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Background: Apoptosis is an important pathologic mechanism of erectile dysfunction after radical prostatectomy. Studies have shown that programmed cell death factor 4 is connected to the modulation of apoptosis in many cells. However, the programmed cell death factor 4 function in the cavernous nerve injury erectile dysfunction is unclear. Objective: This investigation aimed to explore the programmed cell death factor 4 function in erectile dysfunction in rats with bilateral cavernous nerve crush. Materials and methods: The experiment used 30 male Sprague Dawley rats (18 months old) that were screened for normal erectile function by the apomorphine test. Ten rats were randomized into Sham and bilateral cavernous nerve crush groups to detect changes in programmed cell death factor 4 expression. The remaining 20 rats were distributed at random to four groups: the Sham group treated by sham surgery, the phosphate‐buffered saline group, the lentivirus containing negative control short hairpin RNA group, and the lentivirus containing short hairpin RNA targeting programmed cell death factor 4 group underwent bilateral cavernous nerve crush and were afterward administered intracavernous injections of phosphate‐buffered saline, lentivirus containing negative control short hairpin RNA, or lentivirus containing short hairpin RNA targeting programmed cell death factor 4. Electrical stimulation of the cavernous nerve was conducted 2 weeks later for penile erectile function assessment. The cavernous tissue was collected for histological analysis and western blotting. Results: The apoptosis level in rat corpus cavernosum was elevated, and programmed cell death factor 4 expression was increased after bilateral cavernous nerve crush. Knockdown of programmed cell death factor 4 significantly improved erectile function in bilateral cavernous nerve crush rats. Furthermore, lentivirus containing short hairpin RNA targeting programmed cell death factor 4 treatment raised smooth muscle content and attenuated cavernous fibrosis and apoptotic levels. Additionally, programmed cell death factor 4 was found to mediate the PI3K/AKT pathway. Discussion and conclusion: Elevated programmed cell death factor 4 expression may be an important pathogenetic mechanism for erectile dysfunction after bilateral cavernous nerve crush, and the knockdown of programmed cell death factor 4 enhanced erectile function in 18‐month‐old rats after cavernous nerve damage. The potential mechanism may be the stimulation of the PI3K/AKT pathway to attenuate the cavernous apoptosis level. [ABSTRACT FROM AUTHOR]

BACKGROUND: Circular RNAs (circRNAs) are the emerging informative RNAs, involved in cardiovascular diseases including atherosclerosis (AS). Endothelial injury is the initial qualitative change of AS. Thus, the objective of this study was to confirm the dysregulation and mechanism of circ_0000231 in cell model of AS at early stage in human umbilical vein endothelial cells (HUVECs) induced by oxidized low-density lipoprotein (ox-LDL). METHODS: The expression of circ_0000231, miR-590-5p and programmed cell death 4 (PDCD4) was detected using real-time quantitative PCR and western blot. Cell injury was measured with MTT, flow cytometry, caspase-3 activity assay and enzyme-linked immunosorbent assay (ELISA). The interaction among circ_0000231, miR-590-5p and PDCD4 was validated by dual-luciferase reporter assay, RNA immunoprecipitation (RIP) and pull-down assays. RESULTS: Stress ox-LDL decreased cell viability, and increased apoptosis rate and caspase-3 activity in HUVECs in a dose- and time-dependent manner in concomitant with promotions of interleukin-6, interleukin-1β, tumor necrosis factor-α, LC3-II/I and Beclin-1 levels. Besides, circ_0000231 and PDCD4 expressions were upregulated, and miR-590-5p was downregulated in ox-LDL-stimulated HUVECs. Functionally, knockdown of circ_0000231 and overexpression of miR-590-5p could suppress ox-LDL-elicited above effects on apoptosis, autophagy and inflammatory response, accompanied with PDCD4 downregulation. Physically, miR-590-5p could directly interact with circ_0000231 and PDCD4. CONCLUSION: Downregulation of circ_0000231 suppresses HUVECs from ox-LDL-induced injury partially through regulating miR-590-5p/PDCD4 axis via competing endogenous RNA mechanism, showing a novel potential target for the pathology and treatment of endothelial injury in AS. [ABSTRACT FROM AUTHOR]

As obligate parasites, viruses have evolved multiple strategies to evade the host immune defense. Manipulation of the host proteasome system to degrade specific detrimental factors is a common viral countermeasure. To identify host proteins targeted for proteasomal degradation by porcine reproductive and respiratory syndrome virus (PRRSV), we conducted a quantitative proteomics screen of PRRSV-infected Marc-145 cells under the treatment with proteasome inhibitor MG132. The data revealed that the expression levels of programmed cell death 4 (PDCD4) were strongly downregulated by PRRSV and significantly rescued by MG132. Further investigation confirmed that PRRSV infection induced the translocation of PDCD4 from the nucleus to the cytoplasm, and the viral nonstructural protein 9 (Nsp9) promoted PDCD4 proteasomal degradation in the cytoplasm by activating the Akt-mTOR-S6K1 pathway. The C-terminal domain of Nsp9 was responsible for PDCD4 degradation. As for the role of PDCD4 during PRRSV infection, we demonstrated that PDCD4 knockdown favored viral replication, while its overexpression significantly attenuated replication, suggesting that PDCD4 acts as a restriction factor for PRRSV. Mechanistically, we discovered eukaryotic translation initiation factor 4A (eIF4A) was required for PRRSV. PDCD4 interacted with eIF4A through four sites (E249, D253, D414, and D418) within its two MA3 domains, disrupting eIF4A-mediated translation initiation in the 5-untranslated region of PRRSV, thereby inhibiting PRRSV infection. Together, our study reveals the antiviral function of PDCD4 and the viral strategy to antagonize PDCD4. These results will contribute to our understanding of the immune evasion strategies employed by PRRSV and offer valuable insights for developing new antiviral targets. [ABSTRACT FROM AUTHOR]

To explore the potential mechanism of microRNA (miR)-181b-5p promoting the progression of thyroid cancer (TC) by targeting programmed cell death 4 (PDCD4). Analysis of miR-181b-5p and PDCD4 expression in TC was performed. The impact of miR-181b-5p and PDCD4 on proliferation, migration, invasion, and apoptosis of TC cells was examined. The binding relationship between miR-181b-5p and PDCD4 was predicted and verified. miR-181b-5p was up-regulated in TC, while PDCD4 was down-regulated. Down-regulating miR-181b-5p or up-regulating PDCD4 inhibited the proliferation, migration, and invasion of TC cells, and promoted cell apoptosis. PDCD4 was the downstream target of miR-181b-5p, and down-regulation of PDCD4 counteracted the inhibitory effect of down-regulation of miR-181b-5p on the proliferation, migration, and invasion of TC cells and the promoting effect on apoptosis. miR-181b-5p inhibits the proliferation, migration, and invasion of TC cells and promotes cell apoptosis by targeting PDCD4. [ABSTRACT FROM AUTHOR]

Objectives: Celastrus orbiculatus ethyl acetate extract (COE) is the main extract of the stem of the Chinese herbal C. orbiculatus, which has anti-tumor and anti-inflammatory biological effects. Our previous study showed that COE had a certain reversal effect on the precancerous lesions of gastric cancer (PLGC) in rats, but the exact mechanism of action remains elusive. We aimed to explore the therapeutic effects of COE on PLGC and the potential mechanisms. Methods: The PLGC rat model was successfully constructed by N-methyl-N´-nitro-N-nitrosoguanidine (MNNG) multifactorial induction method. Then, COE was prepared to treat the PLGC rat model. Hematoxylin & eosin staining was used to observe gastric mucosal lesions in rats, AB-PAS and HID-AB staining were used to observe intestinal metaplasia. PDCD4-ATG5 signaling pathway was detected by immunohistochemistry (IHC) and reverse transcription polymerase chain reaction (RT-PCR) in vivo, and autophagy level was detected by IHC, transmission electron microscopy, and RT-PCR in vivo. Besides, the PLGC (MC) cell model was successfully constructed by treating GES-1 cells with MNNG. Then, the morphology, proliferation, and apoptosis of MC cells, and the role of the PDCD4-ATG5 signaling pathway and autophagy in MC cells were evaluated by COE and after the overexpression of PDCD4 treatment. Key findings: COE significantly improved gastric mucosal injury and cellular heteromorphism and retarded the progression of PLGC in rats. Further studies indicated COE not only inhibited the level of autophagy but also interfered with the PDCD4-ATG5 signaling pathway in vivo. On the other hand, COE treatment could effectively reverse MC cell damage, inhibit MC cell proliferation, and promote MC cell apoptosis. Furthermore, COE also promoted PDCD4 and inhibited ATG5 expression in vitro, and the inhibitory effect of COE on ATG5-mediated autophagy was further enhanced after the overexpression of PDCD4. Conclusions: The study revealed that COE could regulate the PDCD4-ATG5 signaling pathway to inhibit autophagy in gastric epithelial cells, which contributes to reversing the progression of PLGC. [ABSTRACT FROM AUTHOR]

ABSTRACT Programmed cell death protein 4 (PDCD4) is instrumental in regulating a range of cellular processes such as translation, apoptosis, signal transduction, and inflammatory responses. There is a notable inverse correlation between PDCD4 and the mammalian target of rapamycin (mTOR) pathway, which is integral to cellular growth control. Activation of mTOR is associated with the degradation of PDCD4. Although the role of PDCD4 is well established in oncogenesis and immune response regulation, its function in mycobacterial infections and its interplay with the mTOR pathway necessitate further elucidation. This study investigates the modulation of PDCD4 expression in the context of mycobacterial infections, revealing a consistent pattern of downregulation across diverse mycobacterial species. This observation underscores the potential utility of PDCD4 as a biomarker for assessing mTOR pathway activation during such infections. Building on this finding, we employed a novel approach using PDCD4-based mTOR (Tor)-signal-indicator (TOSI) reporter cells for the high-throughput screening of FDA-approved drugs, focusing on mTOR inhibitors. This methodology facilitated the identification of several agents, inclusive of known mTOR inhibitors, which upregulated PDCD4 expression and concurrently exhibited efficacy in impeding mycobacterial proliferation within macrophages. These results not only reinforce the significance of PDCD4 as a pivotal marker in the understanding of infectious diseases, particularly mycobacterial infections, but also illuminate its potential in the identification of mTOR inhibitors, thereby contributing to the advancement of therapeutic strategies.IMPORTANCEThis study emphasizes the critical role of the mammalian target of rapamycin (mTOR) pathway in macrophage responses to mycobacterial infections, elucidating how mycobacteria activate mTOR, resulting in PDCD4 degradation. The utilization of the (Tor)-signal-indicator (TOSI) vector for real-time monitoring of mTOR activity represents a significant advancement in understanding mTOR regulation during mycobacterial infection. These findings deepen our comprehension of mycobacteria's innate immune mechanisms and introduce PDCD4 as a novel marker for mTOR activity in infectious diseases. Importantly, this research laid the groundwork for high-throughput screening of mTOR inhibitors using FDA-approved drugs, offering the potential for repurposing treatments against mycobacterial infections. The identification of drugs that inhibit mTOR activation opens new avenues for host-directed therapies, marking a significant step forward in combating tuberculosis and other mycobacterial diseases.

Chronic obstructive pulmonary disease (COPD) kills more than 3 million people worldwide every year. Despite progress in the treatment of symptoms and prevention of acute exacerbations, few advances have been made to ameliorate disease progression or affect mortality. Exercise plays a positive role in the prevention and treatment of diaphragm dysfunction in COPD, and the changes in diaphragm structure and function induced by exercise are closely related to the regulation of oxidative stress. But the mechanism remains unclear. So the aim of this study was to reveal the therapeutic mechanism of exercise to COPD using both in vivo and in vitro experiments. In this study, cigarette smoke (CS) induced COPD mice model, treadmill aerobic training for COPD mice were constructed and cigarette smoke extract (CSE) induced bronchial epithelial cells (BECs) model were used for COPD study. Bioinformatics analysis, luciferase reporting analysis, and RT-qPCR detection were used to clarify the interacted relationship among lncRNA, miRNA, and mRNA. ROS, inflammatory cytokines expression, and EMT relative protein α-SMA were detected using immunofluorescence and ELISA detection. The result shows that exercise ameliorates COPD induced lung injury by inhibit ROS, inflammation, and epithelial-mesenchymal transition (EMT) relative protein α-SMA expression. RT-qPCR detection shows that lnc-H19 expression was increased in lung tissues of COPD mice. Exercise decreased COPD induced lnc-H19 expression. Downregulation lnc-H19 inhibits COPD mediated lung injury. Bioinformatics analysis and luciferase reporting analysis confirmed that miR-181 and PDCD4 were downstream targets of lnc-H19. Upregulation of PDCD4 or downregulation of miR-181 reversed the protective effect of si-lnc-H19 to BECs after exposure to CSE. In conclusion, lncRNA H19 contributes to smoke-related chronic obstructive pulmonary disease by targeting miR-181/PDCD4 Axis.

Background: Hypoxic-ischemic brain damage (HIBD) is a prevalent brain injury with high mortality and morbidity. It results from hypoxia and ischemia of the brain due to various perinatal factors. A previous study showed that knockdown of programmed cell death factor 4 (PDCD4) could reduce infarction injury resulting from ischemia/reperfusion injury. However, exact mechanism by which PDCD4 acts in HIBD is not yet understood. Our aim in present investigation was to investigate the function and mechanism of PDCD4 in alleviating HIBD. Methods: An HIBD model was developed using neonatal rats. After 48 h of modeling, short-term neurological function was evaluated and the brain tissue removed for assessment of cerebral infarct volume and brain water content (BWC). A cell model of oxygen glucose deprivation/reoxygenation (OGD/R) was also constructed. Overexpression or knockdown of insulin-like growth factor 2 mRNA binding protein 3 (IGF2BP3) or PDCD4 was performed in pretreated cells. Results: The geotaxis reflex time, cerebral infarct volume, and BWC all increased after HIBD in this neonatal rat model. Additionally, the levels of PDCD4 and of the N6-Methyladenosine (m6A) reader protein IGF2BP3 were increased in HIBD rats and OGD/R-stimulated pheochromocytoma (PC12) cells relative to controls. Moreover, OGD/R-stimulated pheochromocytoma PC12 cells showed decreased cell viability, increased apoptosis, and elevated Interleukin 6 (IL-6), Interleukin 1 β (IL-1β), and tumor necrosis factor-α (TNF-α) contents. These features were reversed after knocking down IGF2BP3. The interaction between IGF2BP3 protein and PDCD4 mRNA was confirmed by RNA immunoprecipitation and RNA pull-down assays. Furthermore, knockdown of IGF2BP3 in OGD/R-stimulated PC12 cells reduced cell damage via down-regulation of PDCD4. Finally, the IGF2BP3/PDCD4 axis alleviated OGD/R-induced cell injury in primary cortical neurons (PCNs). Conclusions: PDCD4 and m6A reader protein IGF2BP3 were up-regulated in an HIBD neonatal rat model. Knockdown of IGF2BP3 in OGD/R-stimulated PC12 cells or PCNs alleviated cell damage through reducing PDCD4.

Introduction: Sepsis is a pathogenic syndrome of prolonged excessive inflammation and immunosuppression produced by invading pathogens. Programmed cell death 4 (PDCD4) may be implicated in a range of inflammatory lesions, and this study aimed to confirm the involvement of PDCD4 in septic lung injury. Materials and methods: Mice and bronchial epithelial 16HBE cells were separately subjected to CLP and LPS to generate in vivo and in vitro models. Following the level of PDCD4 was determined, the impacts of PDCD4 knockdown on mouse lung injury degree, inflammation, apoptosis, and pyroptosis levels were evaluated. Afterward, cells were treated with the NLRP3 agonist, and the influences of NLRP3 activation on the regulations of PDCD4 knockdown were determined. Results: PDCD4 was elevated following mice developed septic lung injury, PDCD4 knockdown ameliorated septic lung injury and reduced lung inflammation and apoptosis. Moreover, PDCD4 knockdown suppressed NLRP3-mediated pyroptosis, indicating that PDCD4 also mediated pyroptosis. According to cellular models, NLRP3 activation broke the effects of PDCD4 knockdown on cells. Conclusions: The current study reveals that PDCD4 governs NLRP3-mediated pyroptosis in septic lung injury. PDCD4 is not only related to apoptosis and expands the knowledge of PDCD4 regulation of different cell death modes. [ABSTRACT FROM AUTHOR]

Acute myeloid leukemia (AML) is a common heterogeneous malignancy. Novel molecular markers aid diagnosis, patient sub-categorization, and optimal clinical decisions. Here, we explored the prognostic implications associated with the expression of the programmed cell death (PDCD) family of molecules in AML patients. Based on the findings from the TCGA and OHSU cohorts, we observed that the mRNA abundance of PDCD4 is significantly higher compared to other molecules within the PDCD family. Furthermore, high expression of PDCD4 was associated with predicted long-term patient survival in diagnosed AML patients. In the chemotherapy group, patients with high PDCD4 expression showed a tendency toward longer overall survival (OS) (P = 0.0266) and event-free survival (EFS) (P = 0.0008). High PDCD4 levels served as a favorable independent predictor for both OS and EFS in AML patients. However, subgroup analyses in the hematopoietic stem cell transplantation (HSCT) group revealed no significant difference in OS or EFS between individuals with high and low PDCD4 expression. Furthermore, in the low PDCD4 expression group, AML patients who underwent HSCT experienced improved survival outcomes (P = 0.0015), helping to mitigate the unfavorable prognosis associated with PDCD4 downregulation. Conversely, in the high PDCD4 expression group, HSCT offered a notable short-term survival advantage, while patients with high PDCD4 expression responded favorably to long-term survival through chemotherapy. Biological function enrichment showed that the expression of PDCD4 was correlated with complement and coagulation cascades, cell receptor signaling pathways, and cholesterol metabolism. The findings from this study will aid in better categorizing heterogeneous AML patients and guiding more appropriate clinical decision-making. [ABSTRACT FROM AUTHOR]

Objective Exploring the influence of rapamycin on the progressing of hepatocellular carcinoma(HCC) in H-ras 12V transgenic mice. Methods The expression level of miRNA in liver tissue and peritumor tissue of transgenic mice was detected by high-throughput sequencing of miRNAs. Treatment of transgenic mice with rapamycin and the changes of tumor morphology were detected. The miR-183 expression levels were detected by RT-qPCR. The protein expression levels of mTOR, ERK and PDCD4, the downstream target gene of miR-183, were detected by Western blot. Results Compared with the peritumor tissue, the miR-183 expression in hepatocellular carcinoma tissue was increased significantly (P＜0.01). The protein expression levels of PDCD4 were decreased significantly(P＜0.05). Compared with the control group, after intervention with rapamycin, the counting of liver tumors decreased significantly(P＜0.05). The liver co-efficient decreased significantly(P＜0.05). The ERK phosphorylation increased significantly (P＜0.05). The miR-183 expression was decreased significantly (P＜0.05). The protein level of PDCD4 increased significantly (P＜0.05). Conclusions Rapamycin can alleviate hepatocellular carcinoma progression in H-ras 12V transgenic mice.

Objective Exploring the influence of rapamycin on the progressing of hepatocellular carcinoma (HCC) in H-ras 12V transgenic mice. Methods The expression level of miRNA in liver tissue and peritumor tissue of transgenic mice was detected by high-throughput sequencing of miRNAs. Treatment of transgenic mice with rapamycin and the changes of tumor morphology were detected. The miR-183 expression levels were detected by RT-qPCR. The protein expression levels of mTOR, ERK and PDCD4, the downstream target gene of miR-183, were detected by Western blot. Results Compared with the peritumor tissue, the miR-183 expression in hepatocellular carcinoma tissue was increased significantly (P＜0.01) . The protein expression levels of PDCD4 were decreased significantly (P＜0.05) . Compared with the control group, after intervention with rapamycin, the counting of liver tumors decreased significantly (P＜0.05) . The liver co-efficient decreased significantly (P＜0.05) . The ERK phosphorylation increased significantly (P＜0.05) . The miR-183 expression was decreased significantly (P＜0.05) . The protein level of PDCD4 increased significantly (P＜0.05) . Conclusions Rapamycin can alleviate hepatocellular carcinoma progression in H-ras 12V transgenic mice. [ABSTRACT FROM AUTHOR]

Medial arterial calcification (MAC), a systemic vascular disease different from atherosclerosis, is associated with an increased incidence of cardiovascular events. Several studies have demonstrated that ambient temperature is one of the most important factors affecting cardiovascular events. However, there has been limited research on the effect of different ambient temperatures on MAC. In the present study, we showed that cold temperature exposure (CT) in mice slowed down the formation of vitamin D (VD)-induced vascular calcification compared with room temperature exposure (RT). To investigate the mechanism involved, we isolated plasma-derived exosomes from mice subjected to CT or RT for 30 days (CT-Exo or RT-Exo, respectively). Compared with RT-Exo, CT-Exo remarkably alleviated the calcification/senescence formation of vascular smooth muscle cells (VSMCs) and promoted autophagy by activating the phosphorylation of AMP-activated protein kinase (p-AMPK) and inhibiting phosphorylation of mammalian target of rapamycin (p-mTOR). At the same time, CT-Exo promoted autophagy in β-glycerophosphate (β-GP)-induced VSMCs. The number of autophagosomes and the expression of autophagy-related proteins ATG5 and LC3B increased, while the expression of p62 decreased. Based on a microRNA chip microarray assay and real-time polymerase chain reaction, miR-320a-3p was highly enriched in CT-Exo as well as thoracic aortic vessels in CT mice. miR-320a-3p downregulation in CT-Exo using AntagomiR-320a-3p inhibited autophagy and blunted its anti-calcification protective effect on VSMCs. Moreover, we identified that programmed cell death 4 (PDCD4) is a target of miR-320a-3p, and silencing PDCD4 increased autophagy and decreased calcification in VSMCs. Treatment with CT-Exo alleviated the formation of MAC in VD-treated mice, while these effects were partially reversed by GW4869. Furthermore, the anti-arterial calcification protective effects of CT-Exo were largely abolished by AntagomiR-320a-3p in VD-induced mice. In summary, we have highlighted that prolonged cold may be a good way to reduce the incidence of MAC. Specifically, miR-320a-3p from CT-Exo could protect against the initiation and progression of MAC via the AMPK/mTOR autophagy pathway. [ABSTRACT FROM AUTHOR]

This study aimed to clarify whether circulating miR-21 represents a predictive biomarker in patients with head and neck squamous cell carcinoma (HNSCC) undergoing chemoradiotherapy, and to investigate the effect of miR-21 inhibitor for chemoradiation in human SCC cells. Plasma samples were obtained from 22 patients with HNSCC and 25 non-cancer volunteers. Plasma miR-21 expression was measured using real-time quantitative reverse transcription polymerase chain reaction. The effects of miR-21 inhibitor in human SCC cells were investigated by performing 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, flow cytometry and western blot analysis. As a result, plasma miR-21 expression was higher in HNSCC patients than in control patients (P  < 0.001). Seven patients with recurrence showed significantly higher plasma miR-21 than the 15 patients without recurrence. And high miR-21 expression group showed poor overall survival. Moreover, miR-21 inhibition significantly enhanced cisplatin- or radiation-induced apoptosis. Western blot analysis suggested the programmed cell death 4 protein as a potential target of miR-21 in relation to apoptosis. In conclusion, this study provides new insights into the role of miR-21 as a predictive biomarker for HNSCC treated with chemoradiotherapy and suggests a potential target to improve the effects of chemoradiotherapy against HNSCC. [ABSTRACT FROM AUTHOR]

Introduction: Medullary thyroid cancer (MTC) is a rare type of neuroendocrine tumor that produces a hormone called calcitonin (CT). Thyroidectomy is the preferred treatment for MTC, as chemotherapy has been shown to have limited effectiveness. Targeted therapy approaches are currently being used for patients with advanced, metastatic MTC. Several studies have identified microRNAs, including miR-21, as playing a role in the development of MTC. Programmed cell death 4 (PDCD4) is a tumor suppressor gene that is an important target of miR-21. Our previous research has shown that high levels of miR-21 are associated with low PDCD4 nuclear scores and high CT levels. The aim of this study was to investigate the potential of this pathway as a novel therapeutic target for MTC. Methods: We used a specific process to silence miR-21 in two human MTC cell lines. We studied the effect of this anti-miRNA process alone and in combination with cabozantinib and vandetanib, two drugs used in targeted therapy for MTC. We analyzed the effect of miR-21 silencing on cell viability, PDCD4 and CT expression, phosphorylation pathways, cell migration, cell cycle, and apoptosis. Results: Silencing miR-21 alone resulted in a reduction of cell viability and an increase in PDCD4 levels at both mRNA and protein levels. It also led to a reduction in CT expression at both mRNA and secretion levels. When combined with cabozantinib and vandetanib, miR-21 silencing did not affect cell cycle or migration but was able to enhance apoptosis. Conclusion: Silencing miR-21, although not showing synergistic activity with TKIs (tyrosine kinase inhibitors), represents a potential alternative worth exploring as a therapeutic target for MTC. [ABSTRACT FROM AUTHOR]

The programmed cell death protein 4 (PDCD4), a well-known tumor suppressor, inhibits translation initiation and cap-dependent translation by inhibiting the helicase activity of EIF4A. The EIF4A tends to target mRNAs with a structured 5′-UTR. In addition, PDCD4 can also prevent tumorigenesis by inhibiting tumor promoter-induced neoplastic transformation, and studies indicate that PDCD4 binding to certain mRNAs inhibits those mRNAs’ translation. A previous study demonstrated that PDCD4 inhibits the translation of p53 mRNA and that treatment with DNA-damaging agents down-regulates PDCD4 expression but activates p53 expression. The study further demonstrated that treatment with DNA-damaging agents resulted in the downregulation of PDCD4 expression and an increase in p53 expression, suggesting a potential mechanism by which p53 regulates the expression of PDCD4. However, whether p53 directly regulates PDCD4 remains unknown. Herein, we demonstrate for the first time that p53 regulates PDCD4 expression. Firstly, we found that overexpression of p53 in p53-null cells (H1299 and Saos2 cells) decreased the PDCD4 protein level. Secondly, p53 decreased PDCD4 promoter activity in gene reporter assays. Moreover, we demonstrated that mutations in p53 (R273H: contact hotspot mutation, and R175H: conformational hotspot mutation) abolished p53-mediated PDCD4 repression. Furthermore, mutations in the DNA-binding domain, but not in the C-terminal regulatory domain, of p53 disrupted p53-mediated PDCD4 repression. Finally, the C-terminal regulatory domain truncation study showed that the region between aa374 and aa370 is critical for p53-mediated PDCD4 repression. Taken together, our results suggest that p53 functions as a novel regulator of PDCD4, and the relationship between p53 and PDCD4 may be involved in tumor development and progression.

Introduction: Contusion spinal cord injury is involved in a number of cellular, biochemical and molecular changes. We studied the overall expression pattern of miRNAs on day 1 and 3 after spinal cord injury and the involved pathways. Material and methods: A spinal cord injury model was developed by contusion injury in rats. Microarray analysis and qRT-PCR were done for expression of miRs. The Basso, Beattie and Bresnahan (BBB) locomotor score was determined after spinal injury. Lesions at the injured site were analyzed by cresyl staining. Western blot analysis was carried out to analyze protein levels. Immunohistochemical staining was done to evaluate immunoreactivity. TUNEL assay was performed to determine the number of apoptotic cells. Results: The microarray analysis data suggested that about eight miRs were upregulated whereas four were downregulated in rats subjected to spinal cord injury on day 1. On comparing sham operated rats from the day 3 group two miRs were overexpressed and four were downregulated. miR-19a was the most deregulated. miR-19a antagomir was used as an inhibitor, which aggravated the functional deficit, decreased the protection of spinal cord tissue and elevated the number of apoptotic cells. The treatment of miR-19a antagomir increased the expression of FasL along with PTEN, but it failed to affect the levels of PDCD4. Conclusions: The results suggested that miR-19a plays a potential role in halting the neuronal cell death spinal cord injury and that the protective role of miR-19a may be due to its regulatory effect on pro-apoptotic genes. [ABSTRACT FROM AUTHOR]

BACKGROUND: circRNAs (circRNAs) are involved in the process of cerebral ischemia-reperfusion injury (CI/RI). Our study aims to explore circRBM33 in the endothelial function of the blood-brain barrier (BBB). METHODS: The mouse middle cerebral artery occlusion model (MCAO) was established and restored to perfusion, and OGD/R-induced endothelial cells were used to simulate CI/RI. circRBM33, miR-6838-5p and PDCD4, as well as Occludin, ZO-1 and Claudin-5 TJs were evaluated by quantitative PCR and Western blot. The ring structure of circRBM33 was verified by RNAse R and actinomycin D experiments. MTT and LDH Cytotoxicity assay determined viability and toxicity, and flow cytometry determined apoptosis rate. Inflammatory cytokines and the number of microglia in brain tissue were measured by ELISA and IHC. The interaction between genes was verified by RIP and dual luciferase reporter assay. RESULTS: circRBM33 was a circrRNA present in the cytoplasm and up-regulated in the brain tissue of MCAO mice and OGD/R-induced endothelial cells. Silenced circRBM33 promoted Occludin, ZO-1, and Claudin-5 expression and cell proliferation, and inhibited cytotoxicity, inflammatory response, and apoptosis. Functionally, circRBM33-absorbed miR-6838-5p was involved in regulating PDCD4, leading to endothelial cell dysfunction, and thus affecting the function of the BBB. CONCLUSIONS: circRBM33 by mediating miR-6838-5p/PDCD4 axis induces endothelial dysfunction, thereby affecting the BBB in mice with CI/RI. [ABSTRACT FROM AUTHOR]

Although programmed cell death 4 (PDCD4) was initially reported as a tumor suppressor and has been shown to inhibit cancer cell growth and metastasis, recent studies have demonstrated that loss of PDCD4 expression also induces growth inhibition by inducing apoptosis and/or cellular senescence. At present, the roles of PDCD4 in the activation and profibrogenic properties of myofibroblasts, which are critically involved in organ fibrosis, such as that in the liver, are unclear. We, therefore, investigated the roles of PDCD4 in myofibroblasts using human hepatic stellate cell line Lieming Xu-2 (LX-2). PDCD4 knockdown inhibited LX-2 proliferation and induced a senescent phenotype with increased β-galactosidase staining and p21 expression in a p53-independent manner together with downregulation of the notch signaling mediator RBJ-κ/CSL. During PDCD4 knockdown, alpha smooth muscle actin (α-SMA; an activation marker of myofibroblasts), matrix metalloproteinases MMP-1 and MMP-9, and collagen IV were upregulated, but the expression of collagen1α1 and collagen III was markedly downregulated without any marked change in the expression of tissue inhibitor of metalloproteinase-1 (TIMP-1). These results demonstrated that knockdown of PDCD4 induced the cellular senescence phenotype and activated myofibroblasts while suppressing the profibrogenic phenotype, suggesting roles of PDCD4 in cellular senescence and fibrogenesis in the liver. [ABSTRACT FROM AUTHOR]

IntroductionMedullary thyroid cancer (MTC) is a rare type of neuroendocrine tumor that produces a hormone called calcitonin (CT). Thyroidectomy is the preferred treatment for MTC, as chemotherapy has been shown to have limited effectiveness. Targeted therapy approaches are currently being used for patients with advanced, metastatic MTC. Several studies have identified microRNAs, including miR-21, as playing a role in the development of MTC. Programmed cell death 4 (PDCD4) is a tumor suppressor gene that is an important target of miR-21. Our previous research has shown that high levels of miR-21 are associated with low PDCD4 nuclear scores and high CT levels. The aim of this study was to investigate the potential of this pathway as a novel therapeutic target for MTC.MethodsWe used a specific process to silence miR-21 in two human MTC cell lines. We studied the effect of this anti-miRNA process alone and in combination with cabozantinib and vandetanib, two drugs used in targeted therapy for MTC. We analyzed the effect of miR-21 silencing on cell viability, PDCD4 and CT expression, phosphorylation pathways, cell migration, cell cycle, and apoptosis.ResultsSilencing miR-21 alone resulted in a reduction of cell viability and an increase in PDCD4 levels at both mRNA and protein levels. It also led to a reduction in CT expression at both mRNA and secretion levels. When combined with cabozantinib and vandetanib, miR-21 silencing did not affect cell cycle or migration but was able to enhance apoptosis.ConclusionSilencing miR-21, although not showing synergistic activity with TKIs (tyrosine kinase inhibitors), represents a potential alternative worth exploring as a therapeutic target for MTC.

WWP2 is a HECT-type E3 ubiquitin ligase that regulates various physiological and pathological activities by binding to different substrates, but its role in atherosclerosis (AS) remains largely unknown. The objective of the present study is to investigate the role and underlying molecular mechanisms of WWP2 in endothelial injury. We found that WWP2 expression is significantly decreased in Apolipoprotein E (ApoE)–/– mice. Overexpression of WWP2 attenuates oxidative stress and inflammation in AS mice, while knockdown of WWP2 has opposite effects. WWP2 overexpression alleviates oxidized low-density lipoprotein (ox-LDL)-induced human umbilical vein endothelial cell (HUVEC) injury, evidenced by the decreased oxidative stress levels and the secretion of inflammatory cytokines. Programmed cell death 4 (PDCD4) is identified as a potential substrate of WWP2. Co-immunoprecipitation (Co-IP) further demonstrates that WWP2 interacts with PDCD4, which is enhanced by ox-LDL treatment. Furthermore, the level of PDCD4 ubiquitination is significantly increased by WWP2 overexpression under the condition of MG132 treatment, while WWP2 knockdown shows opposite results. Subsequently, rescue experiments demonstrate that WWP2 knockdown further aggravates oxidative stress and inflammation in ox-LDL-treated HUVECs, while knockdown of PDCD4 alleviates this effect. Moreover, the use of sn-protoporphyrin (SnPP), an inhibitor of HO-1 pathway, confirms that PDCD4 enhances endothelial injury induced by ox-LDL through inhibiting HO-1 pathway. In conclusion, our results suggest that WWP2 protects against atherosclerosis progression via the PDCD4/HO-1 pathway, which may provide a novel treatment strategy for atherosclerosis.

The programmed cell death protein 4 (PDCD4), a well-known tumor suppressor, inhibits translation initiation and cap-dependent translation by inhibiting the helicase activity of EIF4A. The EIF4A tends to target mRNAs with a structured 5′-UTR. In addition, PDCD4 can also prevent tumorigenesis by inhibiting tumor promoter-induced neoplastic transformation, and studies indicate that PDCD4 binding to certain mRNAs inhibits those mRNAs' translation. A previous study demonstrated that PDCD4 inhibits the translation of p53 mRNA and that treatment with DNA-damaging agents down-regulates PDCD4 expression but activates p53 expression. The study further demonstrated that treatment with DNA-damaging agents resulted in the downregulation of PDCD4 expression and an increase in p53 expression, suggesting a potential mechanism by which p53 regulates the expression of PDCD4. However, whether p53 directly regulates PDCD4 remains unknown. Herein, we demonstrate for the first time that p53 regulates PDCD4 expression. Firstly, we found that overexpression of p53 in p53-null cells (H1299 and Saos2 cells) decreased the PDCD4 protein level. Secondly, p53 decreased PDCD4 promoter activity in gene reporter assays. Moreover, we demonstrated that mutations in p53 (R273H: contact hotspot mutation, and R175H: conformational hotspot mutation) abolished p53-mediated PDCD4 repression. Furthermore, mutations in the DNA-binding domain, but not in the C-terminal regulatory domain, of p53 disrupted p53-mediated PDCD4 repression. Finally, the C-terminal regulatory domain truncation study showed that the region between aa374 and aa370 is critical for p53-mediated PDCD4 repression. Taken together, our results suggest that p53 functions as a novel regulator of PDCD4, and the relationship between p53 and PDCD4 may be involved in tumor development and progression. [ABSTRACT FROM AUTHOR]

The apoptosis of grafted islets is an urgent problem due to the high rate of islet loss soon after transplantation. MicroRNA-21-5p (miR-21-5p) is an essential mediator of bone marrow mesenchymal stem cells-derived exosomes (BMSCs-Exo) during anti-apoptosis, but its effect and the underlying molecular mechanism in islet transplantation remain partially understood. Here, we found that miR-21-5p could be delivered to islet cells via BMSCs-Exo. Subsequently, we demonstrated that miR-21-5p overexpression reduced apoptosis in islets and INS-1 cells, whereas miR-21-5p inhibition enhanced apoptosis. A mechanistic analysis involving RNA sequencing and bioinformatic analysis was performed to determine the interaction between miR-21-5p and its target gene programmed cell death 4 (PDCD4), which was further verified by a dual luciferase assay. In vivo, the grafted islets overexpressing miR-21-5p showed a higher survival rate, better insulin secretion function, and a lower apoptosis rate. In conclusion, these results demonstrated that miR‑21‑5p from BMSCs-Exo protects against the apoptosis of grafted islets by inhibiting PDCD4 expression. Hence, miR-21-5p can be used as a cell-free therapeutic agent to minimize β-cell apoptosis at the early stage of islet transplantation. We demonstrated that BMSCs could deliver exosomes containing miR-21-5p into islet cells.Then, we found that miR-21-5p overexpression attenuated apoptosis of islets and rat insulinoma (INS-1) cells, while miR-21-5p inhibition significantly promoted apoptosis.The upregulated miR-21-5p directly binds to the 3'UTR of PDCD4, thereby reducing apoptosis in transplanted islets. This study confirms the results of previous studies, suggesting that miR-21-5p can be used as a therapeutic agent to minimize β-cell apoptosis in the early stage of islet transplantation and thus improve the transplantation outcome. [ABSTRACT FROM AUTHOR]

Cells employ several adaptive mechanisms under conditions of accelerated cell division, such as the unfolded protein response (UPR). The UPR is composed of a tripartite signaling system that involves ATF6, PERK, and IRE1, which maintain protein homeostasis (proteostasis). However, deregulation of protein translation initiation could be associated with breast cancer (BC) chemoresistance. Specifically, eukaryotic initiation factor-4A (eIF4A) is involved in the unfolding of the secondary structures of several mRNAs at the 5′ untranslated region (5′-UTR), as well as in the regulation of targets involved in chemoresistance. Importantly, the tumor suppressor gene PDCD4 could modulate this process. This regulation might be disrupted in chemoresistant triple negative-BC (TNBC) cells. Therefore, we characterized the effect of doxorubicin (Dox), a commonly used anthracycline medication, on human breast carcinoma MDA-MB-231 cells. Here, we generated and characterized models of Dox chemoresistance, and chemoresistant cells exhibited lower Dox internalization levels followed by alteration of the IRE1 and PERK arms of the UPR and triggering of the antioxidant Nrf2 axis. Critically, chemoresistant cells exhibited PDCD4 downregulation, which coincided with a reduction in eIF4A interaction, suggesting a sophisticated regulation of protein translation. Likewise, Dox-induced chemoresistance was associated with alterations in cellular migration and invasion, which are key cancer hallmarks, coupled with changes in focal adhesion kinase (FAK) activation and secretion of matrix metalloproteinase-9 (MMP-9). Moreover, eIF4A knockdown via siRNA and its overexpression in chemoresistant cells suggested that eIF4A regulates FAK. Pro-atherogenic low-density lipoproteins (LDL) promoted cellular invasion in parental and chemoresistant cells in an MMP-9-dependent manner. Moreover, Dox only inhibited parental cell invasion. Significantly, chemoresistance was modulated by cryptotanshinone (Cry), a natural terpene purified from the roots of Salvia brandegeei. Cry and Dox co-exposure induced chemosensitization, connected with the Cry effect on eIF4A interaction. We further demonstrated the Cry binding capability on eIF4A and in silico assays suggest Cry inhibition on the RNA-processing domain. Therefore, strategic disruption of protein translation initiation is a druggable pathway by natural compounds during chemoresistance in TNBC. However, plasmatic LDL levels should be closely monitored throughout treatment. [ABSTRACT FROM AUTHOR]

We aimed to explore the underlying mechanism behind the cisplatin (DDP) resistance of non-small cell lung cancer (NSCLC) cells to identify novel potential therapeutic targets to overcome chemoresistance. Real-time quantitative polymerase chain reaction (RT-qPCR) and Western blot assay were applied to analyze RNA and protein expression, respectively. Cell Counting Kit-8 (CCK8) assay was conducted to analyze the DDP resistance of NSCLC cells. Colony formation assay and 5-Ethynyl-2′-deoxyuridine (EdU) assay were performed to analyze cell proliferation ability. Flow cytometry was applied to assess cell apoptosis. Cell migration and invasion were assessed by transwell assays. Cell glycolytic metabolism was analyzed using commercial kits. Dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay were performed to test the intermolecular target relations. Circular RNA_0030998 (circ_0030998) was down-regulated in DDP-resistant NSCLC tissues and cell lines. Circ_0030998 overexpression restrained the DDP resistance, proliferation, migration, invasion and glycolytic metabolism and triggered the apoptosis of NSCLC cells. Circ_0030998 overexpression contributed to the anti-tumor effect of DDP in the growth of xenograft tumor in vivo. MicroRNA-1323 (miR-1323) was a molecular target of circ_0030998 in NSCLC cells. Circ_0030998 overexpression-mediated effects on the DDP resistance and malignant properties of NSCLC cells were largely based on its negative regulation of miR-1323. MiR-1323 interacted with programmed cell death 4 (PDCD4). Circ_0030998 positively regulated PDCD4 expression partly through sponging miR-1323. MiR-1323 silencing restrained DDP resistance and progression of NSCLC partly through up-regulating PDCD4. Circ_0030998 suppressed DDP resistance and NSCLC progression depending on the regulation of miR-1323/PDCD4 axis. [ABSTRACT FROM AUTHOR]

The Tibetan pig is an endemic economic animal in the plateau region of China, and has a unique adaptation mechanism to the plateau hypoxic environment. Research into microRNAs (miRNAs) involved in the mechanism underlying hypoxia adaptation of Tibetan pig is very limited. Therefore, we isolated alveolar type II epithelial (ATII) cells from the lungs of the Tibetan pig, cultured them in normoxia/hypoxia (21% O2; 2% O2) for 48 h, and performed high-throughput sequencing analysis. We identified a hypoxic stress-related ssc-miR-141 and predicted its target genes. The target genes of ssc-miR-141 were mainly enriched in mitogen-activated protein kinase (MAPK), autophagy-animal, and Ras signaling pathways. Further, we confirmed that PDCD4 may serve as the target gene of ssc-miR-141. Real-time quantitative polymerase chain reaction (RT-qPCR) analysis was performed to confirm the expression levels of ssc-miR-141 and PDCD4, and a dual-luciferase gene reporter system was used to verify the targeted linkage of ssc-miR-141 to PDCD4. The results showed that the expression level of ssc-miR-141 in the hypoxia group was higher than that in the normoxia group, while the expression level of PDCD4 tended to show the opposite trend and significantly decreased under hypoxia. These findings suggest that ssc-miR-141 is associated with hypoxia adaptation and provide a new insight into the role of miRNAs from ATII cells of Tibetan pig in hypoxia adaptation. [ABSTRACT FROM AUTHOR]

This article aimed to investigate the role of miR‐208 in the apoptosis of myocardial tissues in acute myocardial infarction (AMI) mice. The AMI mouse model was constructed. Then, miR‐208 expression in AMI mice was regulated by transfection. The mouse myocardial tissues were subject to hematoxylin–eosin (HE) staining, TUNEL assay, and immunofluorescence analysis. H9c2 cell transfection and hypoxia induction were then completed, and cell apoptosis and cytokine levels were tested. Additionally, RNA pull‐down and dual luciferase reporter gene assays were conducted for exploring the relation of miR‐208 with programmed cell death 4 (PDCD4). Additionally, fluorescence in situ hybridization (FISH) was conducted for investigating miR‐208 and PDCD4 colocalization within H9c2 cells. AMI mice had severe damage, apoptosis, decreased miR‐208 expression, increased IL‐1β, IL‐6, IL‐8 levels, whereas reduced IL‐10 level within myocardial tissues. H9c2 cells under hypoxia induction exhibited decreased miR‐208 expression, promoted apoptosis, increased protein expression of Bax and cleaved‐caspase‐3, decreased protein expression of Bcl‐2 and caspase‐3, elevated IL‐1β, IL‐6, IL‐8 levels and decreased IL‐10 level. miR‐208 upregulation alleviated the damage and apoptosis of myocardial tissues in AMI mice. AMI mice with miR‐208 upregulation showed decreased expression of Bax and cleaved‐caspase‐3, increased expression of Bcl‐2 and caspase‐3, reduced levels of IL‐1β, IL‐6, IL‐8, whereas an increased level of IL‐10. miR‐208 showed direct inhibition of PDCD4. PDCD4 and miR‐208 were mainly co‐expressed in the cytoplasm. The upregulated PDCD4 expression abolished miR‐208's suppression of H9c2 cell apoptosis induced by hypoxia. Besides this, miR‐208 inhibited myocardial tissue apoptosis in AMI mice by inhibiting PDCD4 expression. [ABSTRACT FROM AUTHOR]

MiR-499a-5p was significantly downregulated in degenerative tissues and correlated with apoptosis. Nonetheless, the biological function of miR-499a-5p in acute ischemic stroke has been still unclear. In this study, we found that the plasma levels of miR-499a-5p were significantly downregulated in 64 ischemic stroke patients and negatively correlated with the National Institutes of Health Stroke Scale score. Then, we constructed cerebral ischemia/reperfusion (I/R) injury in rats after middle cerebral artery occlusion and subsequent reperfusion and oxygen–glucose deprivation and reoxygenation (OGD/R)-treated SH-SY5Y cell model. Transfection with miR-499a-5p mimic was accomplished by intracerebroventricular injection in the in vivo I/R injury model. We further found that miR-499a-5p overexpression decreased infarct volumes and cell apoptosis in the in vivo I/R stroke model using TTC and TUNEL staining. PDCD4 was a direct target of miR-499a-5p by luciferase report assay and Western blotting. Knockdown of PDCD4 reduced the infarct damage and cortical neuron apoptosis caused by I/R injury. MiR-499a-5p exerted neuroprotective roles mainly through inhibiting PDCD4-mediated apoptosis by CCK-8 assay, LDH release assay, and flow cytometry analysis. These findings suggest that miR-499a-5p might represent a novel target that regulates brain injury by inhibiting PDCD4-mediating apoptosis. [ABSTRACT FROM AUTHOR]

Nonalcoholic steatohepatitis (NASH) is a primary cause of liver cirrhosis and hepatocellular carcinoma, presenting a significant and unmet medical challenge. The necessity to investigate the molecular mechanisms underlying NASH is highlighted by the observed decrease in programmed cell death 4 (PDCD4) expression in NASH patients, suggesting that PDCD4 may play a protective role in maintaining liver health. In this study, we identify PDCD4 as a natural inhibitor of NASH development in mice. The absence of PDCD4 leads to the spontaneous progression of NASH. Notably, PDCD4-deficient hepatocytes display elevated major histocompatibility complex class II (MHCII) expression due to CIITA activation, indicating that PCDC4 prevents the abnormal transformation of hepatocytes into antigen-presenting cells (APCs). Cell co-culture experiments reveal that hepatocytes lacking PDCD4, which resemble APCs, can directly activate CD4 + T cells by presenting multiple peptides, resulting in the release of inflammatory factors. Additionally, both cellular and animal studies show that CIITA promotes lipid accumulation in hepatocytes and exacerbates NASH progression. In summary, our findings reveal a novel role of PDCD4 in regulating CIITA and MHCII expression during NASH development, offering new therapeutic approaches for NASH treatment., Competing Interests: Declaration of competing interest The authors declare no conflict of interest., (Copyright © 2024. Published by Elsevier Inc.)

Background: Hypoxic-ischemic brain damage (HIBD) is a prevalent brain injury with high mortality and morbidity. It results from hypoxia and ischemia of the brain due to various perinatal factors. A previous study showed that knockdown of programmed cell death factor 4 (PDCD4) could reduce infarction injury resulting from ischemia/reperfusion injury. However, exact mechanism by which PDCD4 acts in HIBD is not yet understood. Our aim in present investigation was to investigate the function and mechanism of PDCD4 in alleviating HIBD., Methods: An HIBD model was developed using neonatal rats. After 48 h of modeling, short-term neurological function was evaluated and the brain tissue removed for assessment of cerebral infarct volume and brain water content (BWC). A cell model of oxygen glucose deprivation/reoxygenation (OGD/R) was also constructed. Overexpression or knockdown of insulin-like growth factor 2 mRNA binding protein 3 (IGF2BP3) or PDCD4 was performed in pretreated cells., Results: The geotaxis reflex time, cerebral infarct volume, and BWC all increased after HIBD in this neonatal rat model. Additionally, the levels of PDCD4 and of the N6-Methyladenosine (m6A) reader protein IGF2BP3 were increased in HIBD rats and OGD/R-stimulated pheochromocytoma (PC12) cells relative to controls. Moreover, OGD/R-stimulated pheochromocytoma PC12 cells showed decreased cell viability, increased apoptosis, and elevated Interleukin 6 (IL-6), Interleukin 1 β (IL-1β), and tumor necrosis factor-α (TNF-α) contents. These features were reversed after knocking down IGF2BP3. The interaction between IGF2BP3 protein and PDCD4 mRNA was confirmed by RNA immunoprecipitation and RNA pull-down assays. Furthermore, knockdown of IGF2BP3 in OGD/R-stimulated PC12 cells reduced cell damage via down-regulation of PDCD4. Finally, the IGF2BP3/PDCD4 axis alleviated OGD/R-induced cell injury in primary cortical neurons (PCNs)., Conclusions: PDCD4 and m6A reader protein IGF2BP3 were up-regulated in an HIBD neonatal rat model. Knockdown of IGF2BP3 in OGD/R-stimulated PC12 cells or PCNs alleviated cell damage through reducing PDCD4., (© 2024 The Author(s). Published by IMR Press.)

Programmed cell death protein 4 (PDCD4) exerts critical functions as tumor suppressor and in immune cells to regulate inflammatory pro-cesses. The phosphoinositide 3-kinase (PI3K) promotes degradation of PDCD4 via mammalian target of rapamycin complex 1 (mTORC1). How-ever, additional pathways that may regulate PDCD4 expression are largely ill-defined. In this study, we have found that activation of the mitogen-activated protein kinase p38 promoted degradation of PDCD4 in macrophages and fibroblasts. Mechanistically, we identified a path-way from p38 and its substrate MAP kinase-activated protein kinase 2 (MK2) to the tuberous sclerosis complex (TSC) to regulate mTORC1-dependent degradation of PDCD4. Moreover, we provide evidence that TSC1 and TSC2 regulate PDCD4 expression via an additional mechanism independent of mTORC1. These novel data extend our knowledge of how PDCD4 expression is regulated by stress- and nutrient-sensing pathways.

microRNAs (miRNAs) are susceptible to environmental factors that might affect cellular function and impose negative effects on female reproduction. miR-21 is the most abundant miRNA in bovine granulosa cells and is widely reported as affected by Bisphenol A (BPA) exposure, yet the cause and consequences are not entirely elucidated. BPA is a synthetic endocrine disruptor associated with poor fertility. miR-21 function in bovine granulosa cells is investigated utilizing locked nucleic acid (LNA) oligonucleotides to suppress miR-21. Before measuring apoptosis and quantifying miR-21 apoptotic targets PDCD4 and PTEN, transfection was optimized and validated. BPA was introduced to see how it affects miR-21 regulation and which BPA-mediated effects are influenced by miR-21. miR-21 knockdown and specificity against additional miRNAs were confirmed. miR-21 was found to have antiapoptotic effects, which could be explained by its effect on the proapoptotic target PDCD4, but not PTEN. Previous findings of miR-21 overexpression were validated using BPA treatments, and the temporal influence of BPA on miR-21 levels was addressed. Finally, BPA effects on upstream regulators, such as VMP1 and STAT3, explain the BPA-dependent upregulation of miR-21 expression. Overall, this research enhances our understanding of miR-21 function in granulosa cells and the mechanisms of BPA-induced reproductive impairment. [ABSTRACT FROM AUTHOR]

Objectives Circular RNA (CircRNA) is a class of non-coding RNA transcripts, with multiple pathophysiological functions. Instead, the mechanism and function of circRNA in gastric cancer (GC) are not fully deciphered. Methods CircRNA_0026344 (circ_0026344), microRNA (miR)-590-5p and programmed cell death 4 (PDCD4) mRNA expression levels in GC tissues and cells were probed by quantitative real-time PCR. Cell viability, migration and aggressiveness were examined by cell counting kit-8 and transwell assays. Additionally, the interplay among circ_0026344 , miR-590-5p and PDCD4 was verified with bioinformatics and dual-luciferase reporter gene assay. Western blot was conducted to probe PDCD4 protein expression. Key findings Circ_0026344 expression was underexpressed in GC tissues and cells, which was associated with clinicopathological characteristics such as tumour size, tumor-node-metastasis stage and lymph node metastasis. Circ_0026344 overexpression restrained the malignant biological behaviours of GC cells, while circ_0026344 knockdown functioned oppositely. Circ_0026344 could act as a competing endogenous RNA of miR-590-5p to negatively modulate its expression, and this miRNA could mitigate the impact of circ_0026344 on GC cells. In addition, PDCD4 was identified as the downstream target of miR-590-5p , and PDCD4 expression was positively modulated by circ_0026344. Conclusions Circ_0026344 up-regulates PDCD4 expression via sponging miR-590-5p , thus inhibiting the progression of GC. This study further expounds the underlying molecular mechanism in the GC progression. [ABSTRACT FROM AUTHOR]

Data from GLOBOCAN 2020 estimates that there were 19.3 million new cases of cancer and 10.0 million cancer-related deaths in 2020 and that this is predicted to increase by 47% in 2040. The combined burden of cancers of the gastrointestinal (GI) tract, including oesophageal-, gastric- and colorectal cancers, resulted in 22.6% of the cancer-related deaths in 2020 and 18.7% of new diagnosed cases. Understanding the aetiology of GI tract cancers should have a major impact on future therapies and lessen this substantial burden of disease. Many cancers of the GI tract have suppression of the tumour suppressor Programmed Cell Death 4 (PDCD4) and this has been linked to the expression of microRNAs which bind to the untranslated region of PDCD4 mRNA and either inhibit translation or target the mRNA for degradation. This review highlights the properties of PDCD4 and documents the evidence for the regulation of PDCD4 expression by microRNAs in cancers of the GI tract. [ABSTRACT FROM AUTHOR]

The human programmed cell death 4 (PDCD4) gene was mapped at chromosome 10q24 and encodes the PDCD4 protein comprised of 469 amino acids. PDCD4 inhibits protein translation PDCD4 inhibits protein translation to suppress tumor progression, and its expression is frequently decreased in breast cancer. PDCD4 blocks translation initiation complex by binding eIF4A via MA-3 domains or by directly binding 5' mRNA internal ribosome entry sites with an RNA binding domain to suppress breast cancer progression and proliferation. Numerous regulators and biological processes including non-coding RNAs, proteasomes, estrogen, natural compounds and inflammation control PDCD4 expression in breast cancer. Loss of PDCD4 expression is also responsible for drug resistance in breast cancer. HER2 activation downregulates PDCD4 expression by activating MAPK, AKT, and miR-21 in aromatase inhibitor-resistant breast cancer cells. Moreover, modulating the microRNA/PDCD4 axis maybe an effective strategy for overcoming chemoresistance in breast cancer. Down-regulation of PDCD4 is significantly associated with short overall survival of patients, which suggests that PDCD4 may be an independent prognostic marker for breast cancer. [ABSTRACT FROM AUTHOR]

MiR-429 was reported to be downregulated in contrast-induced acute kidney injury (CI-AKI). However, whether miR-429 is functionally relevant with CI-AKI needs further investigation. Human renal tubular epithelial cell (HK-2) cells were stimulated with contrast media iodixanol to establish in vitro CI-AKI model. Cell Counting Kit-8 (CCK-8) was applied to access cell viability. Flow cytometry was performed to determine apoptosis. Quantitative real-time polymerase chain reaction (qRT-PCR) was applied to evaluate level of programmed cell death 4 (PDCD4) mRNA and miR-429 while western blot was applied to evaluate level of proteins including PDCD4, B-cell leukaemia/lymphoma 2 (Bcl-2), BCL2-associated X protein (Bax), cleaved caspase 3, cleaved caspase 9, p65, phosphorylated p65. Dual luciferase assay was used to validate miR-429 targeting PDCD4. MiR-429 was downregulated whereas PDCD4 was upregulated in contrast media iodixanol-stimulated HK-2 cells. MiR-429 overexpression elevated cell viability and attenuated cell apoptosis. Moreover, the activation of nuclear factor kappa-B (NF-κB) signalling was suppressed after miR-429 overexpression, while PDCD4 overexpression reversed these effects. MiR-429 directly targeted PDCD4 and negatively regulated its expression. CI-AKI induced NF-κB signalling activation and PDCD4 overexpression further promoted NF-κB signalling activation. However, the treatment of BAY11-7082 reversed above results. Overexpression of miR-429 attenuated apoptosis and elevated cell viability in a CI-AKI cell model via targeting PDCD4 and thus restraining NF-κB signalling.

The human programmed cell death 4 (PDCD4) gene was mapped at chromosome 10q24 and encodes the PDCD4 protein comprised of 469 amino acids. PDCD4 inhibits protein translation PDCD4 inhibits protein translation to suppress tumor progression, and its expression is frequently decreased in breast cancer. PDCD4 blocks translation initiation complex by binding eIF4A via MA-3 domains or by directly binding 5’ mRNA internal ribosome entry sites with an RNA binding domain to suppress breast cancer progression and proliferation. Numerous regulators and biological processes including non-coding RNAs, proteasomes, estrogen, natural compounds and inflammation control PDCD4 expression in breast cancer. Loss of PDCD4 expression is also responsible for drug resistance in breast cancer. HER2 activation downregulates PDCD4 expression by activating MAPK, AKT, and miR-21 in aromatase inhibitor-resistant breast cancer cells. Moreover, modulating the microRNA/PDCD4 axis maybe an effective strategy for overcoming chemoresistance in breast cancer. Down-regulation of PDCD4 is significantly associated with short overall survival of patients, which suggests that PDCD4 may be an independent prognostic marker for breast cancer.

Data from GLOBOCAN 2020 estimates that there were 19.3 million new cases of cancer and 10.0 million cancer-related deaths in 2020 and that this is predicted to increase by 47% in 2040. The combined burden of cancers of the gastrointestinal (GI) tract, including oesophageal-, gastric- and colorectal cancers, resulted in 22.6% of the cancer-related deaths in 2020 and 18.7% of new diagnosed cases. Understanding the aetiology of GI tract cancers should have a major impact on future therapies and lessen this substantial burden of disease. Many cancers of the GI tract have suppression of the tumour suppressor Programmed Cell Death 4 (PDCD4) and this has been linked to the expression of microRNAs which bind to the untranslated region of PDCD4 mRNA and either inhibit translation or target the mRNA for degradation. This review highlights the properties of PDCD4 and documents the evidence for the regulation of PDCD4 expression by microRNAs in cancers of the GI tract.

Abstract Background Circular RNAs (circRNAs) feature prominently in tumor progression. However, the biological function and molecular mechanism of circ_0003266 in colorectal cancer (CRC) require further investigation. Methods Circ_0003266 expression in 46 pairs CRC tissues / adjacent tissues, and CRC cell lines was detected by quantitative real-time polymerase chain reaction (qRT-PCR); after circ_0003266 was overexpressed or knocked down in CRC cells, cell proliferation, apoptosis, migration, and invasion were evaluated by the cell counting kit-8 (CCK-8), flow cytometry, and Transwell assays, respectively; the interaction among circ_0003266, miR-503-5p, and programmed cell death 4 (PDCD4) was confirmed using bioinformatics analysis and dual-luciferase reporter assay; PDCD4 protein expression in CRC cells was quantified using Western blot. Results Circ_0003266 was significantly lowly expressed in CRC tissues and cell lines. Circ_0003266 overexpression markedly repressed CRC cell proliferation, migration, and invasion, and accelerated the cell apoptosis, but its overexpression promoted the malignant phenotypes of CRC cells. PDCD4 was a direct target of miR-503-5p and circ_0003266 promoted PDCD4 expression by competitively sponging miR-503-5p. Conclusion Circ_0003266 suppresses the CRC progression via sponging miR-503-5p and regulating PDCD4 expressions, which suggests that circ_0003266 may serve as a novel target for the treatment of CRC.

Decidualization of endometrial stromal cells (ESCs) accompanied with embryo implantation is a key process in mammalian reproduction. Evidence suggests that maintenance of decidual cells function is essential. As a critical part in post-transcriptional gene regulation, microRNAs (miRNAs/miR) have been confirmed to be involved in decidualization. However, whether microRNAs regulate decidual cells function has not been reported. Aiming to clarify the role and potential mechanism of miRNAs in decidual cells, artificial induced decidualization model in mice was established. There are 94 differentially expressed miRNAs (≥two-fold change) between decidualized and non-decidualized tissues, including 60 upregulated and 34 downregulated miRNAs. Of the differentially expressed miRNAs, mmu-miR-21a is up-regulated. RT-qPCR also confirmed the up-regulation of mmu-miR-21a following decidualization in vivo and in vitro, and bioinformatic analysis and luciferase activity assay revealed Pdcd4 to be the target gene of mmu-miR-21a. Inhibition of mmu-miR-21a restrained secretory function of decidual cells induced by mESCs, accompanied with increase of Pdcd4 expression and resulted in the increase of cell apoptosis. In addition, we also determined the expression of hsa-miR-21 and Pdcd4 in human proliferative endometrial tissues and decidua tissues. hsa-miR-21 showed higher expression in human decidua tissues compared with proliferative endometrial tissues, while expression of Pdcd4 was contrary to that of hsa-miR-21. Similarly, cell apoptosis increased significantly in human endometrial stromal cell line in response to inhibition of hsa-miR-21. Collectively, we conclude that mmu-miR-21a/hsa-miR-21 may play a key role in regulating the function of decidual cells by inhibiting cell apoptosis through targeting Pdcd4.

STAT1 (Signal Transducer and Activator of Transcription 1), belongs to the STAT protein family, essential for cytokine signaling. It has been reported to have either context dependent oncogenic or tumor suppressor roles in different tumors. Earlier, we demonstrated that Glioblastoma multiforme (GBMs) overexpressing FAT1, an atypical cadherin, had poorer outcomes. Overexpressed FAT1 promotes pro-tumorigenic inflammation, migration/invasion by downregulating tumor suppressor gene, PDCD4. Here, we demonstrate that STAT1 is a novel mediator downstream to FAT1, in downregulating PDCD4 in GBMs. In-silico analysis of GBM databases as well as q-PCR analysis in resected GBM tumors showed positive correlation between STAT1 and FAT1 mRNA levels. Kaplan-Meier analysis showed poorer survival of GBM patients having high FAT1 and STAT1 expression. SiRNA-mediated knockdown of FAT1 decreased STAT1 and increased PDCD4 expression in glioblastoma cells (LN229 and U87MG). Knockdown of STAT1 alone resulted in increased PDCD4 expression. In silico analysis of the PDCD4 promoter revealed four putative STAT1 binding sites (Site1-Site4). ChIP assay confirmed the binding of STAT1 to site1. ChIP-PCR revealed decrease in the binding of STAT1 on the PDCD4 promoter after FAT1 knockdown. Site directed mutagenesis of Site1 resulted in increased PDCD4 luciferase activity, substantiating STAT1 mediated PDCD4 inhibition. EMSA confirmed STAT1 binding to the Site 1 sequence. STAT1 knockdown led to decreased expression of pro-inflammatory cytokines and EMT markers, and reduced migration/invasion of GBM cells. This study therefore identifies STAT1 as a novel downstream mediator of FAT1, promoting pro-tumorigenic activity in GBM, by suppressing PDCD4 expression. [ABSTRACT FROM AUTHOR]

Early life stress (ELS) increases the risk of depression later in life. Programmed cell death factor 4 (PDCD4), an apoptosis-related molecule, extensively participates in tumorigenesis and inflammatory diseases. However, its involvement in a person's susceptibility to ELS-related depression is unknown. To examine the effects and underlying mechanisms of PDCD4 on ELS vulnerability, we used a "two-hit" stress mouse model: an intraperitoneal injection of lipopolysaccharide (LPS) into neonatal mice was performed on postnatal days 7–9 (P7-P9) and inescapable foot shock (IFS) administration in adolescent was used as a later-life challenge. Our study shows that compared with mice that were only exposed to the LPS or IFS, the "two-hit" stress mice developed more severe depression/anxiety-like behaviors and social disability. We detected the levels of PDCD4 in the hippocampus of adolescent mice and found that they were significantly increased in "two-hit" stress mice. The results of immunohistochemical staining and Sholl analysis showed that the number of microglia in the hippocampus of "two-hit" stress mice significantly increased, with morphological changes, shortened branches, and decreased numbers. However, knocking down PDCD4 can prevent the number and morphological changes of microglia induced by ELS. In addition, we confirmed through the Golgi staining and immunohistochemical staining results that knocking down PDCD4 can ameliorate ELS-induced synaptic plasticity damage. Mechanically, the knockdown of PDCD4 exerts neuroprotective effects, possibly via the mediation of BDNF/AKT/CREB signaling. Combined, these results suggest that PDCD4 may play an important role in the ELS-induced susceptibility to depression and, thus, may become a therapeutic target for depressive disorders. • ELS aggravates depressive behavior in adolescent mice. • ELS promotes increased synaptic plasticity impairment in adolescent mice. • PDCD4 expression was obviously up regulated in the hippocampus of ELS mice. • Knockdown of PDCD4 could ameliorate psychological and physiological disorders. • PDCD4 is involved in ELS-induced susceptibility to depressive disorders. [ABSTRACT FROM AUTHOR]

Circular RNAs (circRNAs) are highly enriched in the brain and involved in many types of central nervous system pathologies. Herein, this study aimed to investigate the role and mechanism of circ_0007290 in ischemic stroke. The oxygen-glucose deprivation (OGD) model was established with the HCN-2 cells in vitro. Levels of genes and proteins was detected by quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot. In vitro experiments were conducted using cell counting kit-8 (CCK-8) assay, EdU (5-ethynyl-2'-deoxyuridine) assay, flow cytometry and ELISA, respectively. The levels of lactate dehydrogenase (LDH) were measured using the commercial kit. RNA pull-down and dual-luciferase reporter assay were used to identify the target relationship between miR-496 and circ_0007290 or PDCD4 (programmed cell death protein 4). Circ_0007290 expression was elevated in acute ischemic stroke (AIS) patients and OGD-induced cell injury model. OGD stimulation induced neuronal apoptosis, promoted LDH release, and enhanced inflammation in HCN-2 cells, which all were reversed by the knockdown of circ_0007290. Mechanistically, circ_0007290 served as a sponge for miR-496 to relieve the repression of miR-496 on the expression of its target PDCD4. Moreover, miR-496 inhibition or PDCD4 overexpression abolished the inhibitory effects of circ_0007290 knockdown OGD-evoked neuronal injury. Knockdown of circ_0007290 alleviated OGD-induced neuronal injury by regulating miR-496/PDCD4 axis, providing a novel insight into the pathology of ischemic stroke. [ABSTRACT FROM AUTHOR]

Recent studies have shown that programmed cell death 4 (PDCD4) modulates distinct signal transduction pathways in different pathological conditions. Despite acute and chronic immune responses elicited by ischemia contributing to the functional deterioration of the kidney, the contributions and mechanisms of PDCD4 in acute kidney injury (AKI) have remained unclear. Using two murine AKI models including renal ischemia/reperfusion injury (IRI) and cisplatin-induced AKI, we found that PDCD4 deficiency markedly ameliorated renal dysfunction and inflammatory responses in AKI mice. Consistently, upregulation of PDCD4 was also confirmed in the kidneys from patients with biopsy confirmed acute tubular necrosis from a retrospective cohort study. Moreover, we found that overexpression of Fgr, a member of the tyrosine kinase family, dramatically aggravated renal injury and counteracted the protective effects of PDCD4 deficiency in AKI mice. We discovered that FGR upregulated NOTCH1 expression through activating STAT3. Most importantly, we further found that systemic administration of ponatinib, a tyrosine kinase inhibitor, significantly ameliorated AKI in mice. In summary, we identified that PDCD4 served as an important regulator, at least in part, of FGR/NOTCH1-mediated tubular apoptosis and inflammation in AKI mice. Furthermore, our findings suggest that ponatinib-mediated pharmacologic targeting of this pathway had therapeutic potential for mitigating AKI.

Objective To observe the methylation status of the promoter region of the tumor suppressor gene PDCD4 in gastric cancer tissues and its effect on the expression level of PDCD4, and to explore its clinical significance. Methods The protein expression of PDCD4 in gastric cancer tissues was detected by immunohistochemistry (IHC) and Western blot; the mRNA expression of PDCD4 was detected by RT-PCR; the methylation level of PDCD4 promoter region was detected by MSP. The correlation between PDCD4 expression, promoter methylation level and clinicopathological characteristics of gastric cancer patients was analyzed. Results The expression levels of PDCD4 protein and mRNA in gastric cancer tissues were significantly decreased (P < 0.05), and the methylation of PDCD4 was significantly enhanced (P < 0.05). Deficiency of PDCD4 protein expression is closely correlated with the differentiation, clinical stage and lymph node metastasis of gastric cancer (P < 0.05); hypermethylation of PDCD4 is closely correlated with lymph node metastasis and clinical stage of gastric cancer (P < 0.05). The methylation level of PDCD4 was negatively correlated with the protein and mRNA expression levels of PDCD4 (P < 0.05). Conclusion The expression of PDCD4 in gastric cancer tissues is significantly decreased and correlated with the development of gastric cancer. Hypermethylation of CpG island in promoter region may be the reason for the deficiency of PDCD4 expression.

Objective: The aim of this study was to investigate gender differences after renal ischemia-reperfusion injury in mice and the effects of androgen receptor (AR) and microRNA-21 (miR-21) on apoptosis in renal ischemia-reperfusion injury.Methods: Renal ischemia-reperfusion injury model was induced by 45 min of bilateral renal artery ischemia and reperfusion. BALB/c mice were randomly divided into groups according to different experimental protocols. The levels of renal function were evaluated by serum creatinine and blood urea nitrogen. TUNEL staining was used to analyze the pathological changes and apoptosis levels of renal tissue, and western blotting and qPCR were used to detect the expressions of miR-21, AR, PDCD4 and caspase3.Results: After renal ischemia-reperfusion injury in mice with different genders, the levels of plasma urea nitrogen and creatinine in female and male mice increased, the histopathological score increased, and TUNEL staining in renal tissue indicated increased apoptosis. The expressions of miR-21, PDCD4, and active caspase-3 protein were up-regulated. The above trend was more pronounced in male mice, and a significant decrease in AR mRNA expression was detected. Silencing the expression of AR aggravated the decline of renal function and renal tubular injury after renal ischemia in mice. The expression of PDCD4 and active caspase-3 increased, while the level of miR-21 was correspondingly decreased. Up-regulation of miR-21 expression by pre-miR-21 could negatively regulate PDCD4, reduce the expression level of active caspase3, and yet induce AR expression accordingly. MiR-21 alleviated renal ischemia-reperfusion injury by inhibiting renal tubular epithelial cell apoptosis. The effect of antagomiR-21 was the opposite, which aggravated renal ischemia-reperfusion injury.Conclusion: There are gender differences in renal ischemia-reperfusion injury. Male mice are more susceptible to renal ischemia-reperfusion injury than female. Silencing AR expression or down-regulating the level of miR-21 can promote the expression of PDCD4 and apoptosis protein caspase3, thereby aggravating ischemia-reperfusion injury in mice. The protective effect of AR and miR-21 in renal ischemia-reperfusion injury has a certain synergy.

The loss of melanocytes in vitiligo is associated with architectural, transcriptional, and cellular perturbations of keratinocytes and manifests as a reduced proliferation potential in vitro and delayed re‐epithelialization in vivo. To understand the molecular mechanisms underlying this delay, microRNA (miRNA) profiling was performed on split skin biopsies collected on Day 1 (basal level) and Day 14 (wound re‐epithelialization) from nonlesional (NL) and lesional (L) skin of five subjects with stable nonsegmental vitiligo and 129 miRNAs were found to be differentially regulated between the NL and L healed epidermis. miR‐21‐5p, expressed at comparable levels on NL and L Day 1 samples, demonstrated significant upregulation during re‐epithelialization. However, the extent of its upregulation was relatively lower in L (10 times compared to Day 1) as compared to NL skin (17 times compared to Day 1). The overexpression of miR‐21 in keratinocytes led to a significant increase in the expression of proliferation markers (Ki67 and MCM6 messenger RNA, Ki67 positivity), along with an increase in keratinocyte migration. Using a small interfering RNA mediated knockdown approach, we further demonstrated that miR‐21‐5p mediates its effects by suppressing the expression of programmed cell death 4 (PDCD4) and mammary serine protease inhibitor (Maspin), both tumor‐suppressor genes. Investigation of clinical samples corroborated the lower miR‐21 levels and a higher expression of PDCD4 and Maspin in L Day 14 compared to the NL Day 14 epidermis. In conclusion, this study revealed that a relatively lower upregulation of miR‐21‐5p in L skin leads to significantly higher levels of PDCD4 and Maspin, delaying wound re‐epithelialization by reducing the proliferation and migration of keratinocytes. [ABSTRACT FROM AUTHOR]