Bcl2L13 expression in KGN cells. The expression levels of Bcl2L13 and LC3B as well as interaction were evaluated. The ATP level, mtDNA-CN, and MMP of the H2O2 group were significantly lower than those of the normal control group (P < 0.05), accompanied by a reduction in mitochondrial mass and mitochondrial fluorescence intensity (P < 0.05). However, the ATP level, mtDNA, and MMP in KGN cells were increased after SPPA treatment (P < 0.05). Scanning electron microscopy shows that SPPA ameliorates H2O2-induced structural damage to mitochondria. Moreover, the expression levels of Bcl2L13 and p62 in the H2O2 group were downregulated significantly compared with those of the normal control group (P < 0.05), while LC3B was upregulated (P < 0.05). After SPPA treatment, the expression levels of Bcl2L13 and p62 were upregulated (P < 0.05), while LC3B was downregulated (P < 0.05). The Co-IP results indicated that Bcl2L13 and LC3B interacted, and this interaction was weakened after cell treatment with H2O2, and dissociation between Bcl2L13 and LC3B declined after SPPA treatment. SPPA inhibits KGN cell apoptosis induced by oxidative stress via inhibition of mitochondrial injury Bcl2L13-mediated mitochondrial autophagy might participate in the regulation process.

The protective effect of inhibiting mitochondrial fission on the juvenile rat brain following PTZ kindling through inhibiting the BCL2L13/LC3 mitophagy pathway.

Maintaining the balance of mitochondrial fission and mitochondrial autophagy on seizures is helpful to find a solution to control seizures and reduce brain injuries. The present study is to investigate the protective effect of inhibiting mitochondrial fission on brain injury in juvenile rat epilepsy induced by pentatetrazol (PTZ) by inhibiting the BCL2L13/LC3-mediated mitophagy pathway. PTZ was injected (40 mg/kg) to induce kindling once every other day, for a total of 15 times. In the PTZ + DMSO (DMSO), PTZ + Mdivi-1 (Mdivi-1), and PTZ + WY14643 (WY14643) groups, rats were pretreated with DMSO, Mdivi-1 and WY14643 for half an hour prior to PTZ injection. The seizure attacks of young rats were observed for 30 min after model establishment. The Morris water maze (MWM) was used to test the cognition of experimental rats. After the test, the numbers of NeuN(+) neurons and GFAP(+) astrocytes were observed and counted by immunofluorescence (IF). The protein expression levels of Drp1, BCL2L13, LC3 and caspase 3 in the hippocampus of young rats were detected by immunohistochemistry (IHC) and Western blotting (WB). Compared with the PTZ and DMSO groups, the seizure latency in the Mdivi-1 group was longer (P < 0.01), and the severity degree and frequency of seizures were lower (P < 0.01). The MWM test showed that the incubation periods of crossing the platform in the Mdivi-1 group was significantly shorter. The number of platform crossings, the platform stay time, and the ratio of residence time/total stay time were significantly increased in the Mdivi-1 group (P < 0.01). The IF results showed that the number of NeuN(+) neurons in the Mdivi-1 group was greater, while the number of GFAP(+) astrocytes was lower. IHC and WB showed that the average optical density (AOD) and relative protein expression levels of Drp1, BCL2L13, LC3 and caspase 3 in the hippocampi of rats in the Mdivi-1 group were higher (P < 0.05). The above results in the WY14643 group were opposite to those in the Mdivi-1 group. Inhibition of mitochondrial fission could reduce seizure attacks, protect injured neurons, and improve cognition following PTZ-induced epilepsy by inhibiting mitochondrial autophagy mediated by the BCL2L13/LC3 mitophagy pathway.

PGAM5 interacts with Bcl-rambo and regulates apoptosis and mitophagy.

Bcl-rambo, also known as BCL2L13, has been reported to regulate apoptosis, mitochondrial fragmentation, and mitophagy. However, the molecular mechanisms by which Bcl-rambo regulates these processes currently remain unclear. In the present study, we identified phosphoglycerate mutase member 5 (PGAM5) as an emerging partner interacting with Bcl-rambo through phenotypic Drosophila screening. The rough eye phenotype induced by human Bcl-rambo was partly rescued by the knockdown of pgam5-2, a mammalian ortholog of PGAM5. Bcl-rambo bound to PGAM5, and their interaction required the Bcl-rambo transmembrane domain. The co-expression of Bcl-rambo and PGAM5 promoted effector caspase activity in human embryonic kidney 293T cells. The transient overexpression of Bcl-rambo increased LC3B-II levels, which had been decreased by the co-expression of PGAM5. These results suggest that PGAM5 promotes Bcl-rambo-dependent apoptosis, but conversely interferes with Bcl-rambo-dependent mitophagy.

LncRNA SNHG14 is beneficial to oxygen glucose deprivation/reoxygenation-induced neuro-2a cell injury via mir-98-5p sequestration-caused BCL2L13 upregulation.

BACKGROUND: The deregulation of long non-coding RNA (lncRNA) is associated with diverse human disorders, including cerebral ischemia/reperfusion injury (CI/RI). LncRNA SNHG14 was reported to function in CI/RI. Whereas, molecular mechanisms regulated by SNHG14 are not fully unveiled. METHODS: Mice subjected to middle cerebral artery occlusion/reperfusion (MCAO/R) were used as CI/RI animal models. Neuro-2a (N2A) cells subjected to oxygen glucose deprivation/reoxygenation (OGD/R) were used as CI/RI cell models. The expression of SNHG14, miR-98-5p and BCL2 like 13 (BCL2L13) was examined using quantitative real-time PCR (qPCR) or western blot. Apoptosis was monitored by flow cytometry assay. Apoptosis-related markers and endoplasmic reticulum (ER) stress-related markers were quantified by western blot. Inflammatory factors and oxidative stress were detected using matched commercial kits. The predicted relationship between miR-98-5p and SNHG14 or BCL2L13 was validated by dual-luciferase reporter assay, RIP assay and pull-down assay. RESULTS: The high expression of SNHG14 was monitored in MCAO/R-treated mice and OGD/R-treated N2A cells. OGD/R-induced N2A cell apoptosis, ER stress, inflammation and oxidative stress were attenuated by SNHG14 knockdown. SNHG14 targeted miR-98-5p to positively regulate BCL2L13 expression. Inhibition of miR-98-5p recovered cell apoptosis, ER stress, inflammation and oxidative stress that were repressed by SNHG14 knockdown. Overexpression of BCL2L13 enhanced cell apoptosis, ER stress, inflammation and oxidative stress that were repressed by miR-98-5p enrichment. CONCLUSIONS: SNHG14 knockdown alleviated OGD/induced N2A cell apoptosis, ER stress, inflammation and oxidative stress by depleting BCL2L13 via increasing miR-98-5p.

Therapeutic regulation of autophagy in hepatic metabolism.

Metabolic homeostasis requires dynamic catabolic and anabolic processes. Autophagy, an intracellular lysosomal degradative pathway, can rewire cellular metabolism linking catabolic to anabolic processes and thus sustain homeostasis. This is especially relevant in the liver, a key metabolic organ that governs body energy metabolism. Autophagy's role in hepatic energy regulation has just begun to emerge and autophagy seems to have a much broader impact than what has been appreciated in the field. Though classically known for selective or bulk degradation of cellular components or energy-dense macromolecules, emerging evidence indicates autophagy selectively regulates various signaling proteins to directly impact the expression levels of metabolic enzymes or their upstream regulators. Hence, we review three specific mechanisms by which autophagy can regulate metabolism: A) nutrient regeneration, B) quality control of organelles, and C) signaling protein regulation. The plasticity of the autophagic function is unraveling a new therapeutic approach. Thus, we will also discuss the potential translation of promising preclinical data on autophagy modulation into therapeutic strategies that can be used in the clinic to treat common metabolic disorders.

Biological properties of the BCL-2 family protein BCL-RAMBO, which regulates apoptosis, mitochondrial fragmentation, and mitophagy.

Mitochondria play an essential role in the regulation of cellular stress responses, including cell death. Damaged mitochondria are removed by fission and fusion cycles and mitophagy, which counteract cell death. BCL-2 family proteins possess one to four BCL-2 homology domains and regulate apoptosis signaling at mitochondria. BCL-RAMBO, also known as BCL2-like 13 (BCL2L13), was initially identified as one of the BCL-2 family proteins inducing apoptosis. Mitophagy receptors recruit the ATG8 family proteins MAP1LC3/GABARAP via the MAP1LC3-interacting region (LIR) motif to initiate mitophagy. In addition to apoptosis, BCL-RAMBO has recently been identified as a mitophagy receptor that possesses the LIR motif and regulates mitochondrial fragmentation and mitophagy. In the 20 years since its discovery, many important findings on BCL-RAMBO have been increasingly reported. The biological properties of BCL-RAMBO are reviewed herein.

Circ_0062166 aggravates cerebral ischemia-reperfusion injury through targeting miR-526b-5p/BCL2L13 axis.

BACKGROUND: Cerebral ischemia-reperfusion (CIR) injury is a severe disease, which may cause serious dysfunction of the brain. Most circular RNAs (circRNAs) have been demonstrated to play a significant role in CIR injury. However, a novel circRNA, circ_0062166 (circ_BCL2L13) has not been investigated for CIR injury. Hence, we aim to disclose the role of circ_0062166 in CIR injury in this study. METHODS: Firstly, RT-qPCR was applied to examine the expression of circ_0062166 in oxygen-glucose deprivation and reoxygenation (OGD/R) cell model. Functional assays were conducted to detect the role of circ_0062166 in CIR injury. RNA pull down, RIP and luciferase reporter assays were implemented to probe into the regulatory mechanism of circ_0062166. RESULTS: Circ_0062166 was significantly up-regulated in neuro-2A (N2A) neuroblastoma cells following OGD/R. Functionally, the silencing of circ_0062166 inhibited cell proliferation and promoted cell apoptosis under OGD/R condition. From the perspective of mechanism, circ_0062166 functioned as a competing endogenous RNA (ceRNA) for microRNA-526b-5p (miR-526b-5p) and regulated BCL2 like 13 (BCL2L13). Eventually, the promoting role of the circ_0062166/miR-526b-5p/BCL2L13 axis in the CIR injury was verified. CONCLUSION: To sum up, the present study has demonstrated that circ_0062166/miR-526b-5p/BCL2L13 axis accelerated the progression of CIR injury, which might provide effective strategies for CIR injury therapy.

Silencing of H19 alleviates oxygen-glucose deprivation/reoxygenation-triggered injury through the regulation of the miR-1306-5p/BCL2L13 axis.

Cerebral ischemia/reperfusion (I/R) injury remains a leading cause of death and disability. Long noncoding RNAs (lncRNAs) exert key functions in cerebral I/R injury. Here, we sought to elucidate the mechanism underlying the regulation of H19 in cerebral I/R cell injury. An in vitro model of cerebral I/R injury was created using oxygen-glucose deprivation/reoxygenation (OGD/R). The levels of H19, miR-1306-5p and B cell lymphoma-2 (Bcl-2)-like 13 (BCL2L13) were assessed by quantitative real-time polymerase chain reaction (qRT-PCR) or western blot. Cell viability and apoptosis were determined by the Cell Counting-8 Kit (CCK-8) assay and flow cytometry, respectively. The levels of lactate dehydrogenase (LDH) and cytokines were evaluated by enzyme-linked immunosorbent assays (ELISA). Direct relationships among H19, miR-1306-5p and BCL2L13 were verified by dual-luciferase reporter, RNA immunoprecipitation (RIP) and RNA pulldown assays. Our data showed that H19 and BCL2L13 were highly expressed in the cerebral I/R injury rats and OGD/R-triggered SK-N-SH and IMR-32 cells. The knockdown of H19 or BLC2L13 alleviated OGD/R-triggered injury in SK-N-SH and IMR-32 cells. Moreover, H19 silencing protected against OGD/R-triggered cell injury by down-regulating BCL2L13. H19 acted as a sponge of miR-1306-5p and BCL2L13 was a direct target of miR-1306-5p. H19 mediated BCL2L13 expression by sequestering miR-1306-5p. Furthermore, miR-1306-5p was a molecular mediator of H19 function. These results suggested that H19 silencing alleviated OGD/R-triggered I/R injury at least partially depending on the regulation of the miR-1306-5p/BCL2L13 axis.

Deficit of female sex hormones desensitizes rat cardiac mitophagy.

Long-term deprivation of female sex hormones has been shown to mediate accumulation of damaged mitochondria in ventricular muscle leading to cardiovascular dysfunction. Therefore, the roles of female sex hormones in mitochondrial quality control are closely focused. In the present study, depletion of female sex hormones impairing mitochondrial autophagy in the heart was hypothesized. Cardiac mitophagy was therefore investigated in the heart of 10-week ovariectomized (OVX) and sham-operated (SHAM) rats. By using isolated mitochondria preparation, results demonstrated an increase in mitochondrial PTEN-induced kinase 1 accumulation in the sample of OVX rats indicating mitochondrial outer membrane dysfunction. However, no change in p62 and LC3-II translocation to mitochondria was observed between two groups indicating unresponsiveness of mitophagosome formation in the OVX rat heart. This loss might be resulted from significant decreases in Parkin and Bcl2l13 expression, but not Bnip3 activation. In summary, results suggest that mitochondrial abnormality in the heart after deprivation of female sex hormones could consequently be due to desensitization of mitophagy process.

By targeting apoptosis facilitator BCL2L13, microRNA miR-484 alleviates cerebral ischemia/reperfusion injury-induced neuronal apoptosis in mice.

Neuronal apoptosis was considered as one of the main factors of cerebral ischemia/reperfusion injury. Understanding the molecular regulatory mechanism of neuronal apoptosis under the cerebral ischemia/reperfusion injury may provide the novel therapeutic targets for cerebral ischemia/reperfusion injury. However, the molecular regulatory mechanism of neurons fate determination under the cerebral ischemia/reperfusion injury remains poorly understood. This study was aimed to delve into the related molecular mechanism of miR-484 on the regulation of cerebral ischemia/reperfusion injury-induced neuronal apoptosis in mice. In this study, quantitative real-time polymerase chain reaction assays revealed that the expression level of miR-484 was down-regulated in neurons following OGD. Then, CCK8 assay western blot assay, and flow cytometry assay verified that upregulation of miR-484 increased viability and inhibited apoptosis of neurons following OGD. Further bioinformatics methods and dual-luciferase reporter assay were applied together to anticipate and certify the interaction between miR-484 and BCL2L13. Finally, cerebral infarct size assessment and TUNEL staining confirmed that overexpression of miR-484 alleviated cerebral ischemia/reperfusion injury in mice, and overexpression of BCL2L13 could abolish the effect of miR-484-suppressed cell apoptosis. All these results suggested that miR-484 alleviates cerebral ischemia/reperfusion injury-induced neuronal apoptosis in mice by targeting apoptosis facilitator BCL2L13.

Mitophagy in tumorigenesis and metastasis.

Cells use mitophagy to remove dysfunctional or excess mitochondria, frequently in response to imposed stresses, such as hypoxia and nutrient deprivation. Mitochondrial cargo receptors (MCR) induced by these stresses target mitochondria to autophagosomes through interaction with members of the LC3/GABARAP family. There are a growing number of these MCRs, including BNIP3, BNIP3L, FUNDC1, Bcl2-L-13, FKBP8, Prohibitin-2, and others, in addition to mitochondrial protein targets of PINK1/Parkin phospho-ubiquitination. There is also an emerging link between mitochondrial lipid signaling and mitophagy where ceramide, sphingosine-1-phosphate, and cardiolipin have all been shown to promote mitophagy. Here, we review the upstream signaling mechanisms that regulate mitophagy, including components of the mitochondrial fission machinery, AMPK, ATF4, FoxOs, Sirtuins, and mtDNA release, and address the significance of these pathways for stress responses in tumorigenesis and metastasis. In particular, we focus on how mitophagy modulators intersect with cell cycle control and survival pathways in cancer, including following ECM detachment and during cell migration and metastasis. Finally, we interrogate how mitophagy affects tissue atrophy during cancer cachexia and therapy responses in the clinic.

LncRNA FOXD3-AS1 knockdown protects against cerebral ischemia/reperfusion injury via miR-765/BCL2L13 axis.

AIMS: Long non-coding RNAs (lncRNAs) FOXD3-AS1 was reported to be increased in cardiomyocyte ischemic injury. However, its role and underlying molecular mechanism in ischemic stroke remain unknown. This study was to investigate the role of FOXD3-AS1 in cerebral ischemia/reperfusion injury. METHODS: The expression of FOXD3-AS1 and miR-765 were measured with qRT-PCR. The shared putative miR-765 binding sites both in BCL2L13 and FOXD3-AS1 were identified with bioinformatics, luciferase reporter assay and RNA immunoprecipitation. Apoptosis and its related proteins were detected by TUNEL assay, Hoechst 33,258 staining, flow cytometry and western blot. Infarct volume and the neurological status were evaluated with TTC staining and neurologic deficit score, respectively. RESULTS: The up-regulation of FOXD3-AS1 and down-regulation of miR-765 were found in both mouse brains after cerebral ischemia/reperfusion (I/R) and neuroblastoma cells of neuro-2A (N2a) after oxygen-glucose deprivation/reoxygenation (OGD/R). Moreover, the overexpression of miR-765 reduced N2a cell apoptosis caused by OGD/R. MiR-765 could target BCL2L13 directly. In addition, we found that FOXD3-AS1 bound to miR-765 directly, acting as a ceRNA to modulate the expression of BCL2L13. Overexpression of FOXD3-AS1 antagonized the inhibitory impact of miR-765 on the expression of BCL2L13 and the apoptosis of N2a cells treated with OGD/R, while FOXD3-AS1 knockdown promoted the inhibitory impact of miR-765 on the expression of BCL2L13 and the apoptosis of N2a cells treated with OGD/R. Furthermore, we found that neurological deficits and brain injury induced by I/R in vivo were attenuated by FOXD3-AS1 knockdown. CONCLUSIONS: We verified a critical signaling pathway of FOXD3-AS1/miR-765/BCL2L13 in regulating cerebral ischemia/reperfusion injury.

Long non-coding RNA SNHG15 is a competing endogenous RNA of miR-141-3p that prevents osteoarthritis progression by upregulating BCL2L13 expression.

Increasing evidence has demonstrated that the dysregulated expression of long noncoding RNAs (lncRNAs) has important roles in the progression of osteoarthritis (OA), but the function of the lncRNA SNHG15 remains unclear. In the present study, we observed that SNHG15 was downregulated in OA cartilage tissues and IL-1ß-induced chondrocytes. The lower expression of SNHG15 was negatively associated with the observed modified Mankin scale scores, extracellular matrix (ECM) degradation and chondrocyte apoptosis. Downregulated expression of SNHG15 increased chondrocyte viability and decreased chondrocyte apoptosis and ECM degradation in vitro and reduced damage to articular cartilage in vivo. Mechanistically, we demonstrated that SNHG15 overexpression promotes the expression of BCL2L13 by sponging miR-141-3p. The higher expression of miR-141-3p was negatively correlated with SNHG15 and BCL2L13 levels in OA cartilage tissues, and a positive correlation was also shown between SNHG15 and BCL2L13 levels. Furthermore, ectopic expression of miR-141-3p or knockdown of BCL2L13 expression could both reduce the effects of SNHG15 on chondrocyte proliferation, apoptosis and ECM degradation. Collectively, these findings reveal that SNHG15 inhibits OA progression by acting as an miR-141-3p sponge to promote BCL2L13 expression, suggesting that knockdown of SNHG15 expression in chondrocytes can be a potential therapeutic strategy to ameliorate OA progression.

The mitophagy receptor Bcl-2-like protein 13 stimulates adipogenesis by regulating mitochondrial oxidative phosphorylation and apoptosis in mice.

Metabolic programming of bone marrow stromal cells (BMSCs) could influence the function of progenitor osteoblasts or adipocytes and hence determine skeletal phenotypes. Adipocytes predominantly utilize oxidative phosphorylation, whereas osteoblasts use glycolysis to meet ATP demand. Here, we compared progenitor differentiation from the marrow of two inbred mouse strains, C3H/HeJ (C3H) and C57BL6J (B6). These strains differ in both skeletal mass and bone marrow adiposity. We hypothesized that genetic regulation of metabolic programs controls skeletal stem cell fate. Our experiments identified Bcl-2-like protein 13 (Bcl2l13), a mitochondrial mitophagy receptor, as being critical for adipogenic differentiation. We also found that Bcl2l13 is differentially expressed in the two mouse strains, with C3H adipocyte progenitor differentiation being accompanied by a >2-fold increase in Bcl2l13 levels relative to B6 marrow adipocytes. Bcl2l13 expression also increased during adipogenic differentiation in mouse ear mesenchymal stem cells (eMSCs) and the murine preadipocyte cell line 3T3-L1. The higher Bcl2l13 expression correlated with increased mitochondrial fusion and biogenesis. Importantly, Bcl2l13 knockdown significantly impaired adipocyte differentiation in both 3T3-L1 cells and eMSCs. Mechanistically, Bcl2l13 knockdown reprogrammed cells to rely more on glycolysis to meet ATP demand in the face of impaired oxidative phosphorylation. Bcl2l13 knockdown in eMSCs increased mitophagy. Moreover, Bcl2l13 prevented apoptosis during adipogenesis. Our findings indicate that the mitochondrial receptor Bcl2l13 promotes adipogenesis by increasing oxidative phosphorylation, suppressing apoptosis, and providing mitochondrial quality control through mitophagy. We conclude that genetic programming of metabolism may be important for lineage determination and cell function within the bone marrow.

Upregulation of miR-874-3p decreases cerebral ischemia/reperfusion injury by directly targeting BMF and BCL2L13.

Ischemic stroke represents a major cause of adult physical disability, which is triggered by cerebral artery occlusion induced blood flow blockage. MiR-874-3p has been reported to be down-regulated in the brain injury induced by ischemia-reperfusion (I/R), but the direct evidence associated with injury of I/R remains unknown. In this study, we found that miR-874-3p levels significantly decreased in rat I/R brain induced by middle cerebral artery occlusion/reperfusion (MCAO/R) and SH-SY5Y cells following oxygen-glucose deprivation and reperfusion (OGD/R) treatment. Upregulation of miR-874-3p reduced infarct volumes and cell apoptosis in the in vivo I/R stroke model using TTC and TUNEL staining, as well as increased proliferation and inhibited apoptosis in OGD/R induced SH-SY5Y cells by CCK-8, Edu staining and flow cytometry analysis. Mechanistically, bioinformatics analysis and luciferase reporter assay confirmed BCL-2-modifying factor (BMF) and Bcl-2 family protein Bcl-rambo (BCL2L13) were the direct targets of miR-874-3p. Furthermore, BMF or BCL2L13 knockdown also provided significant protection against OGD/R induced injury, while their overexpression reversed the protective effects of miR-874-3p on SH-SY5Y cells following OGD/R. In summary, our results suggest that miR-874-3p attenuated ischemic injury by negatively regulating BMF and BCL2L13, highlighting a novel therapeutic target for ischemic stroke.

A Mammalian Mitophagy Receptor, Bcl2-L-13, Recruits the ULK1 Complex to Induce Mitophagy.

Degradation of mitochondria by selective autophagy, termed mitophagy, contributes to the control of mitochondrial quality. Bcl2-L-13 is a mammalian homolog of Atg32, which is an essential mitophagy receptor in yeast. However, the molecular machinery involved in Bcl2-L-13-mediated mitophagy remains to be elucidated. Here, we show that the ULK1 (unc-51-like kinase) complex is required for Bcl2-L-13 to process mitophagy. Screening of a series of yeast Atg mutants revealed that a different set of ATG genes is used for Bcl2-L-13- and Atg32-mediated mitophagy in yeast. The components of the Atg1 complex essential for starvation-induced autophagy were indispensable in Bcl2-L-13-, but not Atg32-mediated, mitophagy. The ULK1 complex, a counterpart of the Atg1 complex, is necessary for Bcl2-L-13-mediated mitophagy in mammalian cells. We propose a model where, upon mitophagy induction, Bcl2-L-13 recruits the ULK1 complex to process mitophagy and the interaction of LC3B with ULK1, as well as Bcl2-L-13, is important for the mitophagy.

A novel role for Bcl2l13 in promoting beige adipocyte biogenesis.

Bcl2l13 is a member of the Bcl-2 family that has been found to play a central role in regulating apoptosis. Recently Bcl2l13 has been reported to induce mitophagy as a functional mammalian homolog of Atg32. However, the role of Bcl2l13 in adipose tissue has not been investigated yet. In the present study, we found that Bcl2l13 expression was increased in white adipose tissue browning process stimulated by cold exposure or ß3-adrenergic agonist CL-316,243 in vivo as well as during brown adipocytes differentiation in vitro. Moreover, Bcl2l13 disruption dramatically inhibited the browning program of preadipocytes, evidenced by reduced Prdm16, Ucp1, Dio2 and Adrb3 expression. Our findings revealed that the inhibition effect of Bcl2l13 disruption on browning program may be independent of altering autophagy activity, but through regulating mitochondrial dynamic and biogenesis, supported by decreased mitochondrial fission/fussion genes, PGC-1α and mitochondrial respiratory chain complexes expression. Taken together, our study uncovered a novel function of Bcl2l13 in adipocytes differentiation and promoting browning program.