Smoking-induced CCNA2 expression promotes lung adenocarcinoma tumorigenesis by boosting AT2/AT2-like cell differentiation.

Lung adenocarcinoma (LUAD), a type of non-small cell lung cancer (NSCLC), originates from not only bronchial epithelial cells but also alveolar type 2 (AT2) cells, which could differentiate into AT2-like cells. AT2-like cells function as cancer stem cells (CSCs) of LUAD tumorigenesis to give rise to adenocarcinoma. However, the mechanism underlying AT2 cell differentiation into AT2-like cells in LUAD remains unknown. We analyze genes differentially expressed and genes with significantly different survival curves in LUAD, and the combination of these two analyses yields 147 differential genes, in which 14 differentially expressed genes were enriched in cell cycle pathway. We next analyze the protein levels of these genes in LUAD and find that Cyclin-A2 (CCNA2) is closely associated with LUAD tumorigenesis. Unexpectedly, high CCNA2 expression in LUAD is restrictedly associated with smoking and independent of other driver mutations. Single-cell sequencing analyses reveal that CCNA2 is predominantly involved in AT2-like cell differentiation, while inhibition of CCNA2 significantly reverses smoking-induced AT2-like cell differentiation. Mechanistically, CCNA2 binding to CDK2 phosphorylates the AXIN1 complex, which in turn induces ubiquitination-dependent degradation of ß-catenin and inhibits the WNT signaling pathway, thereby failing AT2 cell maintenance. These results uncover smoking-induced CCNA2 overexpression and subsequent WNT/ß-catenin signaling inactivation as a hitherto uncharacterized mechanism controlling AT2 cell differentiation and LUAD tumorigenesis.

Phosphorylation of human glioma-associated oncogene 1 on Ser937 regulates Sonic Hedgehog signaling in medulloblastoma.

Aberrant activation of sonic hedgehog (SHH) signaling and its effector transcriptional factor GLI1 are essential for oncogenesis of SHH-dependent medulloblastoma (MBSHH) and basal cell carcinoma (BCC). Here, we show that SHH inactivates p38α (MAPK14) in a smoothened-dependent manner, conversely, p38α directly phosphorylates GLI1 on Ser937/Ser941 (human/mouse) to induce GLI1's proteasomal degradation and negates the transcription of SHH signaling. As a result, Gli1S941E loss-of-function knock-in significantly reduces the incidence and severity of smoothened-M2 transgene-induced spontaneous MBSHH, whereas Gli1S941A gain-of-function knock-in phenocopies Gli1 transgene in causing BCC-like proliferation in skin. Correspondingly, phospho-Ser937-GLI1, a destabilized form of GLI1, positively correlates to the overall survival rate of children with MBSHH. Together, these findings indicate that SHH-induced p38α inactivation and subsequent GLI1 dephosphorylation and stabilization in controlling SHH signaling and may provide avenues for future interventions of MBSHH and BCC.

Clinical value of precise rehabilitation nursing in management of cerebral infarction.

BACKGROUND: Cerebral infarction, previously referred to as cerebral infarction or ischemic stroke, refers to the localized brain tissue experiencing ischemic necrosis or softening due to disorders in brain blood supply, ischemia, and hypoxia. The precision rehabilitation nursing model for chronic disease management is a continuous, fixed, orderly, and efficient nursing model aimed at standardizing the clinical nursing process, reducing the wastage of medical resources, and improving the quality of medical services. AIM: To analyze the value of a precise rehabilitation nursing model for chronic disease management in patients with cerebral infarction. METHODS: Patients (n = 124) admitted to our hospital with cerebral infarction between November 2019 and November 2021 were enrolled as the study subjects. The random number table method was used to divide them into a conventional nursing intervention group (n = 61) and a model nursing intervention group (n = 63). Changes in the nursing index for the two groups were compared after conventional nursing intervention and precise rehabilitation intervention nursing for chronic disease management. RESULTS: Compared with the conventional intervention group, the model intervention group had a shorter time to clinical symptom relief (P < 0.05), lower Hamilton Anxiety Scale and Hamilton Depression Scale scores, a lower incidence of total complications (P < 0.05), a higher disease knowledge mastery rate, higher safety and quality, and a higher overall nursing satisfaction rate (P < 0.05). CONCLUSION: The precision rehabilitation nursing model for chronic disease management improves the clinical symptoms of patients with cerebral infarction, reducing the incidence of total complications and improving the clinical outcome of patients, and is worthy of application in clinical practice.

Smurf1 polyubiquitinates on K285/K282 of the kinases Mst1/2 to attenuate their tumor-suppressor functions.

Sterile 20-like kinases Mst1 and Mst2 (Mst1/2) and large tumor suppressor 1/2 are core kinases to mediate Hippo signaling in maintaining tissue homeostasis. We have previously demonstrated that Smad ubiquitin (Ub) regulatory factor 1 (Smurf1), a HECT-type E3 ligase, ubiquitinates and in turn destabilizes large tumor suppressor 1/2 to induce the transcriptional output of Hippo signaling. Here, we unexpectedly find that Smurf1 interacts with and polyubiquitinates Mst1/2 by virtue of K27- and K29-linked Ub chains, resulting in the proteasomal degradation of Mst1/2 and attenuation of their tumor-suppressor functions. Among the potential Ub acceptor sites on Mst1/2, K285/K282 are conserved and essential for Smurf1-induced polyubiquitination and degradation of Mst1/2 as well as transcriptional output of Hippo signaling. As a result, K285R/K282R mutation of Mst1/2 not only negates the transcriptional output of Hippo signaling but enhances the tumor-suppressor functions of Mst1/2. Together, we demonstrate that Smurf1-mediated polyubiquitination on K285/K282 of Mst1/2 destabilizes Mst1/2 to attenuate their tumor-suppressor functions. Thus, the present study identifies Smurf1-mediated ubiquitination of Mst1/2 as a hitherto uncharacterized mechanism fine-tuning the Hippo signaling pathway and may provide additional targets for therapeutic intervention of diseases associated with this important pathway.

SUMOylation of Rho-associated protein kinase 2 induces goblet cell metaplasia in allergic airways.

Allergic asthma is characterized by goblet cell metaplasia and subsequent mucus hypersecretion that contribute to the morbidity and mortality of this disease. Here, we explore the potential role and underlying mechanism of protein SUMOylation-mediated goblet cell metaplasia. The components of SUMOylaion machinery are specifically expressed in healthy human bronchial epithelia and robustly upregulated in bronchial epithelia of patients or mouse models with allergic asthma. Intratracheal suppression of SUMOylation by 2-D08 robustly attenuates not only allergen-induced airway inflammation, goblet cell metaplasia, and hyperreactivity, but IL-13-induced goblet cell metaplasia. Phosphoproteomics and biochemical analyses reveal SUMOylation on K1007 activates ROCK2, a master regulator of goblet cell metaplasia, by facilitating its binding to and activation by RhoA, and an E3 ligase PIAS1 is responsible for SUMOylation on K1007. As a result, knockdown of PIAS1 in bronchial epithelia inactivates ROCK2 to attenuate IL-13-induced goblet cell metaplasia, and bronchial epithelial knock-in of ROCK2(K1007R) consistently inactivates ROCK2 to alleviate not only allergen-induced airway inflammation, goblet cell metaplasia, and hyperreactivity, but IL-13-induced goblet cell metaplasia. Together, SUMOylation-mediated ROCK2 activation is an integral component of Rho/ROCK signaling in regulating the pathological conditions of asthma and thus SUMOylation is an additional target for the therapeutic intervention of this disease.

Sonic hedgehog signaling: Alternative splicing and pathogenic role in medulloblastoma.

Alternative splicing (AS) produces the different mRNA splicing bodies, which are then translated into multiple protein isoforms and participate in various biological functions. With a deeper understanding of alternative splicing through the study of transcriptomes using high-throughput sequencing-based methods, the correlation between aberrant AS and diseases triggered a great concern, especially abnormal AS and cancer. Medulloblastoma (MB) is an intracranial tumor in children. Sonic hedgehog MB (SHH-MB) accounted for approximately 30% of MB, which is associated with the activation of SHH signaling. Growing evidence shows that aberrant AS is closely related to the tumorigenesis of MB. Here, we briefly introduced the AS and its mechanism. Next, we described canonical/noncanonical hedgehog signaling and its correlation with MB. The main description focused on AS of various regulators in canonical hedgehog signaling in MB. In addition, we also described AS of various regulators in noncanonical hedgehog signaling. Meanwhile, activated hedgehog signaling also induces AS in MB. Then, we pointed out that aberrant AS of hedgehog signaling is associated with different MB subgroups. Finally, we summarized the therapeutic applications of targeted AS in cancer treatment. In summary, further understanding of AS in SHH-MB could develop therapeutic targets for splicing factors which may be a novel therapeutic strategy.

Control of mitochondria-associated endoplasmic reticulum membranes by protein S-palmitoylation: Novel therapeutic targets for neurodegenerative diseases.

Mitochondria-associated endoplasmic reticulum membranes (MAMs) are dynamic coupling structures between mitochondria and the endoplasmic reticulum (ER). As a new subcellular structure, MAMs combine the two critical organelle functions. Mitochondria and the ER could regulate each other via MAMs. MAMs are involved in calcium (Ca2+) homeostasis, autophagy, ER stress, lipid metabolism, etc. Researchers have found that MAMs are closely related to metabolic syndrome and neurodegenerative diseases (NDs). The formation of MAMs and their functions depend on specific proteins. Numerous protein enrichments, such as the IP3R-Grp75-VDAC complex, constitute MAMs. The changes in these proteins govern the interaction between mitochondria and the ER; they also affect the biological functions of MAMs. S-palmitoylation is a reversible protein post-translational modification (PTM) that mainly occurs on protein cysteine residues. More and more studies have shown that the S-palmitoylation of proteins is closely related to their membrane localization. Here, we first briefly describe the composition and function of MAMs, reviewing the component and biological roles of MAMs mediated by S-palmitoylation, elaborating on S-palmitoylated proteins in Ca2+ flux, lipid rafts, and so on. We try to provide new insight into the molecular basis of MAMs-related diseases, mainly NDs. Finally, we propose potential drug compounds targeting S-palmitoylation.

Multiple post-translational modifications ensure EGFR functionality: Potential therapeutic targets to overcome its drug-resistance mutations.

Epidermal growth factor receptor (EGFR) mutation is the most common driver mutation in non-small cell lung cancer (NSCLC). The first-line therapy for advanced NSCLC patients with EGFR-sensitive mutation is the EGFR tyrosine kinase inhibitor (EGFR-TKI). However, most NSCLC patients with EGFR mutation will develop resistant mutations in EGFR-TKI therapy. With further studies, resistance mechanisms represented by EGFR-T790M mutations have revealed the impact of EGFR mutations in situ on EGFR-TKIs sensitivity. The third-generation EGFR-TKIs inhibit both EGFR-sensitive mutations and T790M mutations. The emergence of novel mutations such as EGFR-C797S and EGFR-L718Q may decrease efficacy. Searching for new targets to overcome EGFR-TKI resistance becomes a key challenge. Therefore, an in-depth understanding of the regulatory mechanisms of EGFR is essential to find novel targets to overcome drug-resistant mutations in EGFR-TKIs. EGFR, as a receptor-type tyrosine kinase, undergoes homo/heterodimerization and autophosphorylation upon binding to ligands, which activates multiple downstream signaling pathways. Interestingly, there is growing evidence that the kinase activity of EGFR is affected not only by phosphorylation but also by various post-translational modifications (PTMs, such as S-palmitoylation, S-nitrosylation, Methylation, etc.). In this review, we systematically review the effects of different protein PTMs on EGFR kinase activity and its functionality and suggest that influencing EGFR kinase activity by modulating multiple EGFR sites are potential targets to overcome EGFR-TKIs resistance mutations.

HSP90ß chaperoning SMURF1-mediated LATS proteasomal degradation in the regulation of bone formation.

Heat shock protein 90 (HSP90) molecular chaperone is responsible for the stabilization and biological activity of a diverse set of client proteins. We have previously demonstrated that inhibition of HSP90 by 17-Demethoxy-17-allyaminogeldanmycin (17-AAG) not only reverses the glucocorticoid-induced bone loss but also enhances the basal level of bone mass in mice. Here, we investigate the potential mechanism underlying HSP90-associated osteoblast differentiation and bone formation. Knockdown of HSP90ß but not HSP90α or inhibition of HSP90 by 17-AAG or NVP-BEP800 negates the protein levels of large tumor suppressor (LATS), the core kinases of Hippo signaling, resulting in the inactivation of LATS and activation of Yes-associated protein (YAP) and transcriptional coactivator with PDZ-binding motif (TAZ), in the enhancement of osteoblastic differentiation. In contrast, genetic ablation of Lats1 in mesenchymal stem cells is sufficient to abolish the HSP90 inhibition-induced osteoblastic differentiation and bone formation. Mechanistically, HSP90ß but not HSP90α chaperones and prevents the SMAD specific E3 ubiquitin protein ligase 1 (SMURF1)-mediated and ubiquitination-dependent LATS protein proteasomal degradation, whereas 17-AAG abolishes these effects of HSP90ß. Thus, these results uncover the HSP90ß chaperoning SMURF1-mediated LATS protein proteasomal degradation and the subsequent YAP/TAZ activation as a hitherto uncharacterized mechanism controlling osteoblastic differentiation and bone formation.

Suppression of VEGFD expression by S-nitrosylation promotes the development of lung adenocarcinoma.

BACKGROUND: Vascular endothelial growth factor D (VEGFD), a member of the VEGF family, is implicated in angiogenesis and lymphangiogenesis, and is deemed to be expressed at a low level in cancers. S-nitrosylation, a NO (nitric oxide)-mediated post-translational modification has a critical role in angiogenesis. Here, we attempt to dissect the role and underlying mechanism of S-nitrosylation-mediated VEGFD suppression in lung adenocarcinoma (LUAD). METHODS: Messenger RNA and protein expression of VEGFD in LUAD were analyzed by TCGA and CPTAC database, respectively, and Assistant for Clinical Bioinformatics was performed for complex analysis. Mouse models with urethane (Ure)-induced LUAD or LUAD xenograft were established to investigate the role of S-nitrosylation in VEGFD expression and of VEGFD mutants in the oncogenesis of LUAD. Molecular, cellular, and biochemical approaches were applied to explore the underlying mechanism of S-nitrosylation-mediated VEGFD suppression. Tube formation and wound healing assays were used to examine the role of VEGFD on the angiogenesis and migration of LUAD cells, and the molecular modeling was applied to predict the protein stability of VEGFD mutant. RESULTS: VEGFD mRNA and protein levels were decreased to a different extent in multiple primary malignancies, especially in LUAD. Low VEGFD protein expression was closely related to the oncogenesis of LUAD and resultant from excessive NO-induced VEGFD S-nitrosylation at Cys277. Moreover, inhibition of S-nitrosoglutathione reductase consistently decreased the VEGFD denitrosylation at Cys277 and consequently promoted angiogenesis of LUAD. Finally, the VEGFDC277S mutant decreased the secretion of mature VEGFD by attenuating the PC7-dependent proteolysis and VEGFDC277S mutant thus reversed the effect of VEGFD on angiogenesis of LUAD. CONCLUSION: Low-expression of VEGFD positively correlates with LUAD development. Aberrant S-nitrosylation of VEGFD negates itself to induce the tumorigenesis of LUAD, whereas normal S-nitrosylation of VEGFD is indispensable for its secretion and repression of angiogenesis of LUAD.

SUMOylation activates large tumour suppressor 1 to maintain the tissue homeostasis during Hippo signalling.

Large tumour suppressor (LATS) 1/2, the core kinases of Hippo signalling, are critical for maintaining tissue homeostasis. Here, we investigate the role of SUMOylation in the regulation of LATS activation. High cell density induces the expression of components of the SUMOylation machinery and enhances the SUMOylation and activation of Lats1 but not Lats2, whereas genetic deletion of the SUMOylation E2 ligase, Ubc9, abolishes this Lats1 activation. Moreover, SUMOylation occurs at the K830 (mouse K829) residue to activate LATS1 and depends on the PIAS1/2 E3 ligase. Whereas the K830 deSUMOylation mutation of LATS1 found in the human metastatic prostate cancers eliminates the kinase activity by attenuating the formation of the phospho-MOB1/phospho-LATS1 complex. As a result, the LATS1(K830R) transgene phenocopies Yap transgene to cause the oversized livers in mice, whereas Lats1(K829R) knock-in phenocopies the deletion of Lats1 in causing the reproductive and endocrine defects and ovary tumours in mice. Thus, SUMOylation-mediated LATS1 activation is an integral component of Hippo signalling in the regulation of tissues homeostasis.

The amino acid sensor general control nonderepressible 2 (GCN2) controls TH9 cells and allergic airway inflammation.

BACKGROUND: TH9 cells have emerged as important mediators of allergic airway inflammation. There is evidence that general control nonderepressible 2 (GCN2) affects the immune response under some stress conditions. However, whether GCN2 regulates CD4+ T-cell differentiation during allergic inflammation remains unknown. OBJECTIVE: We sought to clarify the regulatory roles of GCN2 in CD4+ T-cell subset differentiation and its significance in patients with allergic airway inflammation. METHODS: The effects of GCN2 in differentiation of TH cell subsets were detected by using the in vitro induction system. GCN2 knockout mice, ovalbumin-induced allergic airway inflammation, and adoptive transfer mouse models were used to determine the significance of GCN2 in TH9 differentiation and allergic airway inflammation in vivo. RNA sequencing, real-time PCR, Western blotting, and other molecular approaches were used to identify the molecular mechanisms relevant to regulation of GCN2 in TH9 cell differentiation. RESULTS: GCN2 deficiency significantly inhibited differentiation of TH9 cells but not TH1, TH2, and regulatory T cells. GCN2 knockout mice and recombination-activating gene 2 knockout (Rag2KO) mice that received adoptively transferred GCN2-deficient CD4+ T cells exhibited reduced TH9 differentiation and less severe allergic airway inflammation. Furthermore, the isolated GCN2-deficient TH9 cells also mediated less severe allergic airway inflammation on adoptive transfer. Mechanistically, GCN2 deficiency inhibits TH9 cell differentiation through a hypoxia-inducible factor 1α-dependent glycolytic pathway. CONCLUSION: Our results reveal a novel role of GCN2 in TH9 cell differentiation. Our findings indicate that new strategies to inhibit GCN2 activity might provide novel approaches to attenuate allergic airway inflammation.