Keratin Research Articles

Identifying amyloid-related diseases by mapping mutations in low-complexity protein domains to pathologies

Proteins including FUS, hnRNPA2, and TDP-43 reversibly aggregate into amyloid-like fibrils through interactions of their low-complexity domains (LCDs). Mutations in LCDs can promote irreversible amyloid aggregation and disease. We introduce a computational approach to identify mutations in LCDs of disease-associated proteins predicted to increase propensity for amyloid aggregation. We identify several disease-related mutations in the intermediate filament protein keratin-8 (KRT8). Atomic structures of wild-type and mutant KRT8 segments confirm the transition to a pleated strand capable of amyloid formation. Biochemical analysis reveals KRT8 forms amyloid aggregates, and the identified mutations promote aggregation. Aggregated KRT8 is found in Mallory–Denk bodies, observed in hepatocytes of livers with alcoholic steatohepatitis (ASH). We demonstrate that ethanol promotes KRT8 aggregation, and KRT8 amyloids co-crystallize with alcohol. Lastly, KRT8 aggregation can be seeded by liver extract from people with ASH, consistent with the amyloid nature of KRT8 aggregates and the classification of ASH as an amyloid-related condition.

Promoter Methylation Changes in KRT17: A Novel Epigenetic Marker for Wool Production in Angora Rabbit.

Wool production is an important economic trait of Angora rabbits. Exploring molecular markers related to wool production is one of the essentials of Angora rabbits’ breeding. KRT17 (Keratin 17) is an important gene of hair follicle development, which must be explored for genetic/epigenetic variation to assess its effect on wool production. Based on the effective wool production data of 217 Angora rabbits, the high and low yield groups were screened with 1.5 standard deviations of the population mean. The full-length sequence of KRT17 was obtained by rapid amplification of cDNA ends technology, and the polymorphism was analyzed in the promoter, exon, and intron regions by direct sequencing. KRT17, SP1 over-expression plasmids, and siRNA were constructed and transfected into dermal papilla cells. The mRNA expressions of relevant genes were analyzed by RT-qPCR. The methylation level of the KRT17 promoter was determined by Bisulfite Sequencing PCR. Dual-luciferase system, site-directed mutagenesis, and electrophoretic mobility shift assays were used to analyze the binding relationship between SP1 and the promoter of KRT17. The structure map of KRT17 was drawn, and no SNPs were found in the promoter, exon, and intron, indicating a relatively conserved structure of KRT17. Expression of KRT17 was significantly higher in cutaneous tissues than in other tissues and was significantly upregulated in the high-yield group compared to the low-yield group (p < 0.05). Furthermore, the overall high methylation levels of KRT17 CpG I and CpG III showed significant association with low wool yield; the methylation levels of 5 CpG locus (CpG I site 4 and CpG III site 2–5) were significantly different between the high and low yield groups (p < 0.05). The methylation levels of 3 CpG locus (CpG I site 4 and CpG III site 4, 14) showed a significant correlation with KRT17 expression (p < 0.05). Overall, CpG III site 4 significantly affects wool production and KRT17 expressions (p < 0.05). This site promotes SP1 binding to the KRT17 promoter region (CGCTACGCCC) to positively regulate the KRT17 expression. KRT17 CpG III site 4 can be used as candidate epigenetic markers for the breeding of high wool-producing Angora rabbits.

KRT8 Serves as a Novel Biomarker for LUAD and Promotes Metastasis and EMT via NF-κB Signaling

Keratin 8 (KRT8) is the major component of the intermediate filament cytoskeleton and aberrant expression in multiple tumors. However, the role of KRT8 in lung adenocarcinoma (LUAD) remains unclear. In the present study, KRT8 expression was found to be upregulated along with prognosis and metastasis in LUAD. Kaplan–Meier analysis presented that the 5-year OS and DSS rates were significantly better among patients with low KRT8 expression compared to those with high expression. Correlation analysis showed that KRT8 expression was significantly associated with gender (P = 0.027), advanced T stage (P = 0.001), advanced N stage (P = 0.048), and advanced pathologic stage (P = 0.025). Univariate Cox analysis demonstrated that KRT8 was a predictor of OS [hazard ratio (HR) = 1.526; 95% confidence interval (CI) 1.141–2.040; P = 0.004] and DSS (HR = 1.625; 95% CI 1.123–2.353; P = 0.010) in the TCGA database. Importantly, downregulation of KRT8 obviously suppressed cell proliferation, cell migration, invasion, and EMT as well as induced cell apoptosis. KRT8 knockdown significantly inhibited NF-κB signaling, suggesting a potential mechanism. Overall, our results indicated that KRT8 could regulate lung carcinogenesis and may serve as a potential target for antineoplastic therapies.

Co‐expression of Zeb‐1 and K17 provides new insights into the role of EMT in pancreatic cancer progression

INTRODUCTIONDespite improvements in screening and therapeutic options, pancreatic ductal adenocarcinoma (PDAC) has the third‐worst mortality rate, highlighting the need for better diagnostic and therapeutic approaches. Epithelial‐mesenchymal transition (EMT) has been conferred with a greater likelihood of metastasis in multiple cancers, specifically identified through markers like Zeb‐1 and Twist‐1. Zeb‐1 (Zinc Finger E‐Box Binding Homeobox 1) was shown to repress E‐cadherin expression, consequently inducing EMT.Our lab has previously identified K17 (Keratin 17) as an independent prognostic biomarker of poor outcomes in PDAC patients. While increasing evidence has suggested that EMT drives pancreatic cancer migration and metastasis, there have not been any well‐established connections between K17 expression and EMT. This study aims to provide new insights into the role of K17 in EMT by evaluating the co‐expression of K17 and Zeb‐1 in human PDAC biopsies. We hypothesized that tumor cells co‐express K17 and Zeb‐1 as a hallmark of EMT in PDAC. In addition, our study aims to establish a novel method of scoring Zeb‐1 expression in stromal fibroblasts via immunofluorescence to remove variability in the stromal constituency.METHODSPDAC tissues obtained from patients who underwent surgical resection between 2013 and 2017 at Stony Brook University (n=20) were selected for serial sectioning. Double immunofluorescence and single immunohistochemical staining were achieved by incubation with Zeb‐1 and K17 antibodies followed by incubation of fluorescent or biotin conjugated secondary antibodies, respectively. Histologic examination was performed using immunofluorescence staining along with H&amp;E and immunohistochemical staining (IHC) to determine concordance.RESULTS● IHC for Zeb‐1 was detected predominantly in the nuclei of centroacinar cells, benign proliferative ducts, and stromal fibroblasts. Focal nuclear staining in tumor epithelial was also detected in some cases.● High levels of K17 and but decreased expression of Zeb‐1 were detected in diffusely infiltrative cells with morphologic features of EMT.● Both high Zeb‐1 and high K17 protein expression were associated with poor survival of PDAC patients.● Using confocal immunofluorescence microscopy, we detected co‐localization of Zeb‐1 and K17 in PDAC.● We quantified Zeb‐1 protein expression in PDAC samples from 20 patients and confirmed significantly higher expression in the tumor‐associated stroma of high‐grade tumors compared to stromal fibroblasts in areas devoid of tumor.CONCLUSIONOur results provide evidence that K17 is upregulated in tumor epithelial cells that show morphologic immunohistochemical properties of EMT. The loss of Zeb‐1 in diffusely infiltrative, K17‐positive tumor cells suggests that EMT upregulates K17, driving tumor aggression. Our results suggest that K17 may enhance PDAC aggression by mediating EMT. Hence, novel therapeutic agents targeting K17 may improve clinical care for this biologically distinct patient subgroup.

Bioactive and multifunctional keratin-pullulan based hydrogel membranes facilitate re-epithelization in diabetic model

Hydrogel membrane dressings with multifunctional tunable properties encompassing biocompatibility, anti-bacterial, oxygen permeability, and adequate mechanical strength are highly preferred for wound healing. The present study aimed to develop biopolymer-based hydrogel membranes for the controlled release of therapeutic agent at the wound site. Toward this end we developed Cefotaxime sodium (CTX) loaded keratin (KR)-pullulan (PL) based hydrogel membrane dressings. All membranes show optimized vapor transmission rate (≥1000 g/ m2/day), oxygen permeability >8.2 mg/mL, MTT confirmed good biocompatibility and sufficient tensile strength (17.53 ± 1.9) for being used as a wound dressing. Nonetheless, KR-PL-PVA membranes show controlled CTX release due to enriched hydrophilic moieties which protect the wound from getting infected. In vivo results depict that CTX-KR-PL-PVA membrane group shows a rapid wound closure rate (p < 0.05) with appreciable angiogenesis, accelerated re-epithelization, and excessive collagen deposition at the wound site. These results endorsed that CTX-KR-PL-PVA hydrogel membranes are potential candidates for being used as dressing material in the diabetic wound.

Activation of the C3a anaphylatoxin receptor inhibits keratinocyte proliferation by regulating keratin 6, keratin 16, and keratin 17 in psoriasis.

Emerging evidence suggests that signaling through the C3a anaphylatoxin receptor (C3aR) protects against various inflammation-related diseases. However, the role of C3aR in psoriasis remains unknown. The purpose of this study was to investigate the possible protective role of C3aR in psoriasis and to explore the underlying molecular mechanisms. We initially found that the psoriatic epidermis exhibited significantly decreased C3aR expression. C3aR showed protective roles in mouse models of imiquimod (IMQ)- and interleukin-23-induced psoriasis. Furthermore, increased epidermal thickness and keratin 6 (K6), K16, and K17 expression occurred in the ears and backs of C3aR-/- mice. Pharmacological treatment with a C3aR agonist ameliorated IMQ-induced psoriasiform lesions in mice and decreased the expression of K6, K16, and K17. Additionally, the signal transducer and activator of transcription 3 (STAT3) pathway participated in the protective function of C3aR. More importantly, the expression levels of K6, K16, and K17 in keratinocytes were all restored in HaCaT cells transfected with a C3aR-overexpression plasmid after treating them with colivelin (a STAT3 activator). Our findings demonstrate that C3aR protects against the development of psoriasis and suggest that C3aR confers protection by negatively regulating K6, K16, and K17 expression in a STAT3-dependent manner, thus inhibiting keratinocyte proliferation and helping reverse the pathogenesis of psoriasis.

Molecular characterization of vascular intestinal obstruction using whole-exome sequencing.

BackgroundVascular intestinal obstruction is a rare intestinal disease with a rapid progression, poor prognosis, and high mortality. This study aimed to identify several mutations associated with vascular intestinal obstruction.MethodsWhole-exome sequencing (WES) was performed on the peripheral blood of 9 sporadic patients with acute vascular intestinal obstruction. The mutation genes in each patient and the mutation genes shared by all 9 patients were identified. Next, a functional annotation analysis and a protein-protein interaction (PPI) analysis of the shared mutation genes in the 9 patients were performed. Copy number variations (CNVs) were identified using the open-source software CNV kit.ResultsIn total, all 9 patients shared 112 mutation genes. The Reactome database revealed 2 significantly enriched pathways, the O-linked glycosylation of the mucins (MUCs), and the termination of the O-glycan biosynthesis. MUC5AC was the protein with the highest degree in the PPI network. After searching the TiGER database, the keratin 18 (KRT18), MUC4, and MUC3A genes were found to be significantly more highly expressed in the colon tissues than the other tissues. Additionally, ArfGAP with dual PH domains 1 (ADAP1), cytochrome P450 family 2 subfamily W member 1 (CYP2W1), and transmembrane protein 184A (TMEM184A) were found to be highly expressed in colon tissues. The expression levels of several candidate genes between the vascular intestinal obstruction and normal control patients were measured by quantitative real-time polymerase chain reaction (qRT-PCR).ConclusionsOur study identified multiple mutations in 4 genes (i.e., MUC3A, MUC5AC, MUC16, and KRT18), and the CYP2W1 deletion. Our findings extend understandings of the potential pathological mechanism of vascular intestinal obstruction.

High Keratin-7 Expression in Benign Peri-Tumoral Prostatic Glands Is Predictive of Bone Metastasis Onset and Prostate Cancer-Specific Mortality.

Simple SummaryKeratin-7 overexpression has been associated with poor prognosis in several cancers. To determine its prognostic relevance in prostate cancer, cohorts of patients presenting with localized or advanced tumors were investigated by either immunohistochemistry or immunofluorescence. Keratin-7 immunostaining was absent in localized tumors and rare in advanced tumors. By contrast, it was abundantly detected in basal cells within benign glands surrounding localized tumors. Importantly, high keratin-7 expression in benign peri-tumoral glands was correlated with shorter bone metastasis-free survival and increased risk of cancer-specific mortality. This study establishes keratin-7 expression in localized prostate cancer specimens as a promising biomarker of disease progression.Background: New predictive biomarkers are needed to accurately predict metastasis-free survival (MFS) and cancer-specific survival (CSS) in localized prostate cancer (PC). Keratin-7 (KRT7) overexpression has been associated with poor prognosis in several cancers and is described as a novel prostate progenitor marker in the mouse prostate. Methods: KRT7 expression was evaluated in prostatic cell lines and in human tissue by immunohistochemistry (IHC, on advanced PC, n = 91) and immunofluorescence (IF, on localized PC, n = 285). The KRT7 mean fluorescence intensity (MFI) was quantified in different compartments by digital analysis and correlated to clinical endpoints in the localized PC cohort. Results: KRT7 is expressed in prostatic cell lines and found in the basal and supra-basal compartment from healthy prostatic glands and benign peri-tumoral glands from localized PC. The KRT7 staining is lost in luminal cells from localized tumors and found as an aberrant sporadic staining (2.2%) in advanced PC. In the localized PC cohort, high KRT7 MFI above the 80th percentile in the basal compartment was significantly and independently correlated with MFS and CSS, and with hypertrophic basal cell phenotype. Conclusion: High KRT7 expression in benign glands is an independent biomarker of MFS and CSS, and its expression is lost in tumoral cells. These results require further validation on larger cohorts.

Fibulin-4 Accelerates Amyloid Formation by Binding with a Keratin 5 Peptide Fragment

Keratins are the major amyloid fibril component in localized cutaneous amyloidosis. We analyzed the amyloid components in the skin of patients with localized cutaneous amyloidosis by immunohistochemical staining using antisera against extracellular matrix proteins and keratin 5 (K5). Fibulin-4 and K5 colocalized in the amyloid deposits. Using 14 synthetic peptides, we screened for amyloidogenic sequences in the C-terminal region of K5, including the α-helical rod domain and the tail domain. Two peptides stained with thioflavin T possessed a β-sheet structure and formed amyloid-like fibrils. Among the amyloidogenic peptides, a peptide KT5-6 (YQELMNTKLALDVEIATYRKLLEGE) derived from the α-helical rod domain of K5 specifically bound to fibulin-4. In addition, amyloid formation of KT5-6 was accelerated by fibulin-4. These results suggest that degraded fragments of K5 containing the KT5-6 sequence form amyloid fibrils with fibulin-4. The data further suggest that degraded fragments of K5 and fibulin-4 have the potential to initiate cutaneous amyloidosis.

ΔNp63-Senataxin circuit controls keratinocyte differentiation by promoting the transcriptional termination of epidermal genes

SignificanceΔNp63 is a master regulator of skin homeostasis since it finely controls keratinocyte differentiation and proliferation. Here, we provide cellular and molecular evidence demonstrating the functional role of a ΔNp63 interactor, the R-loop-resolving enzyme Senataxin (SETX), in fine-tuning keratinocyte differentiation. We found that SETX physically binds the p63 DNA-binding motif present in two early epidermal differentiation genes, Keratin 1 (KRT1) and ZNF750, facilitating R-loop removal over their 3' ends and thus allowing efficient transcriptional termination and gene expression. These molecular events translate into the inability of SETX-depleted keratinocytes to undergo the correct epidermal differentiation program. Remarkably, SETX is dysregulated in cutaneous squamous cell carcinoma, suggesting its potential involvement in the pathogenesis of skin disorders.

Expression Level of Keratin 7 in Epithelial Ovarian Cancer and Malignant Metastasis of Benign Epithelial Ovarian Tumors.

It was to investigate the diagnostic value of keratin 7 (KRT7) in malignant metastasis of epithelial ovarian cancer and benign epithelial ovarian tumors. From January 2018 to January 2019, 30 fresh tissues of benign epithelial ovarian tumors, 30 fresh tissues of borderline tumors, 30 fresh tissues of metastatic ovarian were collected in The First Affiliated Hospital of Fujian Medical University, and 30 fresh tissues of normal ovarian tissues were collected as the control group. Federation of gynecology and obstetrics (FIGO) staging criteria: 25 cases of stage I, 26 cases of stage II, 16 cases of stage III, and 23 cases of stage IV. The relative expression of KRT7 was detected by real-time fluorescence quantitative PCR, and the relationship between KRT7 expression and epithelial ovarian cancer grading was analyzed. The results showed that the positive expression rate of KRT7 was 12.1% in normal ovarian tissues, 28.4% in benign epithelial ovarian tumors, 53.5% in borderline tumors, and 24.2% in metastatic ovarian cancer. With the increase of tumor stage malignancy, the relative expression of KRT7 decreased significantly, but there was no significant difference between stage I and stage II, stage III and stage IV (P > 0.05). The difference between stage I and stage III, and stage IV was significant (P < 0.05). Patients with epithelial ovarian cancer had a significant difference compared with the control group (P < 0.05). In summary, compared with the control group, the expression of KRT7 in patients with benign epithelial ovarian tumors and borderline tumors was significantly decreased. The expression level of KRT7 in benign epithelial ovarian tumors was lower than that in borderline tumors. The expression of KRT7 was related to the occurrence, development, and deterioration of ovarian cancer, which provided a basis for targeted therapy of tumors.

Efficacy of Off-Label Therapy for Non-alcoholic Fatty Liver Disease in Improving Non-invasive and Invasive Biomarkers: A Systematic Review and Network Meta-Analysis of Randomized Controlled Trials

ObjectiveTo evaluate the effects of vitamin E, pioglitazone, sodium-glucose cotransporter-2 (SGLT2) inhibitors, and glucagon-like peptide-1 (GLP-1) receptor agonists in patients with non-alcoholic fatty liver disease (NAFLD).DesignA network meta-analysis.Data SourcesPubMed, Embase, Cochrane Library, and Web of Science databases from their inception until September 1, 2021.Eligibility Criteria for Selecting StudiesRandomized controlled trials (RCTs) comparing the effects of four different drugs in patients with NAFLD were included. All superiority, non-inferiority, phase II and III, non-blinded, single-blinded, and double-blinded trials were included. Interventions of interest included vitamin E (α-tocopherol and δ-tocotrienol), pioglitazone, three kinds of GLP-1 receptor agonists (liraglutide, semaglutide, and dulaglutide), four SGLT2 inhibitors (dapagliflozin, empagliflozin, ipragliflozin, and tofogliflozin), and comparisons of these different drugs, and placebos.Main Outcome MeasuresThe outcome measures included changes in non-invasive tests [alanine aminotransferase (ALT), aspartate aminotransferase (AST), gamma-glutamyl transferase (GGT), controlled attenuation parameter (CAP), enhanced liver fibrosis (ELF) score, liver fat content (LFC), and keratin-18 (K-18)] and invasive tests [fibrosis score and resolution of non-alcoholic steatohepatitis (NASH)].ResultsTwenty-seven trials including 3,416 patients were eligible for inclusion in the study. Results refer to vitamin E, pioglitazone, GLP-1 receptor agonists, and SGLT2 inhibitors. First, placebos were used as a reference. δ-Tocotrienol was superior to placebo in decreasing the GGT level. Semaglutide, ipragliflozin, and pioglitazone induced a significantly higher decrease in the ALT level than a placebo. Semaglutide, pioglitazone, and dapagliflozin were superior to placebo in decreasing the AST level. Tofogliflozin and pioglitazone induced a significantly higher decrease in the K-18 level than a placebo. Liraglutide was superior to placebo in decreasing CAP. Liraglutide, pioglitazone, and vitamin E induced a significantly higher increase in resolution of NASH than a placebo. As for pairwise comparisons, semaglutide and pioglitazone were superior to liraglutide in decreasing the ALT level. Semaglutide induced a significantly higher decrease in the ALT level than dulaglutide. Semaglutide was obviously superior to empagliflozin, liraglutide, dulaglutide, and tofogliflozin in decreasing the AST level. Pioglitazone induced a significantly higher decrease in the GGT level than ipragliflozin. δ-Tocotrienol was superior to liraglutide in decreasing the GGT level. Tofogliflozin and pioglitazone induced a significantly higher decrease in the K-18 level than dulaglutide. Pioglitazone was superior to vitamin E in increasing the resolution of NASH. Furthermore, liraglutide treatment had the highest SUCRA ranking in decreasing CAP and ELF scores and increasing the resolution of NASH. Pioglitazone treatment had the highest SUCRA ranking in decreasing LFC and fibrosis scores. Tofogliflozin treatment had the highest SUCRA ranking in decreasing K-18, while dapagliflozin treatment had the highest SUCRA ranking in decreasing the GGT level. Semaglutide treatment had the highest SUCRA ranking in decreasing the levels of ALT and AST.ConclusionThe network meta-analysis provided evidence for the efficacy of vitamin E, pioglitazone, SGLT2 inhibitors, and GLP-1 receptor agonists in treating patients with NAFLD. To find the best guide-level drugs, it is necessary to include more RCTs with these off-label drugs, so that patients and clinicians can make optimal decisions together.Systematic Review Registrationhttps://www.crd.york.ac.uk/prospero, identifier: CRD42021283129.

Generation of three induced pluripotent stem cell lines (UQACi003-A, UQACi004-A, and UQACi006-A) from three patients with KRT5 epidermolysis bullosa simplex mutations

Heterozygous mutations within Keratin 5 (KRT5) are common genetic causes of epidermolysis bullosa simplex (EBS), a skin fragility disorder characterized by blisters, which appear after minor trauma. Using CytoTune®Sendai virus, we generated three human induced pluripotent stem cell (iPSC) lines from three EBS patients carrying respectively the single heterozygous mutations in KRT5, c.449 T > C, c.980 T > C, and c.608 T > C. All lines display normal karyotype, expressed high levels of pluripotent markers, and can differentiate into derivatives of the three germ layers. These iPSCs are helpful for a better understanding of the EBS pathogenesis and developing novel therapeutic approaches.

Distinct Roles of m5C RNA Methyltransferase NSUN2 in Major Gynecologic Cancers.

RNA methylation has recently emerged as an important category of epigenetic modifications, which plays diverse physiopathological roles in various cancers. Recent studies have confirmed the presence of 5-methylcytosine (m5C) modification on mammalian mRNAs, mainly modified by NOP2/Sun RNA methyltransferase family member 2 (NSUN2), but little is known about the underlying functions of m5C. Gynecologic cancers are malignancies starting from women’s reproductive organs. The prevalence of gynecologic cancers leads to a massive economic burden and public health concern. In this study, we investigated the potential biological functions of NSUN2 in common gynecologic cancers including cervical cancer, ovarian cancer, and endometrial cancer. Remarkably, distinct scenarios were found. The levels of NSUN2 did not show alteration in endometrial cancer, and in ovarian cancer, depletion of upregulated NSUN2 did not reduce carcinogenesis in cancer cells, suggesting that the upregulated NSUN2 might be an incidental effect. On the contrary, NSUN2 played a role in tumorigenesis of cervical cancer; depletion of upregulated NSUN2 notably inhibited migration and invasion of cancer cells, and only wild-type but not catalytically inactive NSUN2 rescued these malignant phenotypes of cancer cells. Mechanistically, NSUN2 promoted migration and invasion by leading to m5C methylation on keratin 13 (KRT13) transcripts, and methylated KRT13 transcripts would be recognized and stabilized by an m5C reader, Y-box binding protein 1 (YBX1). Collectively, these results not only displayed the nature of diversity among human malignancies, but also demonstrated a novel NSUN2-dependent m5C-YBX1-KRT13 oncogenic regulatory pathway.

Transient receptor potential vanilloid 1 plays a major role in low temperature–mediated skin barrier dysfunction

Children born in the fall and winter are at increased risk for developing atopic dermatitis and food allergy. Because these seasons are associated with low temperatures, we hypothesized that exposure to low temperatures may compromise keratinocyte differentiation and contribute to skin barrier dysfunction. We examined whether low temperature causes skin barrier dysfunction. Primary human epidermal keratinocytes (HEK) were differentiated in 1.3 mmol CaCl2 media and cultured at different temperatures. The cells were transfected with transient receptor potential cation channel subfamily V member 1 (TRPV1) or STAT3 small interfering RNA (siRNA) to examine the effects of these gene targets in HEK exposed to low temperature. Gene expression of TRPV1, epidermal barrier proteins, and keratinocyte-derived cytokines were evaluated. Organotypic skin equivalents were generated using HEK transfected with control or TRPV1 siRNA and grown at 25°C or 37°C. Transepidermal water loss (TEWL) and levels of epidermal barrier proteins were evaluated. Filaggrin (FLG) and loricrin (LOR) expression, but not keratin (KRT)-1 and KRT-10 expression, was downregulated in HEK incubated at 25°C, while TRPV1 silencing increased intracellular Ca2+ influx (keratinocyte differentiation signal) and enhanced the expression of epidermal differentiation proteins. IL-1β and thymic stromal lymphopoietin induced by low temperature inhibited FLG expression in keratinocytes through the TRPV1/STAT3 pathway. Moreover, low temperature-mediated inhibition of FLG and LOR was recovered, and TEWL was decreased in organotypic skin transfected with TRPV1 siRNA. TRPV1 is critical in low temperature-mediated skin barrier dysfunction. Low temperature exposure induced thymic stromal lymphopoietin, an alarmin implicated in epicutaneous allergen sensitization.

Analysis of transcript-wide profile regulated by microsatellite instability of colorectal cancer.

BackgroundMicrosatellite instability-high (MSI-H) is a form of genomic instability present in 15% of colorectal cancer (CRC) cases. Several differential gene analyses have been conducted on CRC; however, none have specifically explored the differentially expressed genes in MSI-H CRC. Research on the different gene expressions between MSI-H CRC and microsatellite stable (MSS) CRC, and their different patterns of metastasis will provide invaluable insights for diagnosis, prognosis, and treatment.MethodsIn this study, the differential expression of 46,602 genes were analyzed across 613 different tissue samples from The Cancer Genome Atlas (TCGA)-colon adenocarcinoma (COAD) and TCGA-rectum adenocarcinoma (READ) as part of a gene association analysis. R package TCGAbiolinks (version 2.18.0) was used to download the data set, and DESeq2 (version 1.30.1) was used for the differential gene analysis. The resulting genes were then analyzed for shared pathways with R package clusterProfiler (version 3.0.4).ResultsA total of 237 significantly differentially expressed genes (Padj<0.05) were found between MSI-H and MSS CRC. Differentially expressed genes include insulin like growth factor 2 (IGF2) and fibroblast growth factor 3 (FGF3), and the enriched pathways mostly involve hearing, digestive regulation, and neurogenesis.463 differentially expressed genes were found between metastatic and non-metastatic CRC. Notably differentially expressed genes in metastatic CRC include DEAD-box helicase 53 (DDX53) and adiponectin, C1Q and collagen domain containing (ADIPOQ), and enriched pathways include the immune system, cell adhesion, and cell signaling. For MSI-H CRC, a total of 34 genes were significantly differently expressed between metastatic and non-metastatic CRC. These include notum, palmitoleoyl-protein carboxylesterase (NOTUM), serpin family B member 2 (SERPINB2), and several keratin (KRT) genes, and the pathway analysis showed the major enrichment of the hormonal and secretion and regulation pathways. Of the differentially expressed genes in metastatic CRC, 25 were immunity related and include fatty acid binding protein 4 (FABP4), and the pathway analysis showed the enrichment of humoral immunity and lymphocyte regulation.ConclusionsOf the biologically plausible differentially expressed genes, the most notable were NOTUM, KRT6A, KRT14, SERPINB2, and serum amyloid A1 (SAA1). NOTUM, KRT6A, and KRT14 are active in the Wnt pathway. All five are also involved in various inflammation pathways.

Autophagosome-lysosome fusion is facilitated by plectin-stabilized actin and keratin 8 during macroautophagic process.

Autophagy is a lysosome-mediated degradative process that removes damaged proteins and organelles, during which autophagosome-lysosome fusion is a key step of the autophagic flux. Based on our observation that intermediate cytofilament keratin 8 (KRT8) enhances autophagic clearance in cells under oxidative stress condition, we investigated whether KRT8 supports the cytoplasmic architectural networks to facilitate the vesicular fusion entailing trafficking onto filamentous tracks. We found that KRT8 interacts with actin filaments via the cytolinker, plectin (PLEC) during trafficking of autophagosome. When PLEC was knocked down or KRT8 structure was collapsed by phosphorylation, autophagosome-lysosome fusion was attenuated. Inhibition of actin polymerization resulted in accumulation of autophagosomes owing to a decrease in autophagosome and lysosome fusion. Furthermore, myosin motor protein was found to be responsible for vesicular trafficking along the actin filaments to entail autolysosome formation. Thus, the autophagosome-lysosome fusion is aided by PLEC-stabilized actin filaments as well as intermediate cytofilament KRT8 that supports the structural integrity of actin filaments during macroautophagic process under oxidative stress condition.

KRT13 promotes stemness and drives metastasis in breast cancer through a plakoglobin/c-Myc signaling pathway

BackgroundKeratins (KRTs) are intermediate filament proteins that interact with multiple regulatory proteins to initiate signaling cascades. Keratin 13 (KRT13) plays an important role in breast cancer progression and metastasis. The objective of this study is to elucidate the mechanism by which KRT13 promotes breast cancer growth and metastasis.MethodsThe function and mechanisms of KRT13 in breast cancer progression and metastasis were assessed by overexpression and knockdown followed by examination of altered behaviors in breast cancer cells and in xenograft tumor formation in mouse mammary fat pad. Human breast cancer specimens were examined by immunohistochemistry and multiplexed quantum dot labeling analysis to correlate KRT13 expression to breast cancer progression and metastasis.ResultsKRT13-overexpressing MCF7 cells displayed increased proliferation, invasion, migration and in vivo tumor growth and metastasis to bone and lung. Conversely, KRT13 knockdown inhibited the aggressive behaviors of HCC1954 cells. At the molecular level, KRT13 directly interacted with plakoglobin (PG, γ-catenin) to form complexes with desmoplakin (DSP). This complex interfered with PG expression and nuclear translocation and abrogated PG-mediated suppression of c-Myc expression, while the KRT13/PG/c-Myc signaling pathway increased epithelial to mesenchymal transition and stem cell-like phenotype. KRT13 expression in 58 human breast cancer tissues was up-regulated especially at the invasive front and in metastatic specimens (12/18) (p < 0.05). KRT13 up-regulation in primary breast cancer was associated with decreased overall patient survival.ConclusionsThis study reveals that KRT13 promotes breast cancer cell growth and metastasis via a plakoglobin/c-Myc pathway. Our findings reveal a potential novel pathway for therapeutic targeting of breast cancer progression and metastasis.

Identification of Biomarkers Associated with Cancerous Change in Oral Leukoplakia Based on Integrated Transcriptome Analysis.

Objective Oral leukoplakia (OLK) is the most common precancerous lesion in the oral cavity. This study aimed to explore key biomarkers for monitoring OLK for early diagnosis of oral squamous cell carcinoma (OSCC) and screen small-molecule drugs for the prevention of OSCC. Method The Gene Expression Omnibus (GEO) database was explored to extract two microarray datasets, namely, GSE85195 and GSE25099. The data of the normal group, OLK group, and OSCC group were analyzed by weighted gene coexpression network analysis (WGCNA) to identify the most significant gene module and differentially expressed genes (DEGs). The intersection genes were extracted as the key genes of OLK carcinogenesis. Subsequently, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways were analyzed in the module. Connectivity Map and molecular docking were used to screen small-molecule drugs. The diagnostic values of four key genes were identified and verified in the GSE26549 dataset. Results WGCNA obtained the red module (r = −0.91, p < 0.05) with the strongest correlation with cancerous phenotype. GO enrichment analysis showed 60 pathways, including 28 biological processes, 11 cell components, and 21 molecular functions, and KEGG enrichment analysis showed 4 pathways (p < 0.05). In the differential expression analysis, there was no intersection between the upregulated genes and the red module genes. However, the intersection of the downregulated genes and the red module genes yielded 4 key genes: dopachrome tautomerase (DCT), keratin 3 (KRT3), keratin 76 (KRT76), and FAM3 metabolic regulation signal molecule B (FAM3B). The area under the curve of the diagnostic model constructed by these four genes was 0.963 (CI = 0.913–1.000). The sensitivity was 0.933, and the specificity was 0.923. The diagnostic model was successfully verified in GSE26549 (AUC = 0.745, CI = 0.638–0.851). Compared with the diagnostic models of the previous studies, the diagnostic efficiency of this model was the highest. The small-molecule drugs, selumetinib and benidipine, were selected according to the gene expression profile and showed binding activity when docking with the above molecules. Conclusions This study provides new targets and drugs for OLK. These targets could be used as the key diagnostic molecules for long-term follow-up of OLK. The small-molecule drugs selumetinib and benidipine could be used for the prevention and treatment of OSCC.

Association of Keratin 8 Level in Aqueous Humor With Outcomes of Intravitreal Ranibizumab Treatment for Neovascular Age-Related Macular Degeneration.

PurposeTo investigate keratin 8 (KRT8) level in the aqueous humor (AH) of patients with neovascular age-related macular degeneration (nAMD) and elucidate its association with intravitreal ranibizumab (IVR) treatment outcomes.MethodsThis prospective study involved 58 eyes of treatment-naïve nAMD patients treated with three IVR doses monthly and whose AH samples were collected at baseline and two months after the initial treatment. KRT8 level was determined using the enzyme-linked immunosorbent assay and compared with that of the control group, which comprised patients who underwent cataract surgery during the same period. The nAMD-affected eyes were classified into responder (dry) and poor responder (persistent fluid) groups, according to optical coherence tomography (OCT) findings at month three. Additionally, associations between the KRT8 level and IVR treatment outcomes were analyzed.ResultsThe baseline KRT8 level was significantly higher in the AMD group than in the control group. In the AMD group, responders demonstrated significant differences between the KRT8 level at the baseline and month two, whereas poor responders exhibited no significant change. Regression analysis revealed that a higher KRT8 level at month two was significantly associated with persistent fluid upon OCT at months three and six.ConclusionsMonitoring aqueous KRT8 level may facilitate early determination of the therapeutic effects of IVR in nAMD patients and reflect the conditions of retinal pigment epithelium during the disease course.Translational RelevanceMonitoring aqueous KRT8 may aid early determination of therapeutic effects of IVR in neovascular AMD patients and reflect the health conditions of retinal pigment epithelium.