Receptor Protein Tyrosine Phosphatase Research Articles

Integrin α6β4 Upregulates PTPRZ1 Through UCHL1-Mediated Hif-1α Nuclear Accumulation to Promote Triple-Negative Breast Cancer Cell Invasive Properties.

Integrin α6β4 drives triple-negative breast cancer (TNBC) aggressiveness through the transcriptional regulation of key genes. Here, we investigated how integrin α6β4 regulates protein tyrosine phosphatase receptor type Z1 (PTPRZ1). Using stable re-expression of integrin β4 (ITGB4) in cells naturally devoid of integrin α6β4 or knockdown or knockout (KO) of ITGB4, we found that integrin α6β4 regulates PTPRZ1 expression. To gain mechanistic insight, we focused on Hif-1α due to the impact of integrin α6β4 on a hypoxia-associated signature. We found that nuclear localization of Hif-1α, but not Hif-2α, was substantially enhanced with integrin α6β4 signaling. Hif-1α knockdown by shRNA or chemical inhibition decreased PTPRZ1 expression, while chemical activation of Hif-1α increased it. Upstream of Hif-1α, integrin α6β4 upregulates UCHL1 to stabilize Hif-1α and ultimately regulate PTPRZ1. Inhibition of UCHL1 and PTPRZ1 dramatically decreases integrin α6β4-mediated cell migration and three-dimensional invasive growth. Finally, public breast cancer database analyses demonstrated that ITGB4 correlates with PTPRZ1 and that high expression of ITGB4, UCHL1, HIF1A, and PTPRZ1 associated with decreased overall survival, distant metastasis free survival, post progression survival, and relapse-free survival. In summary, these findings provide a novel function of integrin α6β4 in promoting tumor invasive phenotypes through UCHL1-Hif-1α-mediated regulation of PTPRZ1.

Effects of hyperglycemia on airway epithelial barrier function in WT and CF 16HBE cells

Cystic fibrosis related diabetes (CFRD), the main co-morbidity in cystic fibrosis (CF), is associated with higher rates of lung function decline. We hypothesize that airway epithelial barrier function is impaired in CF and is further exacerbated under hyperglycemia, worsening pulmonary outcomes. Using 16HBE cells, we studied the effects of hyperglycemia in airway epithelial barrier function. Results show increased paracellular dye flux in CF cells in response to insulin under hyperglycemia. Gene expression experiments identified claudin-4 (CLDN4) as a key tight junction protein dysregulated in CF cells. CLDN4 protein localization by confocal microscopy showed that CLDN4 was tightly localized at tight junctions in WT cells, which did not change under hyperglycemia. ln contrast, CLDN4 was less well-localized in CF cells at normal glucose and localization was worsened under hyperglycemia. Treatment with highly effective modulator compounds (ETI) reversed this trend, and CFTR rescue was not affected by insulin or hyperglycemia. Bulk RNA sequencing showed differences in transcriptional responses in CF compared to WT cells under normal or high glucose, highlighting promising targets for future investigation. One of these targets is protein tyrosine phosphatase receptor type G (PTPRG), which has been previously found to play a role in defective Akt signaling and insulin resistance.

Pleiotrophin Activates cMet- and mTORC1-Dependent Protein Synthesis through PTPRZ1-The Role of ανβ3 Integrin.

Pleiotrophin (PTN) is a secreted factor that regulates endothelial cell migration through protein tyrosine phosphatase receptor zeta 1 (PTPRZ1) and αvβ3 integrin. Genetic deletion of Ptprz1 results in enhanced endothelial cell proliferation and migration, due to the decreased expression of β3 integrin and the subsequent, enhanced cMet phosphorylation. In the present study, we investigated the effect of PTN and PTPRZ1 on activating the mTORC1 kinase and protein synthesis and identified part of the implicated signaling pathway in endothelial cells. PTN or genetic deletion of Ptprz1 activates protein synthesis in a mTORC1-dependent manner, as shown by the enhanced phosphorylation of the mTORC1-downstream targets ribosomal protein S6 kinase 1 (SK61) and 4E-binding protein 1 (4EBP1) and the upregulation of HIF-1α. The cMet tyrosine kinase inhibitor crizotinib abolishes the stimulatory effects of PTN or PTPRZ1 deletion on mTORC1 activation and protein synthesis, suggesting that mTORC1 activation is downstream of cMet. The mTORC1 inhibitor rapamycin abolishes the stimulatory effect of PTN or PTPRZ1 deletion on endothelial cell migration, suggesting that mTORC1 is involved in the PTN/PTPRZ1-dependent cell migration. The αvβ3 integrin blocking antibody LM609 and the peptide PTN112-136, both known to bind to ανβ3 and inhibit PTN-induced endothelial cell migration, increase cMet phosphorylation and activate mTORC1, suggesting that cMet and mTORC1 activation are required but are not sufficient to stimulate cell migration. Overall, our data highlight novel aspects of the signaling pathway downstream of the PTN/PTPRZ1 axis that regulates endothelial cell functions.

7753 Anoctamin 4 in the Area Postrema Regulates Glucose and Energy Homeostasis

Abstract Disclosure: L. Tu: None. Y. Xu: None. Located on the floor of the 4th ventricle within the dorsal surface of the medulla oblongata, the area postrema (AP) is a circumventricular organ where a proper blood-brain barrier is missing. Numerous studies reveal that neurons in the AP are implicated into suppression of food intake (e.g., glucagon-like peptide 1 (GLP-1)-mediated anorexia), but the role of AP neurons in whole-body glucose homeostasis is less investigated. Here we identified and fully characterized the physiological functions of anoctamin-4 (Ano4, a calcium activated chloride channel)1 in the AP. CRISPR-mediated deletion of Ano4 in the AP caused a lower body weight and reduced blood glucose, concurrent with an improved glucose tolerance and increased insulin sensitivity. Chemogenetic activation of Ano4-expressing neurons in the AP (APAno4) increased food intake and blood glucose, and did not induce conditioned flavor avoidance. Both Ano4 neurons and non-Ano4 neurons (i.e., neurons do not express Ano4) sent projections to the lateral parabrachial nucleus (LPBN). Optogenetic stimulation of APAno4 ◊ LPBN circuit promoted feeding behavior and increased blood glucose, whereas stimulation of APnon-Ano4 ◊ LPBN circuit inhibited food intake and did not influence glucose homeostasis. Finally, RNAscope studies reveal that 45.7% of APAno4 neurons are glutamatergic neurons, and 41.8% of them are GABAergic neurons. Furthermore, APAno4 neurons showed only a 2.6% overlap with Glp-1r-expressing neurons in the AP, but had a 60.8% co-localization with protein tyrosine phosphatase receptor δ2, which serves as orexigenic asprosin receptor. Together, our results indicate that Ano4 neurons in the AP are the first reported orexigenic neurons, and represent potential therapeutic targets for human diseases with glucose imbalance and abnormal feeding behavior. Reference: (1) Tu, L. et al. Anoctamin 4 channel currents activate glucose-inhibited neurons in the mouse ventromedial hypothalamus during hypoglycemia. J Clin Invest 133,14. (2023). (2) Mishra, I. et al. Protein tyrosine phosphatase receptor δ serves as the orexigenic asprosin receptor. Cell Metab 34, 549-563. (2022). Presentation: 6/2/2024

9207 Anoctamin 4 in the Area Postrema Regulates Glucose and Energy Homeostasis

Abstract Disclosure: L. Tu: None. Y. Xu: None. Located on the floor of the 4th ventricle within the dorsal surface of the medulla oblongata, the area postrema (AP) is a circumventricular organ where a proper blood-brain barrier is missing. Numerous studies reveal that neurons in the AP are implicated into suppression of food intake (e.g., glucagon-like peptide 1 (GLP-1)-mediated anorexia), but the role of AP neurons in whole-body glucose homeostasis is less investigated. Here we identified and fully characterized the physiological functions of anoctamin-4 (Ano4, a calcium activated chloride channel)1 in the AP. CRISPR-mediated deletion of Ano4 in the AP caused a lower body weight and reduced blood glucose, concurrent with an improved glucose tolerance and increased insulin sensitivity. Chemogenetic activation of Ano4-expressing neurons in the AP (APAno4) increased food intake and blood glucose, and did not induce conditioned flavor avoidance. Both Ano4 neurons and non-Ano4 neurons (i.e., neurons do not express Ano4) sent projections to the lateral parabrachial nucleus (LPBN). Optogenetic stimulation of APAno4 ◊ LPBN circuit promoted feeding behavior and increased blood glucose, whereas stimulation of APnon-Ano4 ◊ LPBN circuit inhibited food intake and did not influence glucose homeostasis. Finally, RNAscope studies reveal that 45.7% of APAno4 neurons are glutamatergic neurons, and 41.8% of them are GABAergic neurons. Furthermore, APAno4 neurons showed only a 2.6% overlap with Glp-1r-expressing neurons in the AP, but had a 60.8% co-localization with protein tyrosine phosphatase receptor δ2, which serves as orexigenic asprosin receptor. Together, our results indicate that Ano4 neurons in the AP are the first reported orexigenic neurons, and represent potential therapeutic targets for human diseases with glucose imbalance and abnormal feeding behavior. Reference: (1) Tu, L. et al. Anoctamin 4 channel currents activate glucose-inhibited neurons in the mouse ventromedial hypothalamus during hypoglycemia. J Clin Invest 133,14. (2023). (2) Mishra, I. et al. Protein tyrosine phosphatase receptor δ serves as the orexigenic asprosin receptor. Cell Metab 34, 549-563. (2022). Presentation: 6/2/2024

Protein tyrosine phosphatase receptor type O serves as a key regulator of insulin resistance-induced α-synuclein aggregation in Parkinson’s disease

Insulin resistance (IR) was found to be a critical element in the pathogenesis of Parkinson’s disease (PD), facilitating abnormal α-synuclein (α-Syn) aggregation in neurons and thus promoting PD development. However, how IR contributes to abnormal α-Syn aggregation remains ill-defined. Here, we analyzed six PD postmortem brain transcriptome datasets to reveal module genes implicated in IR-mediated α-Syn aggregation. In addition, we induced IR in cultured dopaminergic (DA) neurons overexpressing α-Syn to identify IR-modulated differentially expressed genes (DEGs). Integrated analysis of data from PD patients and cultured neurons revealed 226 genes involved in α-Syn aggregation under IR conditions, of which 53 exhibited differential expression between PD patients and controls. Subsequently, we conducted an integrated analysis of the 53 IR-modulated genes employing transcriptome data from PD patients with different Braak stages and DA neuron subclasses with varying α-Syn aggregation scores. Protein tyrosine phosphatase receptor type O (PTPRO) was identified to be closely associated with PD progression and α-Syn aggregation. Experimental validation in a cultured PD cell model confirmed that both mRNA and protein of PTPRO were reduced under IR conditions, and the downregulation of PTPRO significantly facilitated α-Syn aggregation and cell death. Collectively, our findings identified PTPRO as a key regulator in IR-mediated α-Syn aggregation and uncovered its prospective utility as a therapeutic target in PD patients with IR.

Analysis and identification of mRNAsi‑related expression signatures via RNA sequencing in lung cancer.

High stemness index scores are associated with poor survival in patients with lung cancer. Studies on the mRNA expression-based stemness index (mRNAsi) are typically conducted using tumor tissues; however, mRNAsi-related expression signatures based on cell-free RNA (cfRNA) are yet to be comprehensively investigated. The present study aimed to elucidate the gene expression profiles of tumor stemness in lung cancer tissues and corresponding cfRNAs in blood, and to assess their links with immune infiltration. Tumor tissue, paracancerous tissue, peripheral blood and lymph node samples were collected from patients with stage I-III non-small cell lung cancer and RNA sequencing was performed. The TCGAbiolinks package was used to calculate the mRNAsi for each of these four types of sample. Weighted gene co-expression network analysis and differentially expressed gene analyses were performed to investigate mRNAsi-related genes, and pathway enrichment analysis was performed using the Kyoto Encyclopedia of Genes and Genomes (KEGG) orthology-based annotation system. In addition, the STAR-Fusion tool was used to detect fusion variants, and CIBERSORT was used to analyze the correlations of stemness signatures in tissues and blood with immune cell infiltration. The mRNAsi values in peripheral blood and lymph nodes were found to be higher than those in cancer tissues. 'Hematopoietic cell lineage' was the only KEGG pathway enriched in mRNAsi-related genes in both lung cancer tissues and peripheral blood. In addition, the protein tyrosine phosphatase receptor type C associated protein gene was the only gene commonly associated with the mRNAsi in these two types of sample. The expression of mRNAsi-related genes was increased in the dendritic and Treg cells in tumor tissues, but was elevated in Treg and CD8 cells in the blood. In conclusion, cfRNAs in the blood exhibit unique stemness signatures that have potential for use in the diagnosis of lung cancer.

PTPRJ is a negative regulator of insulin signaling in neuronal cells, impacting protein biosynthesis, and neurite outgrowth.

Central insulin resistance has been linked to the development of neurodegenerative diseases and mood disorders. Various proteins belonging to the enzyme family of protein tyrosine phosphatases (PTPs) act as inhibitors of insulin signaling. Protein tyrosine phosphatase receptor type J (PTPRJ) has been identified as a negative regulator in insulin signaling in the periphery. However, the impact of PTPRJ on insulin signaling and its functional role in neuronal cells is largely unknown. Therefore, we generated a Ptprj knockout (KO) cell model in the murine neuroblast cell line Neuro2a by CRISPR-Cas9 gene editing. Ptprj KO cells displayed enhanced insulin signaling, as shown by increased phosphorylation of the insulin receptor (INSR), IRS-1, AKT, and ERK1/2. Further, proximity ligation assays (PLA) revealed both direct interaction of PTPRJ with the INSR and recruitment of this phosphatase to the receptor upon insulin stimulation. By RNA sequencing gene expression analysis, we identified multiple gene clusters responsible for glucose uptake and metabolism, and genes involved in the synthesis of various lipids being mainly upregulated under PTPRJ deficiency. Furthermore, multiple Ca2+ transporters were differentially expressed along with decreased protein biosynthesis. This was accompanied by an increase in endoplasmic reticulum (ER) stress markers. On a functional level, PTPRJ deficiency compromised cell differentiation and neurite outgrowth, suggesting a role in nervous system development. Taken together, PTPRJ emerges as a negative regulator of central insulin signaling, impacting neuronal metabolism and neurite outgrowth.

Identification of Sweetness Preference-Related Single-Nucleotide Polymorphisms for Polygenic Risk Scores Associated with Obesity.

Our study aimed to identify sweetness preference-associated single-nucleotide polymorphisms (SNPs), characterize the related genetic loci, and develop SNP-based polygenic risk scores (PRS) to analyze their associations with obesity. For genotyping, we utilized a pooled genome-wide association study (GWAS) dataset of 18,499 females and 10,878 males. We conducted genome-wide association analyses, functional annotation, and employed the weighted method to calculate the levels of PRS from 677 sweetness preference-related SNPs. We used Cox proportional hazards modeling with time-varying covariates to estimate age-adjusted and multivariable hazard ratios (HRs) and 95% confidence intervals (CIs) for obesity incidence. We also tested the correlation between PRS and environmental factors, including smoking and dietary components, on obesity. Our results showed that in males, the TT genotype of rs4861982 significantly increased obesity risk compared to the GG genotype in the Health Professionals Follow-up Study (HPFS) cohort (HR = 1.565; 95% CI, 1.122-2.184; p = 0.008) and in the pooled analysis (HR = 1.259; 95% CI, 1.030-1.540; p = 0.025). Protein tyrosine phosphatase receptor type O (PTPRO) was identified as strongly associated with sweetness preference, indicating a positive correlation between sweetness preference and obesity risk. Moreover, each 10 pack-year increment in smoking was significantly associated with an increased risk of obesity in the HPFS cohort (HR = 1.024; 95% CI, 1.000-1.048) in males but not in females. In conclusion, significant associations between rs4861982, sweetness preference, and obesity were identified, particularly among males, where environmental factors like smoking are also correlated with obesity risk.

Abstract P205: Single-nucleus Sequencing Reveals Endothelial Cell-specific Dysregulation in the Kidney in Multiple Models of Hypertension

The kidney plays a crucial role in the onset and progression of hypertension. To investigate the roles of different renal cell types in hypertension, we applied single-nucleus sequencing and spatial transcriptome sequencing to kidney samples from three well-established hypertension models: C57BL/6 mice treated with Ang II, the Dahl salt-sensitive (SS) rat on high-salt diets, and the spontaneously hypertensive rat (SHR), along with their respective controls including Sprague-Dawley (SD) and Wistar Kyoto (WKY) rats. Our dataset comprised 179,637 nuclei from 24 samples across 12 experimental conditions, identifying 17 major cell types including various epithelial cells, endothelial cells, vascular smooth muscle cells, fibroblasts, and immune cells. At baseline, differentially expressed genes between the SS and SD groups were specifically enriched in endothelial cell pathways related to vascular development. This included expression deficiencies in genes involved in angiogenesis in SS rats, such as Arhgap24 and Nox4. Compensatory expression changes in these genes were observed in the SS rats after a high-salt diet and in 26-week-old SHR, but not in their respective controls. These genes were also associated with multiple blood pressure-associated single-nucleotide polymorphisms (SNPs). Furthermore, changes in endothelial cell communication were most prominent upon stimuli, with impaired PTPRM (Protein Tyrosine Phosphatase Receptor Type M) signaling being a robust feature in hypertension models, involving angiogenic endothelial cells in the SS model and proliferating capillary endothelial cells in the SHR model. Our study highlights the critical role of renal endothelial cell angiogenic dysfunction in the pathogenesis of hypertension and suggests a link between specific renal endothelial cell subtype dysregulation and hypertension development.

Increased intestinal permeability and lipopolysaccharide contribute to swainsonine-induced systemic inflammation

Long-term consumption of swainsonine could be poisonous to livestock, including facilitating apoptosis by impairing lysosomal function and inhibiting autophagic degradation, leading to liver inflammation and even death in livestock. However, the mechanism by swainsonine induced systemic inflammatory responses remained unclear, especially the effects of swainsonine on intestinal permeability, lipopolysaccharide (LPS) level and oxidative stress response were unknown. In this study, swainsonine increased intestinal permeability as evidenced by the significant down-regulation of colonic goblet cells, Akkermansia muciniphila and intestinal tight junction protein Occludin, Claudin 1 and ZO-1, and the significant up-regulation of mRNA expression level of the intestinal permeability indicator protein tyrosine phosphatase receptor type H (Ptprh) in the ileum of mice. Simultaneously, the elevated LPS biosynthetic genes in intestinal microbiota and increased intestinal permeability facilitated more bacterial endotoxin LPS to enter the blood. High concentration of free-form LPS induced high levels of proinflammatory cytokines and oxidative stress response, thereby causing the systemic inflammation. These findings provided a new perspective on swainsonine-induced systemic inflammation, suggesting that intestinal permeability and free-form LPS level may be the potential trigger factors.

A molecular brain atlas reveals cellular shifts during the repair phase of stroke.

Ischemic stroke triggers a cascade of pathological events that affect multiple cell types and often lead to incomplete functional recovery. Despite advances in single-cell technologies, the molecular and cellular responses that contribute to long-term post-stroke impairment remain poorly understood. To gain better insight into the underlying mechanisms, we generated a single-cell transcriptomic atlas from distinct brain regions using a mouse model of permanent focal ischemia at one month post-injury. Our findings reveal cell- and region-specific changes within the stroke-injured and peri-infarct brain tissue. For instance, GABAergic and glutamatergic neurons exhibited upregulated genes in signaling pathways involved in axon guidance and synaptic plasticity, and downregulated pathways associated with aerobic metabolism. Using cell-cell communication analysis, we identified increased strength in predicted interactions within stroke tissue among both neural and non-neural cells via signaling pathways such as those involving collagen, protein tyrosine phosphatase receptor, neuronal growth regulator, laminin, and several cell adhesion molecules. Furthermore, we found a strong correlation between mouse transcriptome responses after stroke and those observed in human nonfatal brain stroke lesions. Common molecular features were linked to inflammatory responses, extracellular matrix organization, and angiogenesis. Our findings provide a detailed resource for advancing our molecular understanding of stroke pathology and for discovering therapeutic targets in the repair phase of stroke recovery.

Meis1 Targets Protein Tyrosine Phosphatase Receptor J in Fibroblast to Retard Chronic Kidney Disease Progression.

Renal fibrosis is a common pathological feature of chronic kidney disease (CKD) with the proliferation and activation of myofibroblasts being definite effectors and drivers. Here, increased expression of Meis1 (myeloid ecotropic viral integration site 1) is observed, predominantly in the nucleus of the kidney of CKD patients and mice, and negatively correlates with serum creatinine. Fibroblast-specific knock-in of Meis1 inhibits myofibroblast activation and attenuates renal fibrosis and kidney dysfunction in CKD models. Overexpression of Meis1 in NRK-49F cells suppresses the pro-fibrotic response induced by transforming growth factor-β1 but accelerates by its knockdown. Mechanistically, Meis1 targets protein tyrosine phosphatase receptor J (Ptprj) to block renal fibrosis by inhibiting the proliferation and activation of fibroblasts. Finally, a new activator of Ptprj is identified through computer-aided virtual screening, which has the effect of alleviating renal fibrosis. Collectively, these results illustrate that the Meis1/Ptprj axis has therapeutic potential for clinically treating CKD.

Novel PTPRQ variants associated with hearing loss in a Chinese family PTPRQ variants in Chinese hearing loss.

Hearing loss is one of the most prevalent congenital sensory disorders. Over 50% of congenital hearing loss cases are attributed to genetic factors. The PTPRQ gene encodes the protein tyrosine phosphatase receptor Q, which plays an important role in maintaining the structure and function of the stereocilia of hair cells. Variants in the PTPRQ gene have been implicated in hereditary sensorineural hearing loss. Utilizing next-generation sequencing technology, we identified novel compound heterozygous variants (c.977G>A:p.W326X and c.6742C>T:p.Q2248X) in the PTPRQ gene within a Chinese national lineage, marking the first association of these variants with hereditary sensorineural hearing loss. Our findings further emphasize the critical role of PTPRQ in auditory function and contribute to a more comprehensive understanding of PTPRQ-associated hearing loss mechanisms, aiding in clinical management and genetic counseling.

Aptamer-Based Enforced Phosphatase-Recruiting Chimeras Inhibit Receptor Tyrosine Kinase Signal Transduction.

Aberrant phosphorylation of receptor tyrosine kinases (RTKs) is usually involved in tumor initiation, progression, and metastasis. However, developing specific and efficient molecular tools to regulate RTK phosphorylation remains a considerable challenge. In this study, we reported novel aptamer-based chimeras to inhibit the phosphorylation of RTKs, such as c-Met and EGFR, by enforced recruitment of a protein tyrosine phosphatase receptor type F (PTPRF). Our studies revealed that aptamer-based chimeras displayed a generic and potent inhibitory effect on RTK phosphorylation induced by growth factor or auto-dimerization in different cell lines and modulated cell biological behaviors by recruiting PTPRF. Furthermore, based on angstrom accuracy of the DNA duplex, the maximum catalytic radius of PTPRF was determined as ∼25.84 nm, providing a basis for the development of phosphatase-recruiting strategies. Taken together, our study provides a generic methodology not only for selectively mediating RTK phosphorylation and cellular biological processes but also for developing novel therapeutic drugs.

MiR-29a-3p orchestrates key signaling pathways for enhanced migration of human mesenchymal stem cells

BackgroundThe homing of human mesenchymal stem cells (hMSCs) is crucial for their therapeutic efficacy and is characterized by the orchestrated regulation of multiple signaling modules. However, the principal upstream regulators that synchronize these signaling pathways and their mechanisms during cellular migration remain largely unexplored.MethodsmiR-29a-3p was exogenously expressed in either wild-type or DiGeorge syndrome critical region 8 (DGCR8) knockdown hMSCs. Multiple pathway components were analyzed using Western blotting, immunohistochemistry, and real-time quantitative PCR. hMSC migration was assessed both in vitro and in vivo through wound healing, Transwell, contraction, and in vivo migration assays. Extensive bioinformatic analyses using gene set enrichment analysis and Ingenuity pathway analysis identified enriched pathways, upstream regulators, and downstream targets.ResultsThe global depletion of microRNAs (miRNAs) due to DGCR8 gene silencing, a critical component of miRNA biogenesis, significantly impaired hMSC migration. The bioinformatics analysis identified miR-29a-3p as a pivotal upstream regulator. Its overexpression in DGCR8-knockdown hMSCs markedly improved their migration capabilities. Our data demonstrate that miR-29a-3p enhances cell migration by directly inhibiting two key phosphatases: protein tyrosine phosphatase receptor type kappa (PTPRK) and phosphatase and tensin homolog (PTEN). The ectopic expression of miR-29a-3p stabilized the polarization of the Golgi apparatus and actin cytoskeleton during wound healing. It also altered actomyosin contractility and cellular traction forces by changing the distribution and phosphorylation of myosin light chain 2. Additionally, it regulated focal adhesions by modulating the levels of PTPRK and paxillin. In immunocompromised mice, the migration of hMSCs overexpressing miR-29a-3p toward a chemoattractant significantly increased.ConclusionsOur findings identify miR-29a-3p as a key upstream regulator that governs hMSC migration. Specifically, it was found to modulate principal signaling pathways, including polarization, actin cytoskeleton, contractility, and adhesion, both in vitro and in vivo, thereby reinforcing migration regulatory circuits.

The receptor protein tyrosine phosphatase PTPRK promotes intestinal repair and catalysis-independent tumour suppression.

PTPRK is a receptor tyrosine phosphatase that is linked to the regulation of growth factor signalling and tumour suppression. It is stabilized at the plasma membrane by trans homophilic interactions upon cell-cell contact. PTPRK regulates cell-cell adhesion but is also reported to regulate numerous cancer-associated signalling pathways. However, the signalling mechanism of PTPRK remains to be determined. Here, we find that PTPRK regulates cell adhesion signalling, suppresses invasion and promotes collective, directed migration in colorectal cancer cells. In vivo, PTPRK supports recovery from inflammation-induced colitis. In addition, we confirm that PTPRK functions as a tumour suppressor in the mouse colon and in colorectal cancer xenografts. PTPRK regulates growth factor and adhesion signalling, and suppresses epithelial to mesenchymal transition (EMT). Contrary to the prevailing notion that PTPRK directly dephosphorylates EGFR, we find that PTPRK regulation of both EGFR and EMT is independent of its catalytic function. This suggests that additional adaptor and scaffold functions are important features of PTPRK signalling.

The PTPN22 as Master Regulation in Autoimmune Diseases and Its Susceptibility to Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a long-term autoimmune condition that causes joint inflammation, resulting in pain, tenderness, expansion, and even joint malformation. It mostly causes inflammation and thickening of the synovium, the membrane that lines the joints. Joint erosion, cartilage breakdown, and function loss are all possible outcomes of RA over time. Though it can affect any joint in the body, it usually affects the smaller joints in the hands and feet. A significant role can be played by genetic ability in the progress of rheumatoid arthritis. The review's subject, "PTPN22" (sometimes referred to as "LYP in humans or PEP in mice"), is the typical non receptor PTP belonging to the proline rich subgroup of Type I. PTPN22 is a "major negative regulator of T-cell receptor (TCR) signal transduction" which is mostly express in the immune cells. Interestingly, a mutation in this gene has been related to the onset of many autoimmune disorders. Several genetic variants have been identified that contribute to the risk of developing RA, including rs2476601. This review discussed the PTPN22 as master regulation of immune system and the role of rs2476601 in RA.

Next‐generation sequencing identifies that protein tyrosine phosphatase receptor type D mutation is favorable to immunotherapy in human cancer

AbstractProtein tyrosine phosphatase receptors (PTPRs) play a crucial part in numerous tumor processes. However, the effect of PTPR mutations on the immune checkpoint inhibitor (ICI) response needs to be further clarified. Next‐generation sequencing was performed on 453 cancer patients in our internal cohort. The genomic alterations, tumor mutation burden (TMB), neoantigens, and immune‐related features/pathways of other cohorts were analyzed. Here, protein tyrosine phosphatase receptor type D (PTPRD) has a high mutation frequency and an intensified co‐occurrence with other PTPRs. Patients who responded to ICI therapy were enriched with the PTPRD mutation (PTPRD‐MUT). PTPRD‐MUT patients had a higher objective response rate (44.1% vs. 29.1%), TMB/neoantigens, and longer overall survival time than PTPRD‐wild‐type (PTPRD‐WT) patients. Genomic alterations with a higher mutation frequency of genes (such as LRP1B) were enriched in PTPRD‐MUT patients. More abundant immune cells (including CD8+ T cells and macrophages) and upregulated immune‐related genes were found in PTPRD‐MUT patients. Moreover, Gene sets enrichment analyses showed that multiple antitumor immune pathways are activated in PTPRD‐MUT patients. Therefore, PTPRD‐MUT is beneficial for immunotherapy of multiple cancer types and may be a predictive biomarker of patient clinical outcomes.

Protein Tyrosine Phosphatase Receptors N and N2 Control Pituitary Melanotroph Development and POMC Expression.

The neuroendocrine marker genes Ptprn and Ptprn2 encode protein tyrosine phosphatase receptors N and N2, 2 members of protein tyrosine phosphatase receptors void of enzymatic activity, and whose function and mechanism of action have not been elucidated. To explore the role(s) of Ptprn and Ptprn2 on the hypothalamic-pituitary-adrenal axis, we used mice in which both genes were knocked out (DKO). The focus in this study was on corticotrophs and melanotrophs from the anterior and intermediate lobes of the pituitary gland, respectively. In both sexes, DKO caused an increase in the expression of the corticotroph/melanotroph genes Pomc and Tbx19 and the melanotroph-specific gene Pax7. We also found in vivo and in vitro increased synthesis and release of beta-endorphin, alpha-melanocyte-stimulating hormone, and ACTH in DKO mice, which was associated with increased serum corticosterone levels and adrenal mass. DKO also increased the expression of other melanotroph-specific genes, but not corticotroph-specific genes. The dopaminergic pathway in the hypothalamus and dopaminergic receptors in melanotrophs were not affected in DKO mice. However, hyperplasia of the intermediate lobe was observed in DKO females and males, accompanied by increased proopiomelanocortin immunoreactivity per cell. These results indicate that protein tyrosine phosphatase receptor type N contributes to hypothalamic-pituitary-adrenal function by being involved in processes governing postnatal melanotroph development and Pomc expression.