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Colorectal cancer (CRC) is one of the most common types of malignant tumor. Many genetic factors have been proved to show high association with the occurrence and development of CRC and many mutations are detected in CRC. PTPN4/PTP‐MEG1 is a widely expressed non–receptor protein tyrosine phosphatase. Over the past three decades, PTPN4 has been demonstrated in the literature to participate in many biological processes. In this study, we identified a nonsense mutation of PTPN4 with a mutation ratio of 90.90% from 1 case of rectal cancer, leading to loss of function in PTPN4 gene. Several somatic mutations occurred in 5/137 rectal cancer samples from The Cancer Genome Atlas Rectum Adenocarcinoma (TCGA READ) database. Interestingly, we found that PTPN4 negative cytoplasm staining was more prone to lymphatic metastasis (N = 50, P = 0.0153) and low expression of PTPN4 in rectal cancer was highly associated with poor prognosis. Overexpression of PTPN4 suppressed the cell growth, and moreover, the loss of PTPN4 accelerated cell growth and boosted clonogenicity of CRC cells. Furthermore, we revealed that the deletion of PTPN4 promoted the tumor formation of NCM460 cells in vivo. In terms of the molecular mechanism, we demonstrated that PTPN4 dephosphorylates pSTAT3 at the Tyr705 residue with a direct interaction and suppresses the transcriptional activity of STAT3. In summary, our study revealed a novel mechanism that the tumorigenesis of colorectal cancer might be caused by the loss of PTPN4 through activating STAT3, which will broaden the therapy strategy for anti–rectal cancer in the future. In our study, we identified a nonsense mutation of PTPN4 with mutation ratio of 90.90% from 1 case of rectal cancer. Overexpression of PTPN4 suppressed the growth of colorectal cancer cells. PTPN4 dephosphorylates pSTAT3 at the Tyr705 residue with a direct interaction and depresses the transcriptional activity of STAT3.

Haihong Deng,1,* Qisen Fan,2,* Lichao Huang,1 Wenbo Ouyang,1 Wendian Zhu3 1Department of Anesthesiology, The First People’s Hospital of Zhaoqing, Zhaoqing City, Guangdong Province, People’s Republic of China; 2Department of Anesthesiology, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou City, Guangdong Province, People’s Republic of China; 3Department of Hepatobiliary Surgery, The First People’s Hospital of Zhaoqing, Zhaoqing City, Guangdong Province, People’s Republic of China*These authors contributed equally to this workCorrespondence: Wendian Zhu, Department of Hepatobiliary Surgery, The First People’s Hospital of Zhaoqing, NO. 9 Donggang East Road, Duanzhou District, Zhaoqing City, Guangdong Province, People’s Republic of China, Email Zq2860676@163.comBackground: Myocardial ischemia/reperfusion (I/R) injury significantly impacts the recovery of ischemic heart disease patients. Non-coding RNAs, including miRNAs, have been increasingly recognized for their roles in regulating cardiomyocyte responses to hypoxia/reoxygenation (H/R) injury. miR-181c-5p, in particular, has been implicated in inflammatory and apoptotic processes, suggesting its potential involvement in exacerbating cellular damage.Methods: This study combined bioinformatic and experimental techniques to investigate myocardial injury. Gene expression data from the GEO database were analyzed, and HL-1 cardiomyocytes were used in a hypoxia/reoxygenation model to mimic reperfusion injury. Various molecular techniques have been applied to explore the underlying mechanisms, while statistical analyses have identified potential biomarkers and therapeutic targets.Results: This study revealed significant upregulation of miR-181c-5p in cardiomyocyte H/R injury models, which inversely affected PTPN4 expression and activated the TLR4/NF-κB signaling pathway. Overexpression of PTPN4 inhibited this pathway. Notably, circ₀001084 was identified as absorbing miR-181c-5p, reducing its interaction with PTPN4 and subsequent pathway activation. This suggests a novel therapeutic pathway for myocardial I/R injury treatment, highlighting the interplay between non-coding RNAs and cellular stress responses.Conclusion: circ₀001084 acts as a competing endogenous RNA for miR-181c-5p, enhancing PTPN4 expression and inhibiting the TLR4/NF-κB signaling pathway. These findings offer insights into the molecular mechanisms of myocardial I/R injury and potential therapeutic targets in ischemic heart disease.Keywords: Myocardial, Circ₀001084/miR-181c-5p/PTPN4 axis, Cardiomyocyte hypoxia, Reoxygenation, TLR4/NF-κB pathway

Adipose-derived stem cells (ADSCs) have been demonstrated to improve the microenvironment after a stroke. Increasing studies have confirmed that hypoxia pretreatment of ADSCs resulted in a better therapeutic effect, but the mechanism of treatment is unclear. We isolated ADSCs and exosomes. Then, constructed a middle cerebral artery occlusion (MCAO) mice model. High-throughput sequencing was used to identify the differential expression of circRNA. Immunofluorescence and ELISAs were used to detect the therapeutic effects of ADSC exosomes on MCAO. The luciferase reporter assay was used to detect the interaction relationships among circRNA-Ptpn4, miR-153-3p, and Nrf2. This study showed that exosomes from hypoxia pretreatment of ADSCs had significant effects in promoting functional recovery following in vivo MCAO, through suppressed inflammatory factor expression, and shifting the microglial from M1 to M2 polarization activation. The results showed that circRNA-Ptpn4 was highly expressed during hypoxia pretreatment of ADSCs exosomes. Exosomes from circ-Ptpn4-modified ADSCs had a greater ability to promote functional recovery. The circ-Ptpn4 delivered from ADSC exosomes induced microglia/macrophage polarization from M1 to M2 by suppressing miR-153-3p and enhancing Nrf2 expressions. Taken together, the results showed that exosomes from circRNA-Ptpn4 modified ADSC treatment repaired nerve damage caused by cerebral infarction by inducing microglial M1/M2 polarization.

Uremic encephalopathy (UE) poses a significant challenge in neurology, leading to the need to investigate the involvement of non-coding RNA (ncRNA) in its development. This study employed ncRNA-seq and RNA-seq approaches to identify fundamental ncRNAs, specifically circRNA and miRNA, in the pathogenesis of UE using a mouse model. In vitro and in vivo experiments were conducted to explore the circRNA-PTPN4/miR-301a-3p/FOXO3 axis and its effects on blood–brain barrier (BBB) function and cognitive abilities. The research revealed that circRNA-PTPN4 binds to and inhibits miR-301a-3p, leading to an increase in FOXO3 expression. This upregulation results in alterations in the transcriptional regulation of ZO-1, affecting the permeability of human brain microvascular endothelial cells (HBMECs). The axis also influences the growth, proliferation, and migration of HBMECs. Mice with UE exhibited cognitive deficits, which were reversed by overexpression of circRNA-PTPN4, whereas silencing FOXO3 exacerbated these deficits. Furthermore, the uremic mice showed neuronal loss, inflammation, and dysfunction in the BBB, with the expression of circRNA-PTPN4 demonstrating therapeutic effects. In conclusion, circRNA-PTPN4 plays a role in promoting FOXO3 expression by sequestering miR-301a-3p, ultimately leading to the upregulation of ZO-1 expression and restoration of BBB function in mice with UE. This process contributes to the restoration of cognitive abilities.1. The circRNA-PTPN4/miR-301a-3p/FOXO3 axis is identified as a key regulator of blood–brain barrier integrity and cognitive function in uremic encephalopathy.2. circRNA-PTPN4 sequestration of miR-301a-3p enhances FOXO3 expression, leading to upregulation of ZO-1 and improved endothelial permeability.3. Overexpression of circRNA-PTPN4 in uremic mice restores cognitive abilities and reduces neuronal loss and inflammatory infiltration.

Background Protein tyrosine phosphatase, non-receptor type 4 ( PTPN4 ) is a gene involved in glutamate downstream signaling contributing to cerebral maturation. Loss-of-function of this gene has been reported in patients showing various neurodevelopmental disorders, although the PTPN4 gene is not clearly considered a disease-causing gene in the Online Mendelian Inheritance in Man catalogue. Case presentation Here, we report the case of a 7-year-old white boy with a homogeneous, heterozygous, 170 kb chromosomal deletion encompassing several exons of the PTPN4 gene. The mutation was transmitted by his father, who had an undiagnosed communication disorder. The patient was referred to a day care unit for complex neurodevelopmental disorders and a suspicion of autism spectrum disorder. He had a severe communication disorder associated with sensory integration issues, anxiety, and elimination disorder. During his 4 years in the day care hospital, he received educational, creative, and academic group activities and specific re-education. Group activities help generalize the newly acquired developmental skills by providing social reinforcers and opportunities for positive peer interactions. In turn, achieving social activities positively influences the patient’s self-esteem, emotional insight, and motivation to make new progress. Conclusion Despite a severe communication disorder associated with sensory integration issues, anxiety, and elimination disorder, a diagnosis of autism spectrum disorder was ruled out, and remarkable progress was observed, which allowed our patient to attend same-age mainstream schools with personalized support at discharge. This case illustrates the effect of dimensional interventions to limit developmental impairments in a context of PTPN4 mutation and the benefit of providing an enriched environment in combination with individual re-education to improve developmental outcomes.

Background Abnormal protein localization due to disrupted nucleoplasmic transport is common in tumor cells, but its mechanisms are not well understood. Nuclear pore complexes and nuclear transporter proteins are crucial for protein transport between the nucleus and cytoplasm. Evidence increasingly shows that abnormal expression of karyopherin family proteins disrupts protein translocation, affecting processes like cell differentiation, proliferation, apoptosis, and transcriptional regulation. However, their functions and roles in ovarian cancer remain unclear. Methods The expression level of KPNA5 in ovarian cancer tissues and cells was detected by IHC, Western blot, and qPCR. CCK‐8 and colony formation assays were used to assess cell proliferation ability. Transwell assay was conducted to determine cell migration and invasion capacity. A xenograft model was used to assess the effect of KPNA5 on tumor growth in vivo. Results KPNA5 expression is downregulated in ovarian cancer (OC) tissues. Low KPNA5 levels were associated with poor survival in OC patients, validated by an OC tissue sample cohort. Overexpression of KPNA5 significantly suppressed OC cell proliferation, tumor growth, and invasion in both in vitro and in vivo studies. Mechanistically, KPNA5 recognizes nuclear localization signals (NLSs) in PTPN4, mediating its nuclear transport and inhibiting STAT3 phosphorylation and its downstream signaling pathway. Similarly, PTPN4 overexpression reduced OC cell viability and invasion, also suppressing STAT3 phosphorylation. Conclusions Our findings identify KPNA5 as a tumor suppressor in OC, presenting a potential therapeutic target for OC treatment.

Myocardial ischemia/reperfusion (I/R) injury significantly impacts the recovery of ischemic heart disease patients. Non-coding RNAs, including miRNAs, have been increasingly recognized for their roles in regulating cardiomyocyte responses to hypoxia/reoxygenation (H/R) injury. miR-181c-5p, in particular, has been implicated in inflammatory and apoptotic processes, suggesting its potential involvement in exacerbating cellular damage. This study combined bioinformatic and experimental techniques to investigate myocardial injury. Gene expression data from the GEO database were analyzed, and HL-1 cardiomyocytes were used in a hypoxia/reoxygenation model to mimic reperfusion injury. Various molecular techniques have been applied to explore the underlying mechanisms, while statistical analyses have identified potential biomarkers and therapeutic targets. This study revealed significant upregulation of miR-181c-5p in cardiomyocyte H/R injury models, which inversely affected PTPN4 expression and activated the TLR4/NF-κB signaling pathway. Overexpression of PTPN4 inhibited this pathway. Notably, circ_0001084 was identified as absorbing miR-181c-5p, reducing its interaction with PTPN4 and subsequent pathway activation. This suggests a novel therapeutic pathway for myocardial I/R injury treatment, highlighting the interplay between non-coding RNAs and cellular stress responses. circ_0001084 acts as a competing endogenous RNA for miR-181c-5p, enhancing PTPN4 expression and inhibiting the TLR4/NF-κB signaling pathway. These findings offer insights into the molecular mechanisms of myocardial I/R injury and potential therapeutic targets in ischemic heart disease.

Background Cognitive dysfunction (CD) is common among patients with the autoimmune disease systemic lupus erythematosus (SLE). Anti-ribosomal P autoantibodies associate with this dysfunction and have neuropathogenic effects that are mediated by cross-reacting with neuronal surface P antigen (NSPA) protein. Elucidating the function of NSPA can then reveal CD pathogenic mechanisms and treatment opportunities. In the brain, NSPA somehow contributes to glutamatergic NMDA receptor (NMDAR) activity in synaptic plasticity and memory. Here we analyze the consequences of NSPA absence in KO mice considering its structural features shared with E3 ubiquitin ligases and the crucial role of ubiquitination in synaptic plasticity. Results Electrophysiological studies revealed a decreased long-term potentiation in CA3-CA1 and medial perforant pathway-dentate gyrus (MPP-DG) hippocampal circuits, reflecting glutamatergic synaptic plasticity impairment in NSPA-KO mice. The hippocampal dentate gyrus of these mice showed a lower number of Arc-positive cells indicative of decreased synaptic activity and also showed proliferation defects of neural progenitors underlying less adult neurogenesis. All this translates into poor spatial and recognition memory when NSPA is absent. A cell-based assay demonstrated ubiquitination of NSPA as a property of RBR-type E3 ligases, while biochemical analysis of synaptic regions disclosed the tyrosine phosphatase PTPMEG as a potential substrate. Mice lacking NSPA have increased levels of PTPMEG due to its reduced ubiquitination and proteasomal degradation, which correlated with lower levels of GluN2A and GluN2B NMDAR subunits only at postsynaptic densities (PSDs), indicating selective trafficking of these proteins out of PSDs. As both GluN2A and GluN2B interact with PTPMEG, tyrosine (Tyr) dephosphorylation likely drives their endocytic removal from the PSD. Actually, immunoblot analysis showed reduced phosphorylation of the GluN2B endocytic signal Tyr1472 in NSPA-KO mice. Conclusions NSPA contributes to hippocampal plasticity and memory processes ensuring appropriate levels of adult neurogenesis and PSD-located NMDAR. PTPMEG qualifies as NSPA ubiquitination substrate that regulates Tyr phosphorylation-dependent NMDAR stability at PSDs. The NSPA/PTPMEG pathway emerges as a new regulator of glutamatergic transmission and plasticity and may provide mechanistic clues and therapeutic opportunities for anti-P-mediated pathogenicity in SLE, a still unmet need.

PTPN4 is a widely expressed non-receptor protein tyrosine phosphatase. Although its overexpression inhibits cell growth, the proteins with which it interacts to regulate cell growth are unknown. In this study, we identified CrkI as a PTPN4-interacting protein using a yeast two-hybrid, and confirmed this interaction using in vitro GST pull-down and co-immunoprecipitation and co-localization assays. We further determined the interactional regions as the SH3 domain of CrkI and the proline-rich region between amino acids 462 and 468 of PTPN4. Notably, overexpression of PTPN4 inhibits CrkI-mediated proliferation and wound healing of HEK293T cells, while knockdown of PTPN4 by siRNA in Hep3B cells enhances CrkI-mediated cell growth and motility. Moreover, our data show that ectopic expression of PTPN4 reduces the phosphorylation level of CrkI in HEK293T cells. These findings suggest that PTPN4 negatively regulates cell proliferation and motility through dephosphorylation of CrkI.