A multifunctional docking site mediates signaling and transformation by the hepatocyte growth factor/scatter factor receptor family

Signaling by tyrosine kinase receptors is mediated by selective interactions between individual Src homology 2 (SH2) domains of cytoplasmic effectors and specific phosphotyrosine residues in the activated receptor. Here, we report the existence in the hepatocyte growth factor/scatter factor (HGF/SF) receptor of a multifunctional docking site made of the tandemly arranged degenerate sequence YVH/NV. Phosphorylation of this site mediates intermediate- to high-affinity interactions with multiple SH2-containing signal transducers, including phosphatidylinositol 3-kinase, phospholipase C gamma, pp60c-src, and the GRB-2-Sos complex. Mutation of the two tyrosines results in loss of biological function, as shown by abrogation of the transforming activity in the oncogenic counterpart of the receptor. The same bidentate motif is conserved in the evolutionarily related receptors Sea and Ron, suggesting that in all members of the HGF/SF receptor family, signal transduction is channeled through a multifunctional binding site.

Transfer of motogenic and invasive response to scatter factor/hepatocyte growth factor by transfection of human MET protooncogene

The MET protooncogene encodes p190MET, a tyrosine kinase which is the receptor for a molecule known as scatter factor or hepatocyte growth factor (SF/HGF). This molecule has different biological activities, including stimulation of cell motility, promotion of matrix invasion and, in some cells, mitogenesis. We have cloned the full-length MET cDNA and transfected it into NIH 3T3 fibroblasts. Stable transfectants expressed the p190MET receptor together with two previously described truncated forms of 140 and 130 kDa lacking the tyrosine kinase domain. All three forms bound radiolabeled SF/HGF. The factor stimulated tyrosine kinase activity of the transfected p190MET and induced changes in cell shape, migration in Boyden chambers, and invasion of collagen matrices in vitro. The motile and invasive phenotype was transient and strictly dependent on the presence of SF/HGF. The factor did not stimulate either cell growth or thymidine incorporation in transfected cells, while it promoted colony formation in soft agar in the presence of 5% fetal calf serum. These data show that, in the presence of its ligand, the MET receptor expressed in fibroblasts induces cells to pursue a motogenic-invasive rather than a proliferative program.

Specific uncoupling of GRB2 from the Met receptor. Differential effects on transformation and motility

The biological effects of hepatocyte growth factor/scatter factor are mediated by autophosphorylation of its receptor, the Met tyrosine kinase, on two carboxyl-terminal tyrosines. These phosphotyrosines (Y1349VHVNATY1356VNV) are multifunctional docking sites for several effectors. Grb2, the adaptor for the Ras guanyl-nucleotide exchanger SOS, binds to Tyr1356 in the YVNV motif. By site-directed mutagenesis we either abrogated or duplicated the Grb2 consensus, without interfering with the other effectors. Loss of the link with Grb2 severely impaired transformation. The same mutation, however, had no effect on the "scattering" response, indicating that the level of signal which can be reached by Grb2-independent routes is permissive for motility. Duplication of the Grb2 binding site enhanced transformation and left motility unchanged. Thus, two Met-mediated biological responses, motility and growth, can be dissociated on the basis of their differential requirement for a direct link with Ras.

Interaction of thymic stromal lymphopoietin, IL-33, and their receptors in epithelial cells in eosinophilic chronic rhinosinusitis with nasal polyps

BACKGROUND

Thymic stromal lymphopoietin (TSLP), IL-25, and IL-33 system contribute to the initiation and development of Th2 responses. This study aimed to explore the involvement of TSLP, IL-25, IL-33, and their receptors in type 2 T-helper (Th) responses in chronic rhinosinusitis with nasal polyps (CRSwNPs) and their cross-regulation in human nasal epithelial cells (HNECs).

METHODS

Immunohistochemistry, quantitative RT-PCR, ELISA, Bio-Plex assay, and flow cytometry were used to detect the expression of TSLP/common γ-like TSLP receptor (TSLPR)/IL-7 receptor α (IL-7Rα), IL-25/IL-17B receptor (IL-17RB), and IL-33/membrane-bound ST2 (ST2L)/soluble ST2 (sST2) in sinonasal mucosa and HNECs. HNECs cultured at an air-liquid interface were used to explore the expression in regulation of these cytokine systems.

RESULTS

Compared with controls and noneosinophilic CRSwNP, the expression of TSLP/TSLPR/IL-7Rα and ST2L/sST2 was significantly increased in eosinophilic CRSwNP, predominantly in epithelial cells. In contrast, the expression of IL-33 and IL-25/IL-17RB was enhanced in epithelial cells in both eosinophilic and noneosinophilic CRSwNP compared to controls. The expression of TSLP, TSLPR, and ST2L was positively correlated with symptom and computer tomography scan scores in eosinophilic CRSwNP and with Th2 cytokine expression in sinonasal mucosa. The expression of ST2L was correlated with TSLP and its receptor expression. TSLP could induce ST2L expression that promoted IL-33-induced TSLP expression in HNECs. In addition, TSLP/TSLPR/IL-7Rα and ST2L could be induced by Th2 cytokines, while IL-25/IL-17RB and IL-33 could be upregulated by Th1/Th17 cytokines, in HNECs.

CONCLUSIONS

The positive feedback loop between TSLP, IL-33 and their receptors, and Th2 cytokines may facilitate Th2-skewed inflammation in eosinophilic CRSwNP.

A point mutation in the MET oncogene abrogates metastasis without affecting transformation

The MET oncogene encodes the tyrosine kinase receptor for hepatocyte growth factor/scatter factor (HGF), known to stimulate invasive growth of epithelial cells. MET is overexpressed in a significant percentage of human cancers and is amplified during the transition between primary tumors and metastasis. To investigate whether this oncogene is directly responsible for the acquisition of the metastatic phenotype, we exploited a single-hit oncogenic version of MET, able to transform and to confer invasive and metastatic properties to nontumorigenic cells, both in vitro and in nude mice. We mutagenized the signal transducer docking site of Met (Y1349VHVX3Y1356VNV), which has the uncommon property of binding and activating multiple src homology region 2 (SH2)-containing intracellular effectors. Notably, a point mutation (H1351 --> N) increased the transforming ability of the oncogene but abolished its metastatic potential. This mutation duplicates the Grb2 binding site, super-activating the Ras pathway and preventing the binding of the other intracellular transducers. Complementation in trans with another nonmetastatic mutant (N1358 --> H), recruiting all the transducers downstream to Met except Grb2, rescued the invasive-metastatic phenotype. It is concluded that the metastatic potential of the MET oncogene relies on the properties of its multifunctional docking site, and that a single point mutation affecting signal transduction can dissociate neoplastic transformation from metastasis.

The safety and effectiveness of TM81, a Chinese herbal medicine, in the treatment of type 2 diabetes: a randomized double-blind placebo-controlled trial

AIM

TM81 (or Tang-Min-Ling-Wan) is a Chinese medicine. Previous studies suggested that this medicine is effective for treating type 2 diabetes. This controlled trial evaluated the safety and effectiveness of TM81 in the treatment of type 2 diabetic patients.

METHODS

This study was a large-scale controlled clinical trial to evaluate the safety and effectiveness of TM81 on type 2 diabetes. After a 2-week run-in period, 480 overweight type 2 early-stage diabetic patients [35-65 years old, HbA1c ≥ 7.0%, fasting plasma glucose (FPG) 7.0-13.9 mM or 2 h plasma glucose (PG) > 11.1 mM, body mass index (BMI) ≥ 24 kg/m(2)] were enrolled. These patients were divided into a TM81 group and placebo group in a 3 : 1 ratio. The subjects received 6 g TM81 or placebo, three times daily for 12 weeks.

RESULTS

After treatment, the HbA1c decrease was 1.02% in the TM81 group versus 0.47% in the placebo group. The FPG decreased 0.8 ± 0.1 mM in the TM81 group versus an increase of 0.2 ± 0.2 mM in the placebo group. The PG decreased 2.7 ± 0.3 mM in the TM81 group versus a decrease of 0.9 ± 0.4 mM in the placebo group (all p < 0.05). The TM81 was more effective for patients with higher baseline HbA1c levels. The TM81 group also showed improved β-cell function and increased homeostatic model assessment (HOMA)-β. In addition, body weight, BMI and waist circumference of subjects in the TM81 group were reduced, and the symptoms related to diabetes were improved. There were no significant differences in the types and frequency of adverse reactions between the two groups.

CONCLUSIONS

The data showed that TM81 is effective in controlling blood glucose level and is safe to use in patients with early-stage type 2 diabetes.

The effects of hyperuricaemia on flow-mediated and nitroglycerin-mediated dilatation in high-risk patients

BACKGROUND AND AIMS

Uric acid is emerging as one of the newer risk markers to consider in the cardiovascular risk assessment because it is demonstrated to be associated with adverse cardiovascular outcomes, particularly in high cardiovascular risk patients. One of the proposed mechanisms involving hyperuricaemia is the development of vascular damage. The aim of this study is to examine the role of hyperuricaemia on vascular function in patients with high cardiovascular risk.

METHODS AND RESULTS

We examined the clinical significance of hyperuricaemia in relation to vasomotor response of the brachial artery by using high-resolution ultrasound in 304 subjects with coronary artery disease and/or diabetes. Nitroglycerin-mediated dilatation (NMD) was significantly lower in the hyperuricaemic group compared with the normouricaemic group (12.8 ± 6.9% vs. 16.2 ± 7.7%, p < 0.001), but no significant difference was observed in flow-mediated dilatation (FMD) between the two groups [3.78 (95% CR: 1.5-9.9) vs. 3.88 (95% CR: -2.6 to 9.9), p = 0.78]. Multivariate analysis demonstrated that smoking was the strongest predictor of FMD (b = -0.81, p = 0.02); and that smoking (b = -2.62, p = 0.003), SBP (b = -0.11, p = 0.001), hyperuricaemia (b = -2.11, p = 0.02) and use of nitrates (b = -3.30, p = 0.001) were independent predictors of NMD.

CONCLUSION

High cardiovascular risk patients with hyperuricaemia had a lower NMD than those with normouricaemia. Importantly, hyperuricaemia was independently associated with NMD after multivariable adjustments. To further understand the pathophysiological mechanisms involving hyperuricaemia, particularly in the context of impaired NMD, further experimental and clinical studies are needed.

Effect of Early Swimming on the Behavior and Striatal Transcriptome of the Shank3 Knockout Rat Model of Autism

BACKGROUND

Autism spectrum disorder (ASD) is a developmental disorder characterized by social behavior deficits and stereotyped behaviors in childhood that lacks satisfactory medical intervention. Early swimming intervention is a noninvasive method combining enriched environment and exercise, which has been proven to improve brain development in young children and to treat neurodevelopmental diseases.

METHODS

In this study, we tested the autism-like behavior of rats with deletions in exons 11-21 of the Shank3 gene and evaluated the effect of early swimming intervention (from postnatal day 8 to 60) on the behavior of this animal model of autism. In addition, the transcriptomes of the striatal tissues of wild-type, Shank3 knockout and Shank3 knockout swimming groups rats were analyzed.

RESULTS

Shank3 knockout rats exhibit core symptoms of autism, and early swimming improved the social and stereotyped behaviors in this autism rat model. Transcriptomics results revealed that compared to the wild-type group, 291 differentially expressed genes (DEGs) were identified in the striatum of the Shank3 knockout group. Compared to Shank3 knockout group, 534 DEGs were identified in the striatum of Shank3 knockout swimming group. The DEGs annotated by Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway shows that the impacts of Shank3 deletion were primarily reflected in synaptic structure, development, morphology, receptor function and signaling, and swimming primarily changed the terms related to the synapses in the striatum of Shank3 knockout rats, including the morphology, structure, composition, development and regulation of synapses.

CONCLUSION

Early swimming intervention can ameliorate behavioral abnormalities caused by Shank3 knockout, by a mechanism that may involve the process of striatal synaptic development and should be further investigated.

[Clinical effect and safety of pegylated interferon-α-2b injection (Y shape, 40 kD) in treatment of HBeAg-positive chronic hepatitis B patients]

Objective: To investigate the clinical effect and safety of long-acting pegylated interferon-α-2b (Peg-IFN-α-2b) (Y shape, 40 kD) injection (180 μg/week) in the treatment of HBeAg-positive chronic hepatitis B (CHB) patients, with standard-dose Peg-IFN-α-2a as positive control. Methods: This study was a multicenter, randomized, open-label, and positive-controlled phase III clinical trial. Eligible HBeAg-positive CHB patients were screened out and randomized to Peg-IFN-α-2b (Y shape, 40 kD) trial group and Peg-IFN-α-2a control group at a ratio of 2:1. The course of treatment was 48 weeks and the patients were followed up for 24 weeks after drug withdrawal. Plasma samples were collected at screening, baseline, and 12, 24, 36, 48, 60, and 72 weeks for centralized detection. COBAS® Ampliprep/COBAS® TaqMan® HBV Test was used to measure HBV DNA level by quantitative real-time PCR. Electrochemiluminescence immunoassay with Elecsys kit was used to measure HBV markers (HBsAg, anti-HBs, HBeAg, anti-HBe). Adverse events were recorded in detail. The primary outcome measure was HBeAg seroconversion rate after the 24-week follow-up, and non-inferiority was also tested. The difference in HBeAg seroconversion rate after treatment between the trial group and the control group and two-sided confidence interval (CI) were calculated, and non-inferiority was demonstrated if the lower limit of 95% CI was > -10%. The t-test, chi-square test, or rank sum test was used according to the types and features of data. Results: A total of 855 HBeAg-positive CHB patients were enrolled and 820 of them received treatment (538 in the trial group and 282 in the control group). The data of the full analysis set showed that HBeAg seroconversion rate at week 72 was 27.32% in the trial group and 22.70% in the control group with a rate difference of 4.63% (95% CI -1.54% to 10.80%, P = 0.1493). The data of the per-protocol set showed that HBeAg seroconversion rate at week 72 was 30.75% in the trial group and 27.14% in the control group with a rate difference of 3.61% (95% CI -3.87% to 11.09%, P = 0.3436). 95% CI met the non-inferiority criteria, and the trial group was non-inferior to the control group. The two groups had similar incidence rates of adverse events, serious adverse events, and common adverse events. Conclusion: In Peg-IFN-α regimen for HBeAg-positive CHB patients, the new drug Peg-IFN-α-2b (Y shape, 40 kD) has comparable effect and safety to the control drug Peg-IFN-α-2a.

MiR-524 inhibits cell proliferation and induces cell apoptosis in thyroid cancer via targeting SPAG9

OBJECTIVE

To investigate the effect of miR-524 on the proliferation of thyroid cancer and its underlying mechanism.

PATIENTS AND METHODS

MiR-524 expression levels in thyroid cancer samples and para-cancer tissues were tested by quantitative Real-time polymerase chain reaction (qRT-PCR). Cells proliferative ability and apoptosis were evaluated through methyl thiazolyl tetrazolium (MTT) and apoptosis assays, respectively. Luciferase reporter assay was used to confirm the regulatory mechanism.

RESULTS

MiR-524 expression was reduced in thyroid cancer specimen (p<0.05). Up-regulated miR-524 expression inhibited the proliferative ability and enhanced cell apoptosis of thyroid cancer cells. SPAG9 was a target gene of miR-524, and was reversely regulated by miR-524.

CONCLUSIONS

MiR-524 represses thyroid cancer cell proliferation and induces cell apoptosis via targeting SPAG9.

Exercise changes gut microbiota - a new idea to explain that exercise improves autism

The effect of exercise interventions on autism spectrum disorder (ASD) has been demonstrated in many studies. Then, the discovery of a bidirectional relationship between the gut microbiome (GM) and the central nervous system (CNS) led to the concept of the microbial gut-brain axis (MGBA) and linked the abnormal GM to a variety of neuropsychiatric disorders, autism being one of them. Research on improving the GM through exercise is also starting to come into focus. However, there are currently few studies on exercise intervention in the GM of autism. The purpose of this review was to find evidence to explore the possible potential effects of exercise to improve the behavior of individuals with autism in the MGBA in this treatment, as well as the potential of GM as an exercise treatment for autism. We will explore (1) changes in GM components of ASD and their relationship to the pathophysiology of ASD; (2) the relationship between exercise and changes in GM components (3) the effect of exercise on GM in CNS disorders. Ultimately, we conclude to find that Streptococcus, Bifidobacterium, Clostridium, Bacteroides, and Blautia may be potential effectors through the MGBA network during exercise to ameliorate ASD targeting microbiotas. They deserve high attention in the follow-up studies.

Changes in the urinary proteome in rats with regular swimming exercise

Purpose

Urine can sensitively reflect early pathophysiological changes in the body. The purpose of this study was to explore the changes of urine proteome in rats with regular swimming exercise.

Methods

In this study, experimental rats were subjected to daily moderate-intensity swimming exercise for 7 weeks. Urine samples were collected at weeks 2, 5, and 7 and were analyzed by using liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS).

Results

Unsupervised clustering analysis of all urinary proteins identified at week 2 showed that the swimming group was distinctively different from the control group. Compared to the control group, a total of 112, 61 and 44 differential proteins were identified in the swimming group at weeks 2, 5 and 7, respectively. Randomized grouping statistical analysis showed that more than 85% of the differential proteins identified in this study were caused by swimming exercise rather than random allocation. According to the Human Protein Atlas, the differential proteins that have human orthologs were strongly expressed in the liver, kidney and intestine. Functional annotation analysis revealed that these differential proteins were involved in glucose metabolism and immunity-related pathways.

Conclusion

Our results revealed that the urinary proteome could reflect significant changes after regular swimming exercise. These findings may provide an approach to monitor the effects of exercise of the body.

[Analysis of four children with anomalous origin of the left coronary artery from the right sinus with interarterial course]

Objective: To investigate the clinical features and improve the diagnosis and treatment of anomalous origin of the left coronary artery from the right coronary sinus with an interarterial course (ALCA-R-IAC) between the ascending aorta and main pulmonary artery in children. Methods: A retrospective analysis of the clinical manifestation, laboratory test, radiological feature, treatment and prognosis were conducted in four female children presented with ALCA-R-IAC in Beijing Children's Hospital from November 2015 to June 2018. Results: The four girls with onset age of 7.5-14.7 years were diagnosed with ALCA-R-IAC by CT coronary angiography (CTCA). Four children presented with exercise-induced syncope and clinical manifestations of acute myocardial infarction including 3 patients with acute left heart failure, 1 cardiogenic shock and 1 cardiac arrest. Nervous system involvement was found in one patient. Troponin I increased significantly to 20.65-50.00 μg/L in the four patients. Electrocardiogram (ECG) developed signs of left main coronary artery involvement. Echocardiography revealed reduced left ventricular ejection fraction (LVEF) of 25%-45% in three children and suspected anomalous origin of the left coronary artery in one child. CTCA showed an anomalous left coronary artery originating from the right coronary sinus, which had an interarterial course between the aorta and pulmonary artery leading to a slim left main coronary trunk. Two children underwent unroofing procedure and the other two children in whom physical activities were restricted received conservative managements. During a regular follow-up period of 12-43 months, all the children survived without recurrent symptoms and had good prognosis. Conclusions: ALCA-R-IAC can present as exercise-related syncope and acute myocardial infarction, even sudden death in children and adolescents. CTCA is helpful to clarify the early diagnosis of ALCA-R-IAC. Surgical intervention is the main treatment for ALCA-R-IAC and strenuous physical activities should be avoided.

Structural and functional domains critical for constitutive activation of the HGF-receptor (Met)

The MET gene, encoding the tyrosine kinase receptor for Hepatocyte Growth Factor, is a potentially harmful oncogene overexpressed in a significant fraction of human cancers. To study the molecular mechanisms responsible for oncogenic activation, the biochemical and biological properties of a number of MET constructs were analysed. The native heterodimeric receptor (alpha beta), the beta chain alone, as well as a kinase defective mutant did not transform rodent fibroblasts upon transfection. The cytoplasmic domain, truncated immediately below the transmembrane region, acquired constitutive tyrosine kinase activity in vivo, produced foci of transformation, and was tumorigenic in nude mice. Removal of the first 39 amino acids of the juxtamembrane domain resulted in loss of constitutive activation in vivo and transforming potential, without impairment of the in vitro kinase activity. Replacement of the juxtamembrane domain with 5' TPR sequences restored constitutive kinase activation and transforming properties. Site-directed mutagenesis of either of the two tyrosine residues involved in the positive regulation of the catalytic activity upon phosphorylation (Y1234 or Y1235 in the kinase domain of the HGF receptor), strongly impaired TRP-MET transforming potential. These data show that: (1) the truncated cytoplasmic HGF receptor has constitutive kinase activity and is oncogenic; (2) the first 39 amino acids of the juxtamembrane domain and (3) the regulatory tyrosines in the catalytic domain are required to unleash its transforming potential.

MiR-524 inhibits cell proliferation and induces cell apoptosis in thyroid cancer via targeting SPAG9

The article "MiR-524 inhibits cell proliferation and induces cell apoptosis in thyroid cancer via targeting SPAG9", by Z. Zhen, F. Dong, H. Shen, Q.-G. Wang, L. Yang, J. Hu, published in Eur Rev Med Pharmacol Sci 2018; 22 (12): 3812-3818-DOI: 10.26355/eurrev_201806_15265-PMID: 29949157, has been retracted by the authors due to some unrepeated data in their current research. The Publisher apologizes for any inconvenience this may cause. https://www.europeanreview.org/article/15265.

[Analysis of suspected occupational diseases cases and subsequent diagnosis follow-up investigation in Hubei Province from 2020 to 2021]

Objective: To understand the epidemiological characteristics of suspected occupational diseases cases, and to track the subsequent diagnosis of suspected cases in Hubei Province from 2020 to 2021, and to provide theoretical basis for the supervision of suspected occupational diseases. Methods: In April 2022, the data of suspected occupational diseases cases and occupational diseases in Hubei Province from 2020 to 2021 were collected by the Occupational Diseases and Health Risk Factors Information Surveillance System. The distribution and diagnosis of suspected occupational diseases cases were analyzed. We investigated undiagnosed suspected occupational diseases by telephone. Results: From 2020 to 2021, a total of 1872 cases of suspected occupational diseases in 6 categories and 18 species were reported in Hubei Province. The top three suspected occupational diseases were suspected occupational noise deafness (36.75%, 688/1872), suspected coal worker's pneumoconiosis (33.07%, 619/1872) and suspected silicosis (20.99%, 393/1872). The diagnosis rate of suspected occupational diseases was 33.60% (629/1872). The rate of confirmed diagnosis was 63.59% (400/629). The diagnosis rate (26.86%, 456/1698) and rate of confirmed diagnosis (55.48%, 253/456) of suspected occupational diseases detected by occupational health examination were the lowest. The diagnosis rate of suspected occupational diseases detected by comprehensive medical institutions and private medical institutions were lower than disease prevention and control institutions and occupational disease prevention center (P<0.05). The main reasons for not entering the diagnostic procedure included that workers were not informed that they were diagnosed as suspected occupational diseases (31.55%, 124/393), workers were unwilling to apply for occupational disease diagnosis (18.56%, 73/393), and some workers planned to apply for diagnosis but had not yet applied (10.69%, 42/393) . Conclusion: Occupational noise deafness, coal worker's pneumoconiosis and silicosis are the main diseases of suspected occupational diseases in Hubei Province. In order to increase the diagnosis rate and confirmed diagnosis rate of suspected occupational diseases, it is suggested to strengthen management and supervision from the aspects of case management, information warning and worker notification.

The motogenic and mitogenic responses to HGF are amplified by the Shc adaptor protein

The receptor of Hepatocyte Growth Factor-Scatter Factor (HGF) is a tyrosine kinase which regulates cell motility and growth. After ligand-induced tyrosine phosphorylation, the HGF receptor associates with the Shc adaptor, via the SH2 domain. Site-directed mutagenesis of the HGF receptor indicates that phosphotyrosines Y1349VHV and Y1356VNV can work as docking sites for Shc. The Kd of this interaction, measured in real time using synthetic phosphopeptides and recombinant Shc on a BIAcore biosensor, is 150 nm for both sites. After stimulation of the HGF receptor, Shc is phosphorylated on Y317VNV, generating an high affinity binding site for Grb2 (Kd = 15 nM). This duplicates the high affinity binding site for Grb2 present on the HGF receptor (Y1356VNV). Thus HGF stimulation can trigger the Ras pathway by recruiting Grb2 both directly through the receptor, and indirectly, through Shc. Overexpression of wild-type Shc, but not of the Y317-->F mutant, enhances cell migration and growth in response to HGF. These data show that Shc is a relevant substrate of the HGF receptor, and works as an 'amplifier' of the motogenic as well as of the mitogenic response.