Apoptosis and keratin intermediate filaments

KRT10 plays an important role in the release of viral genome from endosomes during H9N2 subtype AIV replication in HeLa cells

The infection and replication of avian influenza virus (AIV) in host cells is a complex biological process that involves the transport of viral genes through the host cell's transport systems. Actin, microtubules and vimentin are known to facilitate transport of endosomes to the perinuclear region, but the biological role of Keratin, another intermediate filament, in viral transport during AIV replication is not well understood. In this study, the viral NS2 protein was used as the target protein to identify the potential interacting proteins following GST-Pulldown method and protein mass spectrometry. It was discovered that Keratin10 interacted with NS2. Subsequently, it was found AIV infection did not affect the gene level or protein level of keratin10 in HeLa cells, but when Keratin10 was knocked down, the expressions of viral NP mRNA and protein were reduced, and the generation of offspring virus also was also decreased. Furthermore, in early viral infection, Keratin10 could aggregate and co-localize with NP proteins, suggesting that Keratin10 might be connected to early viral transport. Additionally, it was demonstrated that Keratin10 co-localized with Lamp1 and that AIV particles were trapped in late endosomes/Lysosomes after Keratin10 was knocked down. Finally, it was discovered that the knocking down Keratin10 in HeLa cells led to an increase in the acidic pH of endosomes and lysosomes, which prevented AIV from undergoing fusion and uncoating, and then inhibited the process of the viral infection. Overall, the results suggested that Keratin10 might play the critical role in the release of vRNPs from LEs/Ls and can affect the generation of offspring virus. The study provides the novel insights into the role of Keratin10 in the process of AIV infection and transmission, which may have implications for developing new strategies to against AIV infections.

Mesenchymal-epithelial transition in lymph node metastases of oral squamous cell carcinoma is accompanied by ZEB1 expression

BACKGROUND

Oral squamous cell carcinoma (OSCC), an HPV-negative head and neck cancer, frequently metastasizes to the regional lymph nodes but only occasionally beyond. Initial phases of metastasis are associated with an epithelial-mesenchymal transition (EMT), while the consolidation phase is associated with mesenchymal-epithelial transition (MET). This dynamic is referred to as epithelial-mesenchymal plasticity (EMP). While it is known that EMP is essential for cancer cell invasion and metastatic spread, less is known about the heterogeneity of EMP states and even less about the heterogeneity between primary and metastatic lesions.

METHODS

To assess both the heterogeneity of EMP states in OSCC cells and their effects on stromal cells, we performed single-cell RNA sequencing (scRNAseq) of 5 primary tumors, 9 matching metastatic and 5 tumor-free lymph nodes and re-analyzed publicly available scRNAseq data of 9 additional primary tumors. For examining the cell type composition, we performed bulk transcriptome sequencing. Protein expression of selected genes were confirmed by immunohistochemistry.

RESULTS

From the 23 OSCC lesions, the single cell transcriptomes of a total of 7263 carcinoma cells were available for in-depth analyses. We initially focused on one lesion to avoid confounding inter-patient heterogeneity and identified OSCC cells expressing genes characteristic of different epithelial and partial EMT stages. RNA velocity and the increase in inferred copy number variations indicated a progressive trajectory towards epithelial differentiation in this metastatic lesion, i.e., cells likely underwent MET. Extension to all samples revealed a less stringent but essentially similar pattern. Interestingly, MET cells show increased activity of the EMT-activator ZEB1. Immunohistochemistry confirmed that ZEB1 was co-expressed with the epithelial marker cornifin B in individual tumor cells. The lack of E-cadherin mRNA expression suggests this is a partial MET. Within the tumor microenvironment we found immunomodulating fibroblasts that were maintained in primary and metastatic OSCC.

CONCLUSIONS

This study reveals that EMP enables different partial EMT and epithelial phenotypes of OSCC cells, which are endowed with capabilities essential for the different stages of the metastatic process, including maintenance of cellular integrity. During MET, ZEB1 appears to be functionally active, indicating a more complex role of ZEB1 than mere induction of EMT.

The apoptotic effects of soybean agglutinin were induced through three different signal pathways by down-regulating cytoskeleton proteins in IPEC-J2 cells

Soybean agglutinin (SBA) is a main anti-nutritional factor in soybean. SBA exhibits its anti-nutritional functions by binding to intestinal epithelial cells. Keratin8 (KRT8), Keratin18 (KRT18) and Actin (ACTA) are the representative SBA-specific binding proteins. Such cytoskeletal proteins act a crucial role in different cell activities. However, limited reports reveal what the signal transduction pathway of apoptosis caused by SBA when binding to KRT8, KRT18 and ACTA. We aimed to evaluate the effects of SBA on cell apoptosis and the expression of the cytoskeletal protein (KRT8, KRT18 and ACTA), reveal the roles of these cytoskeletal proteins or their combinations on SBA-induced cell apoptosis in IPEC-J2 cell line, evaluate the influences of SBA on the mitochondria, endoplasmic reticulum stress and death receptor-mediated apoptosis signal pathway and to show the roles of KRT8, KRT18 and ACTA in different apoptosis signal pathways induced by SBA. The results showed that SBA induced the IPEC-J2 cell apoptosis and decreased the mRNA expression of KRT8, KRT18 and ACTA (p < 0.05). The degree of effect of three cytoskeleton proteins on cell apoptosis was ACTA > KRT8 > KRT18. The roles of these three cytoskeletal proteins on IPEC-J2 apoptotic rates had a certain accumulation effect. SBA up-regulated mitochondrial fission variant protein (FIS1) and fusion protein (Mfn2) promoted CytC and AIF in mitochondria to enter the cytoplasm, activated caspase-9 and caspase-3, damaged or declined mitochondrial function and reduced ATP synthesis (p < 0.05). Also, SBA up-regulated the expression of GRP78, XBP-1, eIF2α, p-eIF2α and CHOP (p < 0.05), down-regulated the expression level of ASK1 protein (p < 0.05). SBA led to the recruitment of FADD to the cytoplasmic membrane and increased the expression of FasL, resulting in caspase-8 processing. SBA up-regulated the expression level of Bax protein and decreased cytosolic Bcl-2 and Bid (p < 0.05). In addition, there was a significant negative correlation between the gene expression of cytoskeleton proteins and apoptosis, as well as the expression of key proteins of apoptosis-related signal transduction pathways. In conclusion, SBA induced the activation of the mitochondria, endoplasmic reticulum stress and the death receptor-mediated apoptosis signal pathway and the crosstalk between them. The effect of SBA on these three pathways was mainly exhibited via down-regulation of the mRNA expression of the three cytoskeletal expressions. This study elucidates the molecular mechanism and signaling pathway of SBA that lead to apoptosis from the perspective of cell biology and molecular biology and provides a new perspective on the toxicity mechanism of other food-derived anti-nutrients, medical gastrointestinal health and related cancer treatment.

Keratin-mediated hair growth and its underlying biological mechanism

Here we show that intradermal injection of keratin promotes hair growth in mice, which results from extracellular interaction of keratin with hair forming cells. Extracellular application of keratin induces condensation of dermal papilla cells and the generation of a P-cadherin-expressing cell population (hair germ) from outer root sheath cells via keratin-mediated microenvironmental changes. Exogenous keratin-mediated hair growth is reflected by the finding that keratin exposure from transforming growth factor beta 2 (TGFβ2)-induced apoptotic outer root sheath cells appears to be critical for dermal papilla cell condensation and P-cadherin-expressing hair germ formation. Immunodepletion or downregulation of keratin released from or expressed in TGFβ2-induced apoptotic outer root sheath cells negatively influences dermal papilla cell condensation and hair germ formation. Our pilot study provides an evidence on initiating hair regeneration and insight into the biological function of keratin exposed from apoptotic epithelial cells in tissue regeneration and development.

Keratin Biomaterials in Skin Wound Healing, an Old Player in Modern Medicine: A Mini Review

Impaired wound healing is a major medical problem. To solve it, researchers around the world have turned their attention to the use of tissue-engineered products to aid in skin regeneration in case of acute and chronic wounds. One of the primary goals of tissue engineering and regenerative medicine is to develop a matrix or scaffold system that mimics the structure and function of native tissue. Keratin biomaterials derived from wool, hair, and bristle have been the subjects of active research in the context of tissue regeneration for over a decade. Keratin derivatives, which can be either soluble or insoluble, are utilized as wound dressings since keratins are dynamically up-regulated and needed in skin wound healing. Tissue biocompatibility, biodegradability, mechanical durability, and natural abundance are only a few of the keratin biomaterials' properties, making them excellent wound dressing materials to treat acute and chronic wounds. Several experimental and pre-clinical studies described the beneficial effects of the keratin-based wound dressing in faster wound healing. This review focuses exclusively on the biomedical application of a different type of keratin biomaterials as a wound dressing in pre-clinical and clinical conditions.

Extracellular and Intracellular Skeletons: How Do They Involve in Apoptosis

Apoptosis plays a key role in removing abnormal or senescent cells, maintaining the overall health of the tissue, and coordinating individual development. Recently, it has been discovered that the intracellular cytoskeleton plays a role in the apoptotic process. In addition, the regulatory role of extracellular matrix (ECM) fibrous proteins, which can be considered as the extracellular skeleton, in the process of apoptosis is rarely summarized. In this review, we collect the latest knowledge about how fibrous proteins inside and outside cells regulate apoptosis. We describe how ECM fibrous proteins participate in the regulation of death receptor and mitochondrial pathways through various signaling cascades mediated by integrins. We then explore the molecular mechanisms by which intracellular intermediate filaments regulate cell apoptosis by regulating death receptors on the cell membrane surface. Similarly, we report on novel supporting functions of microtubules in the execution phase of apoptosis and discuss their formation mechanisms. Finally, we discuss that the polypeptide fragments formed by caspase degradation of ECM fibrous proteins and intracellular intermediate filament act as local regulatory signals to play different regulatory roles in apoptosis.

Assembly and recognition of keratins: A structural perspective

Keratins are one of the major components of cytoskeletal network and assemble into fibrous structures named intermediate filaments (IFs), which are important for maintaining the mechanical properties of cells and tissues. Over the past decades, evidence has shown that the functions of keratins go beyond providing mechanical support for cells, they interact with multiple cellular components and are widely involved in the pathways of cell proliferation, differentiation, motility and death. However, the structural details of keratins and IFs are largely missing and many questions remain regarding the mechanisms of keratin assembly and recognition. Here we briefly review the current structural models and assembly of keratins as well as the interactions of keratins with the binding partners, which may provide a structural view for understanding the mechanisms of keratins in the biological activities and the related diseases.

Role of Apoptosis in Wound Healing and Apoptosis Alterations in Microgravity

Functioning as the outermost self-renewing protective layer of the human organism, skin protects against a multitude of harmful biological and physical stimuli. Consisting of ectodermal, mesenchymal, and neural crest-derived cell lineages, tissue homeostasis, and signal transduction are finely tuned through the interplay of various pathways. A health problem of astronauts in space is skin deterioration. Until today, wound healing has not been considered as a severe health concern for crew members. This can change with deep space exploration missions and commercial spaceflights together with space tourism. Albeit the molecular process of wound healing is not fully elucidated yet, there have been established significant conceptual gains and new scientific methods. Apoptosis, e.g., programmed cell death, enables orchestrated development and cell removal in wounded or infected tissue. Experimental designs utilizing microgravity allow new insights into the role of apoptosis in wound healing. Furthermore, impaired wound healing in unloading conditions would depict a significant challenge in human-crewed exploration space missions. In this review, we provide an overview of alterations in the behavior of cutaneous cell lineages under microgravity in regard to the impact of apoptosis in wound healing. We discuss the current knowledge about wound healing in space and simulated microgravity with respect to apoptosis and available therapeutic strategies.

Prostaglandin F2 Alpha Triggers the Disruption of Cell Adhesion with Cytokeratin and Vimentin in Bovine Luteal Theca Cells

Simple Summary

Luteolysis is an important event in the control of the corpus luteum function in bovines. However, some aspects of the luteolytic mechanism remain unclear. We evaluated changes in cell adhesion in luteal cells during regression of corpus luteum. Bovine luteal theca cells (LTCs) were treated in vitro with Prostaglandin F2 alpha (PGF2α). Cytokeratin, vimentin and desmoplakin proteins in LTCs were disrupted by PGF2α, affecting cell adhesion. These results suggest that PGF2α plays an important function in cell adhesion during the regression of corpus luteum.

Abstract

Intermediate filaments (IFs) maintain cell–cell adhesions and are involved in diverse cellular processes such as cytokinesis, cell migration and the maintenance of cell structure. In this study, we investigated the influence of prostaglandin F2 alpha (PGF2α) on cytokeratin and vimentin IFs, Rho-associated protein kinase (ROCK), and cell-cell adhesion in bovine luteal theca cells (LTCs). The luteal cells were isolated from bovine corpus luteum (CL), and the LTCs were treated with 0, 0.01, 0.1 and 1.0 mM PGF2α. Cytokeratin, vimentin and desmoplakin proteins were disrupted and the ROCK protein was significantly increased in PGF2α-treated LTCs. In addition, cell–cell adhesion was significantly (p < 0.05) decreased in the PGF2α-induced LTCs compared to control group (0 mM PGF2α). In conclusion, PGF2α affected the adhesion of cell to cell via disruption of desmoplakin, cytokeratin and vimentin, additionally increasing ROCK in bovine LTCs. These results may provide a better understanding of the mechanism of bovine CL regression.

Molecular portrait of squamous cell carcinoma of the bovine horn evaluated by high-throughput targeted exome sequencing: a preliminary report

Background

Squamous Cell Carcinoma of horn, also known as horn cancer, is a prevailing type of cancer in cattles especially Bos indicus. It is one of the most prevalent disease in Indian bullocks often resulting in death and huge economic losses to farmers. Here, we have reported the use of targeted exome sequencing to identify variants present in horn cancer affected horn mucosa tissue and blood of the same animal to identify some of the prevalent markers of horn cancer.

Results

We have observed higher number of variants present in tissue as compared to blood as well as among cancer samples compared to samples from normal animals. Eighty six and 1437 cancer-specific variants were identified among the predicted variants in blood and tissue samples, respectively. Total 25 missense variants were observed distributed over 18 genes. KRT8 gene coding for Keratin8, one of the key constituents of horn, displayed 5 missense variants. Additionally, three other genes involved in apoptosis pathway and two genes involved in antigen presentation and processing also contained variants.

Conclusions

Several genes involved in various apoptotic pathways were found to contain non-synonymous mutations. Keratin8 coding for Keratin, a chief constituent of horn was observed to have the highest number of mutations. In all, we present a preliminary report of mutations observed in horn cancer.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12917-020-02683-y.

The adaptive immune response to porous regenerated keratin as a bone graft substitute in an ovine model

Reconstituted keratin is a novel bone graft material when prepared as a rigid scaffold. Understanding the immunogenicity of this material is important to determine whether this substance is a viable surgical option. Previous studies have shown no innate immune system activation in response to reconstituted keratin implants. To examine antibody-mediated immune responses to reconstituted keratin implants, bone and blood samples were taken from twelve sheep with surgically created tibial defects containing such implants. RT-PCR was used to detect mRNA of the inflammatory marker SOCS 3 in local bony tissue, and a novel immunohistochemistry assay developed to detect antikeratin antibodies in serum. Two animals were sacrificed per time-point at weeks 1, 2, 4, 6, 8 and 12. Time points for serum analysis included baseline (pre-surgery) and all other time points; mRNA analysis examined samples from all time points. No upregulation in antikeratin antibodies or SOCS 3 mRNA was observed at any time point, indicating that reconstituted keratin implants do not trigger an adaptive immune response in vivo in an ovine model. These findings provide the platform for further development of keratin implants in other mammalian models to define its immunogenic profile and safety.

Anticancer Strategy Targeting Cell Death Regulators: Switching the Mechanism of Anticancer Floxuridine-Induced Cell Death from Necrosis to Apoptosis

Cell death can be broadly characterized as either necrosis or apoptosis, depending on the morphological and biochemical features of the cell itself. We have previously reported that the treatment of mouse mammary carcinoma FM3A cells with the anticancer drug floxuridine (FUdR) induces necrosis in the original clone F28-7 but apoptosis in the variant F28-7-A. We have identified regulators, including heat shock protein 90, lamin-B1, cytokeratin-19, and activating transcription factor 3, of cell death mechanisms by using comprehensive gene and protein expression analyses and a phenotype-screening approach. We also observed that the individual inhibition or knockdown of the identified regulators in F28-7 results in a shift from necrotic to apoptotic morphology. Furthermore, we investigated microRNA (miRNA, miR) expression profiles in sister cell strains F28-7 and F28-7-A using miRNA microarray analyses. We found that several unique miRNAs, miR-351-5p and miR-743a-3p, were expressed at higher levels in F28-7-A than in F28-7. Higher expression of these miRNAs in F28-7 induced by transfecting miR mimics resulted in a switch in the mode of cell death from necrosis to apoptosis. Our findings suggest that the identified cell death regulators may play key roles in the decision of cell death mechanism: necrosis or apoptosis.

Dicer- and Bulge Stem Cell-Dependent MicroRNAs During Induced Anagen Hair Follicle Development

MicroRNAs (miRNAs) are a major class of conserved non-coding RNAs that have a wide range of functions during development and disease. Biogenesis of canonical miRNAs depend on the cytoplasmic processing of pre-miRNAs to mature miRNAs by the Dicer endoribonuclease. Once mature miRNAs are generated, the miRNA-induced silencing complex (miRISC), or miRISC, incorporates one strand of miRNAs as a template for recognizing complementary target messenger RNAs (mRNAs) to dictate post-transcriptional gene expression. Besides regulating miRNA biogenesis, Dicer is also part of miRISC to assist in activation of the complex. Dicer associates with other regulatory miRISC co-factors such as trans-activation responsive RNA-binding protein 2 (Tarbp2) to regulate miRNA-based RNA interference. Although the functional role of miRNAs within epidermal keratinocytes has been extensively studied within embryonic mouse skin, its contribution to the normal function of hair follicle bulge stem cells (BSCs) during post-natal hair follicle development is unclear. With this question in mind, we sought to ascertain whether Dicer-Tarpb2 plays a functional role within BSCs during induced anagen development by utilizing conditional knockout mouse models. Our findings suggest that Dicer, but not Tarbp2, functions within BSCs to regulate induced anagen (growth phase) development of post-natal hair follicles. These findings strengthen our understanding of miRNA-dependency within hair follicle cells during induced anagen development.

FMRP ribonucleoprotein complexes and RNA homeostasis

The Fragile Mental Retardation 1 gene (FMR1), at Xq27.3, encodes the fragile mental retardation protein (FMRP), and displays in its 5'-untranslated region a series of polymorphic CGG triplet repeats that may undergo dynamic mutation. Fragile X syndrome (FXS) is the leading cause of inherited intellectual disability among men, and is most frequently due to FMR1 full mutation and consequent transcription repression. FMR1 premutations may associate with at least two other clinical conditions, named fragile X-associated primary ovarian insufficiency (FXPOI) and tremor and ataxia syndrome (FXTAS). While FXPOI and FXTAS appear to be mediated by FMR1 mRNA accumulation, relative reduction of FMRP, and triplet repeat translation, FXS is due to the lack of the RNA-binding protein FMRP. Besides its function as mRNA translation repressor in neuronal and stem/progenitor cells, RNA editing roles have been assigned to FMRP. In this review, we provide a brief description of FMR1 transcribed microsatellite and associated clinical disorders, and discuss FMRP molecular roles in ribonucleoprotein complex assembly and trafficking, as well as aspects of RNA homeostasis affected in FXS cells.

Significance of Cytokeratin-1 Single-Nucleotide Polymorphism and Protein Level in Susceptibility to Vocal Leukoplakia and Laryngeal Squamous Cell Carcinoma

OBJECTIVE

To investigate the association between the cytokeratin (CK)-1 single-nucleotide polymorphism (SNP), the protein level of CK-1 and the risk of vocal leukoplakia and laryngeal squamous cell carcinoma (LSCC).

METHODS

In this case-control study, 155 patients with vocal leukoplakia, 323 patients with LSCC, and 266 healthy controls were genotyped for the CK-1 (SNP RS14024) gene using pyrosequencing. The protein expression level of CK-1 was analyzed in vocal leukoplakia, LSCC, and vocal polyp patients by immunohistochemistry (IHC).

RESULTS

Of the CK-1 RS14024 polymorphism, the heterozygote AG and homozygote GG genotype exhibited a significantly increased risk of LSCC (AG: OR = 2.16, p = 0.014; GG: OR = 2.15, p = 0.018) compared to normal controls. A higher protein expression level of CK-1 was detected in patients with LSCC compared to vocal leukoplakia and polyps (both p < 0.001), and a significant increasing trend of CK-1 protein expression level from mild-moderate dysplasia to moderate-severe dysplasia in vocal leukoplakia patients was also observed (p = 0.006).

CONCLUSIONS

This study demonstrates that the CK-1 SNP and high protein expression levels are associated with vocal leukoplakia and LSCC and promote the transformation from vocal leukoplakia to LSCC in a Chinese Han population.

Expression of new genes in vertebrate tooth development and p63 signaling

BACKGROUND

p63 is an evolutionarily ancient transcription factor essential to vertebrate tooth development. Our recent gene expression screen comparing wild-type and "toothless" p63^-/- mouse embryos implicated in tooth development several new genes that we hypothesized act downstream of p63 in dental epithelium, where p63 is also expressed.

RESULTS

Via in situ hybridization and immunohistochemistry, we probed mouse embryos (embryonic days 10.5-14.5) and spotted gar fish embryos (14 days postfertilization) for these newly linked genes, Cbln1, Cldn23, Fermt1, Krt15, Pltp and Prss8, which were expressed in mouse and gar dental epithelium. Loss of p63 altered expression levels but not domains. Expression was comparable between murine upper and lower tooth organs, implying conserved gene functions in maxillary and mandibular dentitions. Our meta-analysis of gene expression databases supported that these genes act within a p63-driven gene regulatory network important to tooth development in mammals and more evolutionary ancient vertebrates (fish, amphibians).

CONCLUSIONS

Cbln1, Cldn23, Fermt1, Krt15, Pltp, and Prss8 were expressed in mouse and fish dental epithelium at placode, bud, and/or cap stages. We theorize that these genes participate in cell-cell adhesion, cell polarity, and extracellular matrix signaling to support dental epithelium integrity, folding, and epithelial-mesenchymal cross talk during tooth development.

Development of high-performance two-dimensional gel electrophoresis for human hair shaft proteome

The primary components of human hair shaft—keratin and keratin-associated proteins (KAPs), together with their cross-linked networks—are the underlying reason for its rigid structure. It is therefore requisite to overcome the obstacle of hair insolubility and establish a reliable protocol for the proteome analysis of this accessible specimen. The present study employed an alkaline-based method for the efficient isolation of hair proteins and subsequently examined them using gel-based proteomics. The introduction of two proteomic protocols, namely the conventional and modified protocol, have resulted in the detection of more than 400 protein spots on the two-dimensional gel electrophoresis (2DE). When compared, the modified protocol is deemed to improve overall reproducibility, whilst offering a quick overview of the total protein distribution of hair. The development of this high-performance protocol is hoped to provide a new approach for hair analysis, which could possibly lead to the discovery of biomarkers for hair in health and diseases in the future.

Shadow Cell Differentiation: A Comparative Analysis of Modes of Cell Death with Apoptosis and Epidermal/Trichilemmal Keratinization

Shadow cells are characterized by an eosinophilic cytoplasm and a ghost-like nuclear contour; the cell shape is preserved, in spite of nuclear disappearance. Shadow cell nests (SCNs) are frequently observed in pilomatricoma (PMX), where the transitional cells immediately adjacent to SCNs often have a crescent-shaped nucleus showing fragmentation similar to that of apoptotic bodies. They show nuclear accumulation of beta-catenin and DNA double strand breaks (as revealed by in situ 3′-tailing reaction or immunohistochemistry for single-stranded DNA [ssDNA]), while they are negative for cleaved caspase-3 or cleaved lamin A, suggesting that shadow cell differentiation (SCD) is a caspase-independent programmed cell death. SCD can be differentiated from epidermal keratinization (EK) and trichilemmal keratinization (TK) based on the expression pattern of beta-catenin, ssDNA, and caspase-14/CD138. SCD is observed not only in PMX, but also sometimes in basal cell carcinomas, gonadal teratomas, and various extra-cutaneous carcinomas. In particular, SCNs are found in 24$ of endometrial adenoacanthoma and are derived from squamoid morules. This establishes a link between basaloid cells in PMX and squamoid morules in endometrial adenoacanthomas as common precursors of shadow cells. Overall, it is suggested that SCD is different from, but partly similar to, apoptosis and that SCD and EK/TK should be differentiated from the standpoint of cell death/differentiation.

The Hair Follicle: An Underutilized Source of Cells and Materials for Regenerative Medicine

The hair follicle is one of only two structures within the adult body that selectively degenerates and regenerates, making it an intriguing organ to study and use for regenerative medicine. Hair follicles have been shown to influence wound healing, angiogenesis, neurogenesis, and harbor distinct populations of stem cells; this has led to cells from the follicle being used in clinical trials for tendinosis and chronic ulcers. In addition, keratin produced by the follicle in the form of a hair fiber provides an abundant source of biomaterials for regenerative medicine. In this review, we provide an overview of the structure of a hair follicle, explain the role of the follicle in regulating the microenvironment of skin and the impact on wound healing, explore individual cell types of interest for regenerative medicine, and cover several applications of keratin-based biomaterials.

Allele-specific recognition by LILRB3 and LILRA6 of a cytokeratin 8-associated ligand on necrotic glandular epithelial cells

The LILRs are a family of receptors that regulate the activities of myelomonocytic cells. We found that specific allelic variants of two related members of the LILR family, LILRB3 and LILRA6, interact with a ligand exposed on necrotic glandular epithelial cells. The extracellular domains of LILRB3 and LILRA6 are very similar and their genes are highly polymorphic. A commonly occurring allele, LILRB3*12, displayed particularly strong binding of these necrotic cells and further screening of the products of LILRB3 alleles identified motifs that correlated with binding. Immunoprecipitation of the ligand from epithelial cell lysates using recombinant LILRB3*12, identified cytokeratins 8, 18 and 19. Purified proteins obtained from epithelial cell lysates, using anti-cytokeratin 8 antibodies, were able to activate LILRB3*12 reporter cells. Knock-down of cytokeratin 8 in epithelial cells abrogated expression of the LILRB3 ligand, while staining with recombinant LILRB3*12 showed co-localisation with cytokeratin 8 and 18 in permeabilised breast cancer cells. Necrosis is a common feature of tumours. The finding of a necrosis-associated ligand for these two receptors raises the possibility of a novel interaction that alters immune responses within the tumour microenvironment. Since LILRB3 and LILRA6 genes are highly polymorphic the interaction may influence an individual's immune response to tumours.

PADI4 rs2240337 G>A polymorphism is associated with susceptibility of esophageal squamous cell carcinoma in a Chinese population

Background

Esophageal cancer (EC) remains one of the major causes of cancer incidence and mortality worldwide. Genetic factors, such as single nucleotide polymorphisms (SNPs), may contribute to the carcinogenesis of EC.

Methods

We conducted a hospital based case-control study to evaluate the genetic susceptibility of SNPs on the development of EC. A total of 629 esophageal squamous cell carcinoma (ESCC) cases and 686 controls were enrolled for this study. Seven PADI4 SNPs were determined by ligation detection reaction method.

Results

Our findings suggested that the PADI4 rs2240337 GA/AA variants were significantly associated with decreased risk of ESCC. Haplotype PADI4 A_rs2477137C_rs1886302G_rs11203366G_rs16825533G_rs2240337A_rs1635564A_rs1635562 and C_rs2477137T_rs1886302G_rs11203366A_rs1635564G_rs2240337C_rs1635564T_rs1635562 polymorphism was correlated with decreased susceptibility to ESCC, while C_rs2477137T_rs1886302A_rs11203366A_rs1635564G_rs2240337A_rs1635564A_rs1635562 was correlated with increased susceptibility of ESCC. Stratification analyses demonstrated that smoking significantly increased ESCC risk in PADI4 rs11203366 AG/AA, rs1886302 CC/CT, rs1635562 AT, rs1635564 CA and rs2477137 AC genotype. Alcohol drinking increased ESCC risk in PADI4 rs11203366 AG, rs1635562 AT, rs1635564 CA, rs2477137 AC, rs1886302 CT genotype. In younger cohort (<63 years), rs11203366 AA genotype was associated with increased risk of ESCC. PADI4 rs1886302 CC variant was associated with ESCC susceptibility in female cohort.

Conclusions

Our study suggested that PADI4 rs2240337 G>A polymorphism may be correlated with individual susceptibility to ESCC. PADI4 rs11203366, rs1886302, rs1635562, rs1635564 and rs2477137 polymorphisms were implicated with altered susceptibility of ESCC based on sex, age, smoking status and alcohol consumption. However, larger studies among different ethnic populations and further experiments using genetically mutated cells or animals are warranted to verify our conclusion.

Biomarkers of systemic lupus erythematosus identified using mass spectrometry-based proteomics: a systematic review

Advances in mass spectrometry technologies have created new opportunities for discovering novel protein biomarkers in systemic lupus erythematosus (SLE). We performed a systematic review of published reports on proteomic biomarkers identified in SLE patients using mass spectrometry‐based proteomics and highlight their potential disease association and clinical utility. Two electronic databases, MEDLINE and EMBASE, were systematically searched up to July 2015. The methodological quality of studies included in the review was performed according to Preferred Reporting Items for Systematic Reviews and Meta‐analyses guidelines. Twenty‐five studies were included in the review, identifying 241 SLE candidate proteomic biomarkers related to various aspects of the disease including disease diagnosis and activity or pinpointing specific organ involvement. Furthermore, 13 of the 25 studies validated their results for a selected number of biomarkers in an independent cohort, resulting in the validation of 28 candidate biomarkers. It is noteworthy that 11 candidate biomarkers were identified in more than one study. A significant number of potential proteomic biomarkers that are related to a number of aspects of SLE have been identified using mass spectrometry proteomic approaches. However, further studies are required to assess the utility of these biomarkers in routine clinical practice.

Tocotrienol and cancer metastasis

Tumor metastasis involves some of the most complex and dynamic processes in cancer, often leading to poor quality of life and inevitable death. The search for therapeutic compounds and treatment strategies to prevent and/or manage metastasis is the ultimate challenge to fight cancer. In the past two decades, research focus on vitamin E has had a shift from saturated tocopherols to unsaturated tocotrienols (T3). Despite sharing structural similarities with tocopherols, T3 strive to gain scientific prominence due to their anti-cancer effects. Recent studies have shed some light on the anti-metastatic properties of T3. In this review, the roles of T3 in each step of the metastatic process are discussed. During the invasion process, signaling pathways that regulate the extracellular matrix and tumor cell motility have been reported to be modulated by T3. Although studies on T3 and tumor cell migration are fairly limited, they were shown to play a vital role in the suppression of angiogenesis. Furthermore, the anti-inflammatory effect of T3 could be highly promising in the regulation of tumor microenvironment, which is crucial in supporting tumor growth in distant organs.

Molecular manipulation of keratin 8/18 intermediate filaments: modulators of FAS-mediated death signaling in human ovarian granulosa tumor cells

Background

Granulosa cell tumors (GCT) are a rare ovarian neoplasm but prognosis is poor following recurrence. Keratin intermediate filaments expressed in these tumors are a diagnostic marker, yet paradoxically, may also constitute a target for therapeutic intervention. In the current study, we evaluated keratin 8/18 (K8/18) filament expression as a mechanism of resistance to apoptosis in GCT, specifically focusing on regulation of the cell surface death receptor, Fas (FAS).

Methods

The GCT cell line, KGN, was transiently transfected with siRNA to KRT8 and KRT18 to reduce K8/18 filament expression. Expression of K8/18, FAS, and apoptotic proteins (PARP, cleaved PARP) were evaluated by fluorescence microscopy, flow cytometric analysis, and immunoblotting, respectively. The incidence of FAS-mediated apoptosis in KGN cells was measured by caspase 3/7 activity. All experiments were performed independently three to six times, using a fresh aliquot of KGN cells for each experiment. Quantitative data were analyzed by one- or two-way analysis of variance (ANOVA), followed by a Tukey’s post-test for multiple comparisons; differences among means were considered statistically significant at P < 0.05.

Results

Control cultures of KGN cells exhibited abundant K8/18 filament expression (~90 % of cells), and minimal expression of FAS (<25 % of cells). These cells were resistant to FAS-activating antibody (FasAb)-induced apoptosis, as determined by detection of cleaved PARP and measurement of caspase 3/7 activity. Conversely, siRNA-mediated knock-down of K8/18 filament expression enhanced FAS expression (> 70 % of cells) and facilitated FasAb-induced apoptosis, evident by increased caspase 3/7 activity (P < 0.05). Additional experiments revealed that inhibition of protein synthesis, but not MEK1/2 or PI3K signaling, also prompted FasAb-induced apoptosis.

Conclusions

The results demonstrated that K8/18 filaments provide resistance to apoptosis in GCT by impairing FAS expression. The abundance of keratin filaments in these cells and their role in apoptotic resistance provides a greater mechanistic understanding of ovarian tumorgenicity, specifically GCT, as well as a clinically-relevant target for potential therapeutic intervention.

Sulforaphene inhibits hepatocellular carcinoma through repressing keratin 8 and activating anoikis

Sulforaphene can induce anoikis in hepatoma cells though down-regulation of keratin 8 activating the Fas death receptor pathway.

Tumor necrosis factor-α confers cardioprotection through ectopic expression of keratins K8 and K18

Tumor necrosis factor-α (TNF-α), one of the major stress-induced proinflammatory cytokines, is upregulated in the heart after tissue injury, and its sustained expression can contribute to the development of heart failure. Whether TNF-α also exerts cytoprotective effects in heart failure is not known. Here we provide evidence for a cardioprotective function of TNF-α in a genetic heart failure model, desmin-deficient mice. The cardioprotective effects of TNF-α are a consequence of nuclear factor-κB (NF-κB)-mediated ectopic expression in cardiomyocytes of keratin 8 (K8) and keratin 18 (K18), two epithelial-specific intermediate filament proteins. In cardiomyocytes, K8 and K18 (K8/K18) formed an alternative cytoskeletal network that localized mainly at intercalated discs (IDs) and conferred cardioprotection by maintaining normal ID structure and mitochondrial integrity and function. Ectopic induction of K8/K18 expression in cardiomyocytes also occurred in other genetic and experimental models of heart failure. Loss of the K8/K18 network resulted in a maladaptive cardiac phenotype following transverse aortic constriction. In human failing myocardium, where TNF-α expression is upregulated, K8/K18 were also ectopically expressed and localized primarily at IDs, which did not contain detectable amounts of desmin. Thus, TNF-α- and NF-κB-mediated formation of an alternative, stress-induced intermediate filament cytoskeleton has cardioprotective function in mice and potentially in humans.

Quantitative interactome analysis reveals a chemoresistant edgotype

Chemoresistance is a common mode of therapy failure for many cancers. Tumours develop resistance to chemotherapeutics through a variety of mechanisms, with proteins serving pivotal roles. Changes in protein conformations and interactions affect the cellular response to environmental conditions contributing to the development of new phenotypes. The ability to understand how protein interaction networks adapt to yield new function or alter phenotype is limited by the inability to determine structural and protein interaction changes on a proteomic scale. Here, chemical crosslinking and mass spectrometry were employed to quantify changes in protein structures and interactions in multidrug-resistant human carcinoma cells. Quantitative analysis of the largest crosslinking-derived, protein interaction network comprising 1,391 crosslinked peptides allows for ‘edgotype' analysis in a cell model of chemoresistance. We detect consistent changes to protein interactions and structures, including those involving cytokeratins, topoisomerase-2-alpha, and post-translationally modified histones, which correlate with a chemoresistant phenotype.

Changes in protein–protein interactions result in changes to cellular phenotype. Here the authors use crosslinking mass spectrometry to derive a quantitative protein interaction network in drug-sensitive and -resistant HeLa cells, and uncover a chemoresistant ‘edgotype'.

Significance of Serum Cytokeratin-18 in Prediction of Hepatocellular Carcinoma in Chronic Hepatitis C Infected Egyptian Patients

BACKGROUND

Hepatitis C virus is one of the most common etiologic agents of chronic liver diseases, including liver cirrhosis and hepatocellular carcinoma in which there is continuous inflammation and regeneration of hepatocytes. Cytokeratin-18 (CK18) has been suggested to play an important role in tumorigenesis of epithelial cancers.

AIM

Estimation of CK18 serum levels in patients with chronic viral hepatitis C (CHCV) and hepatocellular carcinoma (HCC) and find the relationship between their levels, the severity of the disease and the development of HCC.

METHODS

We measured serum levels of CK18 in 60 Egyptian patients (30 with CHCV & 30 with HCC) and 30 healthy controls.

RESULTS

Patients with HCC had highly significant increased CK18 levels compared with CHCV patients, healthy controls. Cytokeratin-18 among the three classes of Child-Pugh classification show highly significant gradual increase from child A to C. Furthermore, In HCC there were positive correlations between CK18 and with RBCs, ESR, and AFP.

CONCLUSION

CK18 is a sensitive indicator of the severity of liver disease. Patients with CHCV infection can be followed up by measurement of its serum level which can predict the development of HCC. The combination of AFP and CK18 increased the sensitivity of detection for HCC.

Exploiting the cytoskeletal filaments of neoplastic cells to potentiate a novel therapeutic approach

Although cytoskeletal-directed agents have been a mainstay in chemotherapeutic protocols due to their ability to readily interfere with the rapid mitotic progression of neoplastic cells, they are all microtubule-based drugs, and there has yet to be any microfilament- or intermediate filament-directed agents approved for clinical use. There are many inherent differences between the cytoskeletal networks of malignant and normal cells, providing an ideal target to attain preferential damage. Further, numerous microfilament-directed agents, and an intermediate filament-directed agent of particular interest (withaferin A) have demonstrated in vitro and in vivo efficacy, suggesting that cytoskeletal filaments may be exploited to supplement chemotherapeutic approaches currently used in the clinical setting. Therefore, this review is intended to expose academics and clinicians to the tremendous variety of cytoskeletal filament-directed agents that are currently available for further chemotherapeutic evaluation. The mechanisms by which microfilament directed- and intermediate filament-directed agents damage malignant cells are discussed in detail in order to establish how the drugs can be used in combination with each other, or with currently approved chemotherapeutic agents to generate a substantial synergistic attack, potentially establishing a new paradigm of chemotherapeutic agents.

Piwil2 inhibits keratin 8 degradation through promoting p38-induced phosphorylation to resist Fas-mediated apoptosis

The piwi-like 2 (piwil2) gene is widely expressed in tumors and protects cells from apoptosis induced by a variety of stress stimuli. However, the role of Piwil2 in Fas-mediated apoptosis remains unknown. Here, we present evidence that Piwil2 inhibits Fas-mediated apoptosis. By a bacterial two-hybrid screening, we identify a new Piwil2-interacting partner, keratin 8 (K8), a major intermediate filament protein protecting the cell from Fas-mediated apoptosis. Our results show that Piwil2 binds to K8 and p38 through its PIWI domain and forms a Piwil2/K8/P38 triple protein-protein complex. Thus, Piwil2 increases the phosphorylation level of K8 Ser-73 and then inhibits ubiquitin-mediated degradation of K8. As a result, the knockdown of Piwil2 increases the Fas protein level at the membrane. In addition to our previous finding that Piwil2 inhibits the expression of p53 through the Src/STAT3 pathway, here we demonstrate that Piwil2 represses p53 phosphorylation through p38. Our present study indicates that Piwil2 plays a role in Fas-mediated apoptosis for the first time and also can affect p53 phosphorylation in tumor cells, revealing a novel mechanism of Piwil2 in apoptosis, and supports that Piwil2 plays an active role in tumorigenesis.

EGR1 decreases the malignancy of human non-small cell lung carcinoma by regulating KRT18 expression

Early growth response 1 (EGR1) is a multifunctional transcription factor; Positive and negative functions of EGR1 in various tumors rely on the integrated functions of various genes it regulates. In this study, we observed the role of EGR1 in non-small-cell lung carcinoma (NSCLC) and identified genes that influence cell fate and tumor development. Various assays showed that EGR1 arrested cell mobility, inhibited migration, and induced apoptosis. Microarray analysis revealed that 100 genes, including CDKN1C, CDC27 and PRKDC, changed their mRNA expressions with the increase of EGR1 and contributed to intervention of tumor progression. Bioinformatics analysis and promoter analysis indicated that an EGR1 binding site was situated in the promoter of KRT18 (also named CK18) and KRT18 could assist in inhibition of NSCLC development. The expression level of EGR1 and KRT18 in NSCLC clinical cases was investigated by immunohistochemistry, in which the protein expression of KRT18 was found to be significantly associated with EGR1 and lymph node metastasis. The results collectively confirm that EGR1 functions as a tumor suppressor in NSCLC. This study is the first to report KRT18 expression is directly regulated by EGR1, and contributes to decrease malignancy of NSCLC.

Current and emerging biomarkers of cell death in human disease

Cell death is a critical biological process, serving many important functions within multicellular organisms. Aberrations in cell death can contribute to the pathology of human diseases. Significant progress made in the research area enormously speeds up our understanding of the biochemical and molecular mechanisms of cell death. According to the distinct morphological and biochemical characteristics, cell death can be triggered by extrinsic or intrinsic apoptosis, regulated necrosis, autophagic cell death, and mitotic catastrophe. Nevertheless, the realization that all of these efforts seek to pursue an effective treatment and cure for the disease has spurred a significant interest in the development of promising biomarkers of cell death to early diagnose disease and accurately predict disease progression and outcome. In this review, we summarize recent knowledge about cell death, survey current and emerging biomarkers of cell death, and discuss the relationship with human diseases.

Group B streptococcal infection of the choriodecidua induces dysfunction of the cytokeratin network in amniotic epithelium: a pathway to membrane weakening

Early events leading to intrauterine infection remain poorly defined, but may hold the key to preventing preterm delivery. To determine molecular pathways within fetal membranes (chorioamnion) associated with early choriodecidual infection that may progress to preterm premature rupture of membranes (PPROM), we examined the effects of a Group B Streptococcus (GBS) choriodecidual infection on chorioamnion in a nonhuman primate model. Ten chronically catheterized pregnant monkeys (Macaca nemestrina) at 118–125 days gestation (term = 172 days) received choriodecidual inoculation of either GBS (n = 5) or saline (n = 5). Cesarean section was performed in the first week after GBS or saline inoculation. RNA extracted from chorioamnion (inoculation site) was profiled by microarray. Single gene, Gene Set, and Ingenuity Pathway Analysis results were validated using qRT-PCR (chorioamnion), Luminex (amniotic fluid, AF), immunohistochemistry, and transmission electron microscopy (TEM). Despite uterine quiescence in most cases, significant elevations of AF cytokines (TNF-α, IL-8, IL-1β, IL-6) were detected in GBS versus controls (p<0.05). Choriodecidual infection resolved by the time of cesarean section in 3 of 5 cases and GBS was undetectable by culture and PCR in the AF. A total of 331 genes were differentially expressed (>2-fold change, p<0.05). Remarkably, GBS exposure was associated with significantly downregulated expression of multiple cytokeratin (CK) and other cytoskeletal genes critical for maintenance of tissue tensile strength. Immunofluorescence revealed highly significant changes in the CK network within amniocytes with dense CK aggregates and retraction from the cell periphery (all p = 0.006). In human pregnancies affected by PPROM, there was further evidence of CK network retraction with significantly shorter amniocyte foot processes (p = 0.002). These results suggest early choriodecidual infection results in decreased cellular membrane integrity and tensile strength via dysfunction of CK networks. Downregulation of CK expression and perturbations in the amniotic epithelial cell intermediate filament network occur after GBS choriodecidual infection, which may contribute to PPROM.

Group B Streptococcus (GBS) is one cause of preterm birth, stillbirth, and fetal brain injury. GBS is present in the vagina and is thought to ascend into the uterus of some women where it can cause placental inflammation and preterm birth. Understanding the earliest events in the placenta that lead to preterm birth is elusive in humans, because the placenta cannot be studied until after birth. Here, we use a nonhuman primate model to show that an early GBS infection can damage the structural support of the fetal membranes, specifically the cytokeratin network in the epithelium of the amnion (one part of the membranes). Next, we obtained human placentas to show that this cytokeratin network was also damaged in human patients that had preterm premature rupture of the membranes, a major cause of preterm birth. Our work is important in understanding why fetal membranes may rupture prematurely, which may lead to early interventions to prevent membrane damage after placental infection and preterm birth.

Intermediate filament: structure, function, and applications in cytology

Intermediate filament (IF) constitutes an important cytoskeletal component in nearly all the vertebrate cells. IFs are present both in the cytoplasm and in the nucleus. They play an important role in providing mechanical strength of the cell and tissue, growth and regeneration, cell survival and apoptosis, and finally cell migration. IFs are also expressed differentially in different body tissues. Therefore, judicious use of IF may provide the diagnosis and confirmation of different malignancies. This is particularly helpful in the diagnosis of metastatic malignant tumor from an unknown primary. Expression of IFs particularly cytokeratin and vimentin is also related to prognosis of tumors. In this review, we have discussed the basic structure, dynamics, distribution of IF in cells, and its role in diagnosis of cytology. Possible prognostic roles of IF are also discussed.

Keratin 8 is involved in hepatitis B virus replication

Hepatitis B virus (HBV) infection can result in fatal liver diseases, including cirrhosis or liver failure, and its replication and pathogenesis depend on the critical interplay between viral and host factors. This study investigated HBV replication-related host proteins and the effect of candidate proteins on HBV replication. Isobaric tags for relative and absolute quantitation (iTRAQ) were used to measure HBV replication-related proteins in HepG2 cells and HepG2.2.15 cells. KRT8 was up-regulated in HepG2.2.15 cells but not in HepG2 cells, and KRT8 was overexpressed in an HBV-infected patient's liver tissue. This result suggested that KRT8 is involved in HBV replication. To further clarify the relationship between KRT8 and HBV replication, KRT8 gene expression was inhibited by siRNA. The silencing of KRT8 mildly suppressed HBV replication. Moreover, overexpressed KRT8 significantly increased HBV replication, and the inhibition of HBV DNA did not suppress KRT8 expression. Thus, the host protein KRT8 is involved in the replication of HBV DNA, and it dramatically enhances HBV replication.

Caspase-cleaved fragments of cytokeratin-18 as a marker of inflammatory activity in chronic hepatitis B virus infection

BACKGROUND

The differential diagnosis between inactive carrier and active hepatitis is important in patients with chronic hepatitis B (CHB) virus infection. Serum cytokeratin (CK)-18 fragments (M30-antigen) are proposed as biomarkers of apoptosis.

OBJECTIVES

We investigated whether serum M30-antigen levels might help to characterize the various phases of CHB and predict the state of significant inflammation in patients with CHB.

STUDY DESIGN

A total of 339 CHB patients who underwent liver biopsy, were included. Serum M30-antigen levels were compared between inactive carriers (n=21), patients with HBeAg-negative hepatitis (n=95), HBeAg-positive hepatitis (n=141) and liver cirrhosis (n=82).

RESULTS

Serum M30-antigen levels were correlated significantly not only with AST (r=0.544, p<0.001) and ALT (r=0.315, p<0.001) and but also inflammatory grading score on liver biopsy (r=0.240, p<0.001). Serum M30-antigen level in HBeAg-negative CHB was significantly higher than that of inactive HBV carrier (399.78 U/L vs 148.90 U/L, p<0.001). Multivariate analysis showed that AST (p<0.001), albumin (p=0.009) and M30-antigen (p=0.020) were the independent predictors of significant inflammation. Combined serum M30-antigen level (>344 U/L) and AST (>78 IU/L) measurement provided the most accurate identification of significant inflammation, showing 38.2% sensitivity, 96.1% specificity, 91.0% positive predictive value and 56.1% negative predictive value.

CONCLUSIONS

Serum M30-antigen can be a predictive marker for distinguishing between inactive carrier and HBeAg-negative CHB. Serum M30 levels are associated with the presence of significant inflammation, especially in patients with normal or minimally elevated ALT in CHB patients.

Serum m 30 levels reflects ulcerative colitis activity

BACKGROUND

Apoptosis plays a role in epithelial and mucosal injury, which is 1 of the mechanisms in the pathogenesis of ulcerative colitis. Apoptotic cells increase as a result of injured mucosa in ulcerative colitis and serum M 30 levels increase in epithelial cell apoptosis. In this study, we aimed to evaluate the relation between M 30 serum levels and ulcerative colitis activity.

METHODS

Eighty patients with ulcerative colitis and 40 healthy controls were enrolled into the study. The patient group consisted of 31 extensive colitis, 30 left-sided colitis, and 19 proctitis. The activity of ulcerative colitis was determined with clinical and endoscopic findings. Serum M 30 levels, acute phase reactants, and biochemical tests were analyzed in all subjects.

RESULTS

Serum M 30 levels in patients with active ulcerative colitis were significantly higher when compared with the healthy controls (165.6 ± 60.6 and 129.6 ± 37.4; P = 0.003). Serum M 30 levels in active left-sided colitis patients was significantly higher when compared with patients in remission phase (180.6 ± 58.5, 141.5 ± 35.4; P = 0.044). When we exclude patients with ulcerative proctitis, M 30 levels in active ulcerative colitis patients were significantly higher than that the patients in remission phase (174.0 ± 63.5, 135.0 ± 29.9; P = 0.017).

CONCLUSIONS

We found that M 30 levels increase in patients with active ulcerative colitis. Our findings support the role of apoptosis demonstrated by serum M 30 levels in the pathogenesis of active ulcerative colitis.

Parkin induces upregulation of 40S ribosomal protein SA and posttranslational modification of cytokeratins 8 and 18 in human cervical cancer cells

Parkin was originally identified as a protein associated with Parkinson's disease. Recently, numerous research studies have suggested that parkin acts as a tumor suppressor. In accordance with these studies, we previously reported that overexpression of parkin in HeLa cells induced growth inhibition. To elucidate possible mechanisms by which parkin may inhibit cell growth, HeLa cells were infected with adenoviruses expressing either the parkin gene or adenovirus alone for 72 h and a total proteomic analysis was performed using 2-D gel electrophoresis followed by LC-MS/MS. We identified three proteins whose expression changed between the two groups: the 40S ribosomal protein SA (RPSA) was downregulated in parkin virus-infected cells, and cytokeratins 8 and 18 exhibited an acid shift in pI value without a change in molecular weight, suggesting that these proteins became phosphorylated in parkin virus-infected cells. The changes in these three proteins were first observed at 60 h postinfection and were most dramatic at 72 h postinfection. Because upregulation of RPSA and dephosphorylation of cytokeratins 8/18 have been linked with tumor progression, these data suggest that parkin may inhibit cell growth, at least in part, by decreasing RPSA expression and inducing phosphorylation of cytokeratin 8/18.

Depolymerization of cytokeratin intermediate filaments facilitates intracellular infection of HeLa cells by Bartonella henselae

Bartonella henselae is capable of invading epithelial and endothelial cells by modulating the function of actin-dependent cytoskeleton proteins. Although understanding of the pathogenesis has been increased by the development of an in vitro infection model involving endothelial cells, little is known about the mechanism of interaction between B. henselae and epithelial cells. This study aims to identify the binding candidates of B. henselae in epithelial cells and explores their effect on B. henselae infection. Pull-down assays and mass spectrometry analysis confirmed that some of the binding proteins (keratin 14, keratin 6, and F-actin) are cytoskeleton associated. B. henselae infection significantly induces the expression of the cytokeratin genes. Chemical disruption of the keratin network by using ethylene glycol tetraacetic acid promotes the intracellular persistence of B. henselae in HeLa cells. However, cytochalasin B and phalloidin treatment inhibits B. henselae invasion. Immunofluorescent staining demonstrates that B. henselae infection induces an F-actin-dependent rearrangement of the cytoskeleton. However, we demonstrated via immunofluorescent staining and whole-mount cell electron microscopy that keratin intermediate filaments are depolymerized by B. henselae. The results indicate that B. henselae achieves an intracellular persistence in epithelial cells through the depolymerization of cytokeratin intermediate filaments that are protective against B. henselae invasion.

Understanding the role of keratins 8 and 18 in neoplastic potential of breast cancer derived cell lines

Background

Breast cancer is a complex disease which cannot be defined merely by clinical parameters like lymph node involvement and histological grade, or by routinely used biomarkers like estrogen receptor (ER), progesterone receptor (PGR) and epidermal growth factor receptor 2 (HER2) in diagnosis and prognosis. Breast cancer originates from the epithelial cells. Keratins (K) are cytoplasmic intermediate filament proteins of epithelial cells and changes in the expression pattern of keratins have been seen during malignant transformation in the breast. Expression of the K8/18 pair is seen in the luminal cells of the breast epithelium, and its role in prognostication of breast cancer is not well understood.

Methodology/Principal Findings

In this study, we have modulated K8 expression to understand the role of the K8/18 pair in three different breast epithelium derived cell lines: non-transformed MCF10A, transformed but poorly invasive MDA MB 468 and highly invasive MDA MB 435. The up-regulation of K8 in the invasive MDA MB 435 cell line resulted in a significant decrease in proliferation, motility, in-vitro invasion, tumor volume and lung metastasis. The down-regulation of K8 in MDA MB 468 resulted in a significant increase in transformation potential, motility and invasion in-vitro, while MCF10A did not show any changes in cell transformation assays.

Conclusions/Significance

These results indicate the role of K8/18 in modulating invasion in breast cancer -its presence correlating with less invasive phenotype and absence correlating with highly invasive, dedifferentiated phenotype. These data may have important implications for prognostication of breast cancer.

Understanding the role of keratins 8 and 18 in neoplastic potential of breast cancer derived cell lines

BACKGROUND

Breast cancer is a complex disease which cannot be defined merely by clinical parameters like lymph node involvement and histological grade, or by routinely used biomarkers like estrogen receptor (ER), progesterone receptor (PGR) and epidermal growth factor receptor 2 (HER2) in diagnosis and prognosis. Breast cancer originates from the epithelial cells. Keratins (K) are cytoplasmic intermediate filament proteins of epithelial cells and changes in the expression pattern of keratins have been seen during malignant transformation in the breast. Expression of the K8/18 pair is seen in the luminal cells of the breast epithelium, and its role in prognostication of breast cancer is not well understood.

METHODOLOGY/PRINCIPAL FINDINGS

In this study, we have modulated K8 expression to understand the role of the K8/18 pair in three different breast epithelium derived cell lines: non-transformed MCF10A, transformed but poorly invasive MDA MB 468 and highly invasive MDA MB 435. The up-regulation of K8 in the invasive MDA MB 435 cell line resulted in a significant decrease in proliferation, motility, in-vitro invasion, tumor volume and lung metastasis. The down-regulation of K8 in MDA MB 468 resulted in a significant increase in transformation potential, motility and invasion in-vitro, while MCF10A did not show any changes in cell transformation assays.

CONCLUSIONS/SIGNIFICANCE

These results indicate the role of K8/18 in modulating invasion in breast cancer -its presence correlating with less invasive phenotype and absence correlating with highly invasive, dedifferentiated phenotype. These data may have important implications for prognostication of breast cancer.

Cytoskeleton keratin regulation of FasR signaling through modulation of actin/ezrin interplay at lipid rafts in hepatocytes

FasR stimulation by Fas ligand leads to rapid formation of FasR microaggregates, which become signaling protein oligomerization transduction structures (SPOTS), through interactions with actin and ezrin, a structural step that triggers death-inducing signaling complex formation, in association with procaspase-8 activation. In some cells, designated as type I, caspase 8 directly activates effector caspases, whereas in others, known as type II, the caspase-mediated death signaling is amplified through mitochondria. Keratins are the intermediate filament (IF) proteins of epithelial cells, expressed as pairs in a lineage/differentiation manner. Hepatocyte IFs are made solely of keratins 8/18 (K8/K18), the hallmark of all simple epithelia. We have shown recently that in comparison to type II wild-type (WT) mouse hepatocytes, the absence of K8/K18 IFs in K8-null hepatocytes leads to more efficient FasR-mediated apoptosis, in link with a type II/type I-like switch in FasR-death signaling. Here, we demonstrate that the apoptotic process occurring in type I-like K8-null hepatocytes is associated with accelerated SPOTS elaboration at surface membrane, along with manifestation of FasR cap formation and internalization. In addition, the lipid raft organization is altered in K8-null hepatocytes. While lipid raft inhibition impairs SPOTS formation in both WT and K8-null hepatocytes, the absence of K8/K18 IFs in the latter sensitizes SPOTS to actin de-polymerization, and perturbs ezrin compartmentalization. Overall, the results indicate that the K8/K18 IF loss in hepatocytes alters the initial FasR activation steps through perturbation of ezrin/actin interplay and lipid raft organization, which leads to a type II/type I switch in FasR-death signaling.

Detecting phenotype-specific interactions between biological processes from microarray data and annotations

High throughput technologies enable researchers to measure expression levels on a genomic scale. However, the correct and efficient biological interpretation of such voluminous data remains a challenging problem. Many tools have been developed for the analysis of GO terms that are over- or under-represented in a list of differentially expressed genes. However, a previously unexplored aspect is the identification of changes in the way various biological processes interact in a given condition with respect to a reference. Here, we present a novel approach that aims at identifying such interactions between biological processes that are significantly different in a given phenotype with respect to normal. The proposed technique uses vector-space representation, SVD-based dimensionality reduction, differential weighting, and bootstrapping to asses the significance of the interactions under the multiple and complex dependencies expected between the biological processes. We illustrate our approach on two real data sets involving breast and lung cancer. More than 88 percent of the interactions found by our approach were deemed to be correct by an extensive manual review of literature. An interesting subset of such interactions is discussed in detail and shown to have the potential to open new avenues for research in lung and breast cancer.

Diagnostic utility of cytokeratin 17 immunostaining in morpheaform basal cell carcinoma and for facilitating the detection of tumor cells at the surgical margins

BACKGROUND

The morpheaform subtype of basal cell carcinoma (BCC) often presents a diagnostic histological challenge, and its true margin may be difficult to determine with accuracy. This tumor may also be difficult to distinguish from other adnexal neoplasms having a benign clinical course. Previous work has shown that cytokeratin 17 (CK17 or K17) expression is high in BCC.

OBJECTIVE

To confirm the expression of K17 across the subtypes of superficial, nodular and morpheaform BCC variants and to compare K17 expression in each of these subtypes of BCC with that in two other adnexal neoplasms.

METHODS

Tissue specimens from each tumor category were randomly collected, immunolabeled, and scored for K17 expression according to intensity and extent of immunostaining.

RESULTS

Our results indicate that K17 is a useful marker in the identification and outlining of BCC. Moreover, in morpheaform BCC, K17 immunostaining clearly detected individual tumor cells well away from the dermal tumor strands that otherwise seemed nonmalignant according to hematoxylin and eosin staining alone. In addition, the expression of K17 in morpheaform BCC is capable (100% of specimens; p < .001) of distinguishing this tumor from desmoplastic trichoepithelioma.

CONCLUSION

We propose that K17 immunostaining could improve the diagnostic and surgical management of these tumors.