Molecular and cellular pruritus mechanisms in the host skin.

Pruritus, also known as itching, is a complex sensation that involves the activation of specific physiological and cellular receptors. The skin is innervated with sensory nerves as well as some receptors for various sensations, and its immune system has prominent neurological connections. Sensory neurons have a considerable impact on the sensation of itching. However, immune cells also play a role in this process, as they release pruritogens. Disruption of the dermal barrier activates an immune response, initiating a series of chemical, physical, and cellular reactions. These reactions involve various cell types, including keratinocytes, as well as immune cells involved in innate and adaptive immunity. Collective activation of these immune responses confers protection against potential pathogens. Thus, understanding the molecular and cellular mechanisms that contribute to pruritus in host skin is crucial for the advancement of effective treatment approaches. This review provides a comprehensive analysis of the present knowledge concerning the molecular and cellular mechanisms underlying itching signaling in the skin. Additionally, this review explored the integration of these mechanisms with the broader context of itch mediators and the expression of their receptors in the skin.

B7-H4 expression promotes non-small cell lung cancer progression via AMPK/mTOR signaling.

Several studies have demonstrated that B7-H4 is highly expressed in a variety of cancers and often affects tumor development. However, its role in cancer stemness and epithelial-to-mesenchymal transition (EMT) in non-small cell lung cancer (NSCLC) has not been reported. Here, we investigated the relationship between B7-H4 expression and cancer stemness and EMT by immunohistochemistry in 106 NSCLC tissues obtained from patients. The results confirmed that B7-H4 is highly expressed in NSCLC tissues and closely correlated with the expression of EMT-related proteins (Snail, Vimentin) and cancer stemness-related proteins (SOX2, SOX9, and CD44). Immunofluorescence assay indicated that B7-H4 colocalized with SOX2 and SOX9 in the nuclei of NSCLC cells. Additionally, upon knocking down B7-H4, the expression of SOX2, SOX9, and CD44, as well as of Snail and Vimentin was inhibited, whereas E-cadherin expression was enhanced in NSCLC cells. Meanwhile, inhibiting the expression of B7-H4 resulted in reduced invasion and migration ability of NSCLC cells. Mechanistically, silencing B7-H4 activated the adenosine monophosphate-activated protein kinase /mammalian target of rapamycin signaling, which in turn, negatively regulated cell proliferation, stemness, and migration. In conclusion, our results suggest that B7-H4 expression is high in NSCLC tissues, and it has an effect on EMT and cancer stemness. This further suggests that B7-H4 has a potential role in promoting the progression of NSCLC and thereby could be a potential therapeutic target in NSCLC treatment.

SETD8 is a prognostic biomarker that contributes to stem-like cell properties in non-small cell lung cancer.

SETD8 is a lysine methyltransferase containing an SET domain and has been reported to regulate various biological processes, including carcinogenesis. However, its prognostic value and mechanisms of action in non-small cell lung cancer (NSCLC) have not been extensively studied. Here, we assessed SETD8 expression and its relationship with clinicopathological parameters, cancer stemness proteins, and cell cycle-regulating proteins in NSCLC. SETD8 expression in NSCLC tissues was correlated with primary tumor stage, lymph node metastases, and clinical stage. Moreover, SETD8 was an independent predictor of poor overall survival in NSCLC. A Cox regression analysis showed that SETD8 was a potential biomarker of unfavorable clinical outcomes in patients with NSCLC. SETD8 overexpression was associated with cancer stemness-related genes and cell cycle-related genes in NSCLC tissue samples. SETD8 silencing significantly reduced the expression of cancer stemness-associated genes (CD44, LGR5, and SOX2) and inhibited NSCLC cell proliferation, spheroid formation, invasion, and migration. Our findings demonstrate that SETD8 may be a novel cancer stemness-associated protein and a potential prognostic biomarker in NSCLC.

SETD8 promotes stemness characteristics and is a potential prognostic biomarker of gastric adenocarcinoma.

SETD8 is a lysine methyltransferase containing an SET domain, which is involved in the carcinogenesis of many cancer types through monomethylation of the histone H4 lysine 20. However, its prognostic value and underlying mechanisms in gastric adenocarcinoma (GA) have not been extensively studied. Here, we assessed SETD8 expression and its relationship with clinicopathological parameters, cancer stemness-related proteins, cell cycle-related proteins, and PI3K/Akt pathway proteins in GA. SETD8 expression in GA tissues was correlated with the primary tumor stage, lymph node metastasis, tumor size, gross type, and clinical stage. SETD8 was an independent predictor of poor overall survival of patients with GA. Cox regression analysis showed that SETD8 is a potential biomarker of unfavorable clinical outcomes in patients with GA. Moreover, SETD8 overexpression was associated with cancer stemness-related genes, cell cycle-related genes, and PI3K/Akt/NF-κB pathway genes in clinical GA tissue samples. SETD8 silencing downregulated the expression of cancer stemness-associated genes (LSD1 and SOX2) and inhibited GA cell proliferation, spheroid formation, invasion, and migration. Additionally, LY294002 significantly reduced the expression of SETD8, pAkt-Ser473, pPI3K-p85, and NFκB-p65 in MKN74 and MKN28 cells. SETD8 may be a novel cancer stemness-associated protein and potential prognostic biomarker in GA.

Leucine Zipper-EF-Hand Containing Transmembrane Protein 1 Is a Potential Prognostic Biomarker and Promotes Cell Progression in Prostate Cancer.

PURPOSE: The leucine zipper-EF-hand containing transmembrane protein 1 (LETM1) is a mitochondrial protein that has been associated with the occurrence and development of malignant tumors. Previous studies have shown that LETM1 expression is increased in several types of human cancer and is associated with a poor clinical outcome. However, the role of LETM1 in prostate cancer (PCa) has not yet been determined. In this study, we investigated the clinicopathological significance of LETM1 expression and its role in PCa progression. METHODS: We assessed the expression of LETM1 and genes related to cancer stemness, epithelial-mesenchymal transition (EMT), cell cycle, and PI3K/Akt signaling in 133 paraffin-embedded PCa tissue samples and cancer cells by using immunohistochemistry, immunofluorescence, and Western blotting. RESULTS: LETM1 expression was significantly increased in PCa, and it was positively correlated with Gleason score, pathologic tumor (pT) stage, clinical stage, and high microvessel density. Survival analysis showed that patients with PCa with a high level of LETM1 expression exhibited a low overall survival. Cox regression analysis indicated that LETM1 is an independent poor prognostic PCa factor. Additionally, the expression of LETM1 was correlated with cancer cell stemness-associated genes, EMT-related genes, cell cycle regulatory genes, and PI3K/Akt signaling gene expression in PCa. Furthermore, knocking down LETM1 expression down-regulated the expression of stemness-related proteins, while inhibiting tumor spheroid formation, EMT-like changes, cell proliferation, migration, and invasion in PCa cells. Importantly, the PI3K inhibitor LY294002 strongly inhibited the expression of LETM1, pPI3K-p85, and pAkt (Thr308, Ser473) in PCa cells. CONCLUSION: These results indicate that LETM1 expression is associated with cancer cell stemness, promotes EMT-like changes and cell proliferation and is a potential prognostic biomarker for PCa.

B7-H4 is a potential prognostic biomarker of prostate cancer.

B7-H4 is a member of B7 family which regulates immune responses by delivering costimulatory signals. However, it negatively regulates T cell-mediated immunity and may play an important role in tumor immune evasion. Although several studies have been reported that expression of B7-H4 is elevated in the several types of human cancer with a poor clinical outcome, its clinical significance in the prostate cancer (PCa) has not been well studied. In this study, we investigated the clinical significance of B7-H4 in human PCa and determined if B7-H4 expression is associated with the cancer cell stemness in PCa. Our studies show that expression of B7-H4 is correlated with the pathologic tumor (pT) stage and the clinical stage of PCa. The Kaplan-Meier survival analysis revealed that PCa patients with high expression of B7-H4 exhibits a shorter overall survival (OS) rate. Univariate and multivariate Cox regression analysis indicated that B7-H4 is an independent poor prognostic factor of PCa. In addition, the expression of B7-H4 is correlated with the cancer cell stemness associated genes expression in PCa. Further, our studies show that B7-H4 regulates cancer cell stemness associated genes expression and effects on the cell cycle and PI3K/Akt signaling related genes expression in PCa. These results indicate that B7-H4 expression is associated with cancer cell stemness, and B7-H4 is a potential prognostic biomarker and a therapeutic target of PCa.

SET domain-containing 5 is a potential prognostic biomarker that promotes esophageal squamous cell carcinoma stemness.

SET domain-containing 5 (SETD5) is an uncharacterized member of the protein lysine methyltransferase family. Although it was reported that SETD5 gene mutations are associated with the several types of human cancer, its functional role in esophageal squamous cell carcinoma (ESCC) progression has not been fully elucidated. In the present study, we used tissue samples from 147 patients with ESCC and ESCC cell lines to determine the clinicopathological significance of SETD5 in ESCC and its effects on ESCC stemness. We performed immunohistochemical staining, immunofluorescence imaging, and tumor sphere formation, colony formation, flow cytometry, wound healing, Transwell, and western blotting assays. SETD5 expression was upregulated in ESCC tissue and associated with primary tumor (pT) stage, clinical stage, lymph node metastasis, shorter overall survival rate, and disease-free survival rate. Cox regression analyses indicated that SETD5 is an independent poor prognostic factor of ESCC. In addition, SETD5 expression was correlated with cancer stemness-related protein, hypoxia-inducible factor-1α (HIF-1α), and CD68 expression. Moreover, immunofluorescence analysis revealed that SETD5 was co-localized with CD44 and SOX2 in TE10 and TE11 cells and that exposing cells to cobalt chloride increased HIF-1α, SETD5, and stemness-related protein expression in a time-dependent manner. Furthermore, SETD5 expression was significantly correlated with the expression of cell cycle-related genes and PI3K/Akt signaling pathway-related proteins. Finally, knocking down SETD5 downregulated the expression of stemness-related and PI3K/Akt signaling pathway proteins, while inhibiting tumor spheroid formation, cell proliferation, migration, and invasion in ESCC cells. These results indicate that SETD5 expression is associated with cancer stemness and that SETD5 is a potential prognostic biomarker and therapeutic target for ESCC.

Mechanism of CNP-mediated DG-PKC and IP4 signaling pathway in diabetic rats with gastric motility disorder.

In the precedent research conducted by the same team, it concluded that the activities in C-type natriuretic peptide (CNP)/cyclic guanosine monophosphate (cGMP)/cyclic adenosine monophosphate (cAMP)/ß-type phospholipase C (PLCß) pathways of rat antral smooth muscle were changed due to diabetes, which was the key pathogenetic mechanism for diabetic gastric dysmotility. As the follow-on step, this study was designed to probe into the downstream signaling pathway of CNP/PLCß. The results showed that level of α-type protein kinase C (PKCα),cell membrane to cytoplasm ratio of PKCα, cell membrane to cytoplasmic ratio of ßI-type protein kinase C (PKCßI) and level of Phosphor-PKCα (P-PKCα) were significantly reduced in diabetes rat antral smooth muscle samples. The content of tetraphosphate inositol (IP4) in gastric antral smooth muscle of diabetic rats reduced, and the content of diacyl-glycerol (DG) was unchanged. CNP significantly decreased the content of IP4 and DG, this effect was more obvious in diabetic rats. Subsequent to the addition of protein kinase A (PKA) blocker N-[2- (p-Bromocin-namylamino)ethyl]-5 -isoquinolinesulfonamide dihydrochloride (H-89) before CNP treatment, the inhibitory effect of CNP was reduced; subsequent to the addition of protein kinase G (PKG) blocker KT5823 before CNP treatment, the inhibitory effect of CNP was also reduced. With the addition of the combination of H-89 and KT5823 before CNP treatment, the inhibition by CNP could be offset. These results were concluded that CNP inhibited the activity of PKC family in rat smooth muscle and reduced the levels of IP4 and DG through the PKG/PKA-PLCß pathways, causing inhibited muscular contractions, which may be a key pathogenetic factor for diabetic gastroparesis.

LETM1 is a potential biomarker that predicts poor prognosis in gastric adenocarcinoma.

Leucine zipper-EF-hand containing transmembrane protein 1 (LETM1) is closely linked to the occurrence and development of many malignant tumors. Many studies have reported that enhanced expression of LETM1 in several types of human cancers was associated with poor clinical outcomes; however, its clinical significance in gastric adenocarcinoma (GA) has not been elucidated. In this study, we assessed the expression of LETM1 along with the genes related to cancer stemness, cell cycle, and PI3K/Akt signaling in 189 paraffin-embedded GA tissue samples and GA-derived cell lines using immunohistochemistry (IHC), western blotting, and immunofluorescence. Our results showed that the expression of LETM1 was strongly correlated with the tumor grade, primary tumor (pT) stage, lymph node metastasis, clinical stage, and tumor gross type of GA. The Kaplan-Meier survival analysis revealed that patients with GA with high expression of LETM1 exhibit a shorter overall survival (OS) rate. Univariate and multivariate Cox regression analysis indicated that LETM1 is an independent poor prognostic factor of GA. Significantly, LETM1 expression was positively correlated with the expression of cancer stemness-related genes such as CD44 and LGR5 and expression of cell-cycle related gene, cyclin D1. Further, the expression of proteins involved in PI3K/Akt signaling pathway, such as pPI3K-p85 and pAkt-Thr308, was also increased. Additionally, small interfering RNA (esiRNA)-mediated silencing of LETM1 expression in GA-derived cell lines MKN28 and MKN74 strongly inhibited the expression of stemness and cell cycle-related proteins, suppressed cancer cell spheroid formation, migration and invasion ability, and affected cell cycle distribution. Furthermore, the GA-derived cell line AGS exhibited enhanced expression of LETM1, CD44, LGR5, and HIF1-α under hypoxic conditions. Lastly, we blocked PI3K expression using an inhibitor LY294002, which downregulated the expression of LETM1, pPI3K-p85, and pAkt-Thr308. Taken together, our results demonstrate that LETM1 regulates cell proliferation and promotes tumorigenicity of GA, and its overexpression is associated with the poor progression of GA. Therefore, LETM1 could serve as a potential prognostic biomarker and a therapeutic target for the better clinical management of GA.

Macelignan inhibits the inflammatory response of microglia and regulates neuronal survival.

Neuroinflammation is an important pathological process of neurodegenerative diseases, and microglial contributes to chronic inflammation and neuronal loss in progressive neurodegenerative. Therefore, regulating the inflammatory response of microglia could lead to the discovery of promising treatments for neurodegenerative diseases. In this study, we investigated the effects of the nutmeg plant seed extract, macelignan, on the inflammatory response of microglia and neuronal cell survival. We detected NO and iNOS using the Griess test and Western blotting. We measured phosphoinositide 3 kinase (PI3K)/Akt expression by Western blotting. The release of NO and inflammatory cytokines and the expression of iNOS decreased in a concentration-dependent manner, with an increase in macelignan concentration. PI3K/Akt phosphorylation levels decreased in a dose-dependent manner in lipopolysaccharide (LPS)-activated microglial cells after exposure to macelignan. We also demonstrated that macelignan improved HT22 cell viability, following exposure to a microglial-conditioned medium. Furthermore, macelignan inhibited microglial cell near neurons treated with a hypoxic conditioned medium. Finally, macelignan treatment reduced the expression of p27 and cyclin D1 in neurons cultured in an LPS-activated microglia-conditioned medium. Therefore, these results imply that macelignan can inhibit the inflammatory response of microglia and regulate neuronal survival through the PI3K/Akt pathway.

LETM1 is a potential cancer stem-like cell marker and predicts poor prognosis in colorectal adenocarcinoma.

The leucine zipper-EF-hand containing transmembrane protein 1 (LETM1) is highly expressed in many human malignancies and is correlated with poor prognosis. However, LETM1 has rarely been explored as a cancer stem-like cell marker for the prognostic evaluation of colorectal adenocarcinoma (CRA). Herein, we assessed the expression of LETM1 and its relationship with cancer stemness genes, cell cycle markers, PI3K/Akt/NFκB signaling pathway genes, and HIF1α in 102 paraffin-embedded CRA tissue samples using immunohistochemistry (IHC). Additionally, we further confirmed the correlation between LETM1 and cancer stemness genes in CRA cell lines using immunofluorescence (IF) imaging and Western blotting. LETM1 expression was remarkably upregulated in human fetal sagittal sections and CRA tissues. The expression of LETM1 in CRA tissue was correlated with clinical stage, lymph node metastasis, distant metastasis, and microvessel density. LETM1 expression was significantly associated with lower overall survival and disease-free survival. Moreover, the expression of LETM1 positively correlated with SOX9, LSD1, CD44, CD133, LGR5, SOX2, and HIF1α. IF revealed that LETM1 co-localized with CD44, SOX9, and LGR5 in HCT116. Moreover, LETM1 expression was also strongly linked to the expression of cell cycle regulators (cyclinD1, CDK4, p27) and PI3K/Akt/NFκB pathway genes (pPI3K-p85, pAkt-Ser473, pAkt-Thr308, pNFκB-p65). LETM1 may therefore be a cancer stem-like cell marker and an indicator of poor prognosis in patients with CRA.

The role of CNP-mediated PKG/PKA-PLCß pathway in diabetes-induced gastric motility disorder.

Our previous work demonstrated that the C-type natriuretic peptide (CNP)/cyclic guanosine monophosphate (cGMP)/cyclic adenosine monophosphate (cAMP) pathway in gastric antrum smooth muscle of rats with diabetes was upregulated and played an important role in the development of diabetic gastric dysmotility. Our goal for this study was to explore the downstream signaling pathways of CNP. We found that the expressions of protein kinase G (PKG) and protein kinase A (PKA) in gastric smooth muscle tissue of rats with diabetes were significantly upregulated. The expressions of ß-type phospholipase C 3(PLCß3) and ß-type phospholipase C 1(PLCß1) protein were reduced, whereas Phosphor-PLCß3Ser1105 (P-PLCß3Ser1105) was increased. The inhibitory effect of CNP on gastric antral smooth muscle in diabetic rats was significantly greater than in the normal group. The content of trisphosphate inositol (IP3) in the gastric antral smooth muscle of rats with diabetes was significantly lower than that of the normal group. After blocking PKA with N-[2-(p-Bromocinnamylamino)ethyl]-5-isoquinolinesulfonamide dihydrochloride (H-89, a blockage PKA), the effect of CNP on the production of IP3 was decreased, while blocking PKG with KT5823 (a blockage PKG) simultaneously, and CNP can no longer reduce the IP3 production. CNP promoted the phosphorylation of PLCß3Ser1105, thereby inhibiting the activity of PLCß3 in gastric smooth muscle tissue of rats with diabetes; this effect can be abolished by blocking PKA and PKG. These results suggested that CNP can decrease IP3 level in gastric smooth muscle cells and thus inhibit gastric smooth muscle contraction through PKG/PKA-PLCß pathway, which may play an important role in the development of diabetic gastroparesis.

Significance of dynamic changes in gastric smooth muscle cell apoptosis, PI3K-AKT-mTOR and AMPK-mTOR signaling in a rat model of diabetic gastroparesis.

The aim of the present study was to investigate the significance of cell apoptosis, the phosphoinositide-3-kinase (PI3K)-protein kinase B (AKT)-mammalian target of rapamycin (mTOR) pathway, and the 5' adenosine monophosphate-activated protein kinase (AMPK)­mTOR pathways in the process of diabetic gastroparesis. Changes in gastric smooth muscle cells of diabetic rats with induced gastroparesis were examined. The diabetic rat model was established by dividing animals into a normal control group and diabetic model groups examined at 2, 4 and 6 weeks. Diabetic gastroparesis was evaluated by examining the rates of gastric residual pigment, whereas flow cytometry was used to detect the apoptosis of gastric smooth muscle cells. The expression levels of PI3K and phosphorylated (p­) AKT, AMPK, mTOR, tuberous sclerosis complex 2, p70 ribosomal S6 kinase, and eukaryotic translation initiation factor 4­binding protein 1 were determined in gastric muscles using western blot analysis. Diabetic gastroparesis was confirmed in models at 6 weeks. The apoptosis of gastric smooth muscle cells gradually increased in all diabetic groups, and significant changes were observed in key proteins involved in PI3K­AKT­mTOR and AMPK­mTOR signaling. The results indicated that apoptosis was important in the occurrence of diabetic gastroparesis, and the PI3K­AKT­mTOR and AMPK­mTOR pathways were activated during the apoptotic processes, but were incapable of regulating apoptosis.

CNP-pGC-cGMP-PDE3-cAMP Signal Pathway Upregulated in Gastric Smooth Muscle of Diabetic Rats.

Our previous studies have shown that CNP-NPR-B/pGC-cGMP is upregulated in the diabetic rats. The present study was designed to determine whether the upregulation of CNP-NPR-B/pGC-cGMP signal pathway affects cGMP-PDE3-cAMP signal pathway in diabetic gastric smooth muscle. The gastric smooth muscle motility was observed by using isometric measurement. PDEs expressions in diabetic gastric smooth muscle tissue were observed by using immunohistochemistry, Western blotting, and RT-PCR methods. The results demonstrated that the inhibitory effect of CNP on the spontaneous contraction of gastric antral circular smooth muscle was potentiated in STZ-induced diabetic rat. CNP-induced increase of cGMP and cAMP was much higher in diabetic gastric smooth muscle tissue than in controls. The expression of PDE3 is downregulated while the levels of gene expression of PDE1, PDE2, PDE4, and PDE5 were not altered in the diabetic gastric smooth muscle tissue. The results suggest that the sensitivity of gastric smooth muscle to CNP is potentiated via activation of CNP-pGC-cGMP-PDE3-cAMP signal pathway in STZ-induced diabetic rats, which may be associated with diabetes-induced gastric motility disorder.

[Forskolin inhibits spontaneous contraction of gastric antral smooth muscle in rats].

The aim of the present study was to investigate the effects of cyclic adenosine monophosphate (cAMP) on rat gastric antral circular smooth muscle function. Forskolin, a direct activator of adenylyl cyclase (AC), was used to observe the influences of cAMP. Multi-channel physiological recorder was used to record spontaneous contraction activity of gastric antral circular muscle from Wistar rats. And ELISA method was used to detect the change of cAMP production in perfusate. The results showed that forskolin concentration-dependently suppressed the amplitude and frequency of the spontaneous contraction of the gastric antral muscle, and lowered the baseline of contraction movement significantly. Forskolin concentration-dependently increased the production of cAMP in the perfusate, which showed a significant negative correlation with the contraction amplitude of gastric antral ring muscle. The inhibitory effect of forskolin on spontaneous contraction activity of rat gastric antral circular muscle could be blocked by cAMP-dependent protein kinase (PKA) inhibitor H-89. These results suggest forskolin increases cAMP production and then activates PKA pathway, resulting in the inhibition of the spontaneous contraction activity of rat gastric antral circular smooth muscle.

cGMP-PDE3-cAMP signal pathway involved in the inhibitory effect of CNP on gastric motility in rat.

In the present study, we investigated the mechanism of C-type natriuretic peptide (CNP)-induced inhibitory effect on spontaneous contraction of gastric antral smooth muscle to clarify CNP-NPR-B/pGC-cGMP downstream signal transduction pathway using organ bath and ELISA methods in rat. CNP significantly reduced the amplitude of the spontaneous contraction and increased the contents of cGMP and cAMP in the gastric antral smooth muscle tissue. In the presence of IBMX, a non-selective phosphodiesterase (PDE) inhibitor, the inhibitory effect of CNP on spontaneous contraction was significantly suppressed; however, the production of cGMP but not cAMP was still increased by CNP. EHNA, a PDE2 inhibitor, did not affect both CNP-induced inhibition of the contraction and CNP-induced increase of cGMP and cAMP generations in gastric smooth muscle tissue, while milrinone, a PDE3 inhibitor, similar to IBMX, attenuated the CNP-induced inhibitory effect on spontaneous contraction and increased the content of cGMP but not cAMP. The results suggest that cGMP-PDE3-cAMP signal pathway is also involved in the CNP-induced inhibition of gastric motility in rat.