Identification and cloning of a new calmodulin-like protein from human epidermis

Single-Cell RNA Profiling of Ocular Adnexal Sebaceous Carcinoma Reveals a Complex Tumor Microenvironment and Identifies New Biomarkers

PURPOSE

Ocular adnexal sebaceous carcinoma (OaSC) is an aggressive malignancy that often necessitates orbital exenteration. Its tumor composition and transcriptional profile remain largely unknown, which poses a significant barrier to medical advances. Here, we report the first in-depth transcriptomic analysis of OaSC at the single-cell resolution and discern mechanisms underlying cancer progression for the discovery of potential globe-sparing immunotherapies, targeted therapies, and biomarkers to guide clinical management.

DESIGN

Laboratory investigation with a retrospective observational case series.

METHODS

Single-cell RNA sequencing was performed on six patient specimens: three primary tumors, two tumors with pagetoid spread, and a normal tarsus sample. Cellular components were identified via gene signatures. Molecular pathways underlying tumorigenesis and pagetoid spread were discerned via gene ontology analysis of the differentially expressed genes between specimens. CALML5 immunohistochemistry was performed on an archival cohort of OaSC, squamous cell carcinoma, ocular surface squamous neoplasia (OSSN), and basal cell carcinoma cases.

RESULTS

Analysis of 29,219 cells from OaSC specimens revealed tumor, immune, and stromal cells. Tumor-infiltrating immune cells include a diversity of cell types, including exhausted T-cell populations. In primary OaSC tumors, mitotic nuclear division and oxidative phosphorylation pathways are upregulated, while lipid biosynthesis and metabolism pathways are downregulated. Epithelial tissue migration pathways are upregulated in tumor cells undergoing pagetoid spread. Single-cell RNA sequencing analyses also revealed that CALML5 is upregulated in OaSC tumor cells. Diffuse nuclear and cytoplasmic CALML5 staining was present in 28 of 28 (100%) OaSC cases. Diffuse nuclear and membranous CALML5 staining was present in 5 of 25 (20%) squamous cell carcinoma and OSSN cases, while diffuse nuclear staining was present in 1 of 12 (8%) basal cell carcinoma cases.

CONCLUSIONS

This study reveals a complex OaSC tumor microenvironment and confirms that the CALML5 immunohistochemical stain is a sensitive diagnostic marker.

Chondroitin/dermatan sulphate proteoglycan, desmosealin, showing affinity to desmosomes

Objective

Desmosomes are the most prominent interkeratinocyte junctions. The correct barrier function of stratified epithelia such as epidermis depends on their expression. During epidermal differentiation, the molecular composition of desmosomes evolves and so do their physical and chemical properties. Desquamation of corneocytes at the surface of the stratum corneum depends on an orderly degradation of desmosomes by endogenous enzymes. This process may be regulated by glycosylated molecules. We focused on the detection and characterization of potentially implicated players bearing ‘sugar’ characteristics.

Methods

Using an original monoclonal antibody and biochemical methods, we partially characterized a proteoglycan of the exclusively chondroitin/dermatan sulphate type, secreted into the interkeratinocyte spaces, that is incorporated into the extracellular parts of desmosomes in quantities proportional to the degree of cell differentiation, as visualized with immuno-electron microscopy.

Results

This antigen, that we named desmosealin, displays biochemical and immunocytochemical characteristics that clearly differentiate it from known desmosomal elements. Unlike so far described epidermal proteoglycans, which belong to the heparan sulphate family, desmosealin displays chondroitin/dermatan sulphate glycosaminoglycan chains. It can be detected within the extracellular ‘cores’ of desmosomes in the upper viable epidermal layers and in corneodesmosomes from the lowermost part of the stratum corneum.

Conclusion

Extensive integration of proteoglycans into the extracellular parts of desmosomes at the late stages of keratinocyte maturation is likely of functional importance. Given its biochemical profile, its pattern of expression in the epidermis and its desmosomal localization, desmosealin may emerge as a key element in the regulation of desmosome processing, epidermal cohesion and formation of a functional epidermal barrier.

CALML5 is a novel diagnostic marker for differentiating thymic squamous cell carcinoma from type B3 thymoma

BACKGROUND

Thymic squamous cell carcinoma and type B3 thymoma are primary neoplasms of the anterior mediastinum that are sometimes difficult to differentiate from one another histologically. However, only a few immunohistochemical markers are available for the differential diagnosis. The purpose of this study was to discover a novel marker for differentiating between thymic squamous cell carcinoma and type B3 thymoma.

METHODS

We used histological samples of thymic carcinomas (n = 26) and type B3 thymomas (n = 38) which were resected between 1986 and 2017. To search for candidates of differential markers, gene expression levels were evaluated in samples using promoter analysis by cap analysis of gene expression (CAGE) sequencing.

RESULTS

Promoter level expression of CALML5 genes was significantly higher in thymic carcinomas than in type B3 thymomas. We further validated the results of the CAGE analysis in all 26 thymic carcinomas and 38 type B3 thymomas by immunohistochemistry (IHC). CALML5 was strongly expressed in the cytoplasm in 19 of 26 cases with thymic carcinoma, whereas positivity at the protein level was shown in two of 38 type B3 thymomas. Thus, the sensitivity (73.1%) and specificity (94.7%) of CALML5 as markers for immunohistochemical diagnosis of thymic carcinoma were extremely high.

CONCLUSION

We identified CALML5 as a potential marker for differentiating thymic squamous cell carcinoma from type B3 thymoma. It is assumed that future clinical use of CALML5 may improve the diagnostic accuracy of differentiating between these two diseases.

A Systematic Review of Host Genomic Variation and Neuropsychological Outcomes for Pediatric Cancer Survivors

Pediatric survivors of brain tumors and acute lymphoblastic leukemia (ALL) are at risk for long-term deficits in their neuropsychological functioning. Researchers have begun examining associations between germline single nucleotide polymorphisms (SNPs), which interact with cancer treatment, and neuropsychological outcomes. This review synthesizes the impact of treatment-related toxicity from germline SNPs by neuropsychological domain (i.e., working memory, processing speed, psychological functioning) in pediatric survivors. By focusing on specific neuropsychological domains, this review will examine outcome measurement and critique methodology. Fourteen studies were identified and included in this review using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). All studies were published in peer-reviewed journals in English by November 24th, 2021. Reviewed studies were not of sufficient quality for a meta-analysis due to varying measurement strategies, gaps in reported descriptive variables, and low power. All neuropsychological domains evaluated in this review had associations with SNPs, except fine motor and visual integration abilities. Only five SNPs had consistent neuropsychological findings in more than one study or cohort. Future research and replication studies should use validated measures of discrete skills that are central to empirically validated models of survivors' long-term outcomes (i.e., attention, working memory, processing speed). Researchers should examine SNPs across pathophysiological pathways to investigate additive genetic risk in pediatric cancer survivors. Two SNPs were identified that confer resiliency in neuropsychological functioning, and future work should investigate resiliency genotypes and their underlying biological mechanisms.

A Transcriptomic Analysis of Head and Neck Squamous Cell Carcinomas for Prognostic Indications

Survival analysis of the Cancer Genome Atlas (TCGA) dataset is a well-known method for discovering gene expression-based prognostic biomarkers of head and neck squamous cell carcinoma (HNSCC). A cutoff point is usually used in survival analysis for patient dichotomization when using continuous gene expression values. There is some optimization software for cutoff determination. However, the software's predetermined cutoffs are usually set at the medians or quantiles of gene expression values. There are also few clinicopathological features available in pre-processed datasets. We applied an in-house workflow, including data retrieving and pre-processing, feature selection, sliding-window cutoff selection, Kaplan-Meier survival analysis, and Cox proportional hazard modeling for biomarker discovery. In our approach for the TCGA HNSCC cohort, we scanned human protein-coding genes to find optimal cutoff values. After adjustments with confounders, clinical tumor stage and surgical margin involvement were found to be independent risk factors for prognosis. According to the results tables that show hazard ratios with Bonferroni-adjusted p values under the optimal cutoff, three biomarker candidates, CAMK2N1, CALML5, and FCGBP, are significantly associated with overall survival. We validated this discovery by using the another independent HNSCC dataset (GSE65858). Thus, we suggest that transcriptomic analysis could help with biomarker discovery. Moreover, the robustness of the biomarkers we identified should be ensured through several additional tests with independent datasets.

Identification of calmodulin-like protein 5 as tumor-suppressor gene silenced during early stage of carcinogenesis in squamous cell carcinoma of uterine cervix

In the course of identifying the molecular mechanism that is related to strong cell-cell adhesion in stratified structures of the squamous epithelium, calmodulin-like protein 5 (CALML5) was identified as a spinous structure-associated protein by producing monoclonal antibodies with the use of the crude intercellular portion of squamous tissue as an immunogen and by subsequent morphologic screening. By electrophoretic mobility shift assay (EMSA) and a series of mutagenesis studies, two transcription factors, ZNF750 and KLF4, by binding in line to the CALML5 gene promoter, were found to play a central role in CALML5 transcription. Knockdown of CALML5 by siRNA in the A431 cell line that expresses high levels of CALML5 resulted in the acceleration of wound confluence in a scratch assay, indicating that CALML5 functions as a tumor-suppressor in uterine cervical cancer. Immunohistochemical evaluation of squamous intraepithelial lesions, carcinoma in situ (CIS) and invasive uterine cancer, revealed a reduction in CALML5 expression during the stages of CIS through various molecular pathways including the blockage of the nuclear translocation of KLF4. Conversely, restoration of the nuclear translocation of KLF4 by inhibiting ERK-signaling reactivated CALML5 expression in ME180 cells expressing low levels of CALML5. Thus, alteration of the p63-ZNF750-KLF4 axis may result in critical functional loss of CALM-related genes during cancer progression. Although the morphological association of CALML5 with the spiny-structure in relation to cell motility is not clear, evaluation of CALML5 expression provides a useful diagnostic indicator of differentiating dysplasia, preinvasive and invasive cervical cancers.

Restoration of the reduced CLSP activity alleviates memory impairment in Alzheimer disease

Calmodulin-like skin protein (CLSP), a secreted peptide, inhibits neuronal death in cell-based Alzheimer's disease (AD) models and transgenic overexpression of the CLSP gene suppresses synaptic loss and memory impairment in AD model mice, APPswe/PS1dE9 double transgenic mice (APP/PS1 mice). Despite the anticipated role of CLSP as an AD-suppressing factor, it remains unanswered whether the insufficiency of the CLSP activity is linked to the AD pathogenesis. In this study, we first show that adiponectin, a CLSP potentiator/protector, dominantly determines the CLSP activity in the central nervous system where there are sufficient concentrations of CLSP, higher concentrations of CLSP inhibitors such as apolipoprotein E, and smaller concentrations of adiponectin. We next show that both the levels of brain adiponectin and the intraneuronal levels of SH3BP5, an important effector of the CLSP signal, are reduced in both AD patients and APP/PS1 mice. Finally, the restoration of the CLSP activity by subcutaneous injection of a hybrid peptide named CLSPCOL consisting of CLSP(1-61) and the collagen-homologous region of adiponectin, which has more potent neuroprotective activity than CLSP, is insensitive to the suppression by the CLSP inhibitors, and is efficiently recruited into brains, alleviates dementia and synaptic loss in the aged APP/PS1 mice. Collectively, these results suggest that the reduction in the CLSP activity, likely caused by the reduction in the levels of adiponectin, leads to the insufficient protection of neurons from neurotoxicity in the AD brains and the restoration of the CLSP activity is a promising strategy for the treatment of AD.

Identification of novel methylation markers in HPV-associated oropharyngeal cancer: genome-wide discovery, tissue verification and validation testing in ctDNA

Human papilloma virus (HPV)-associated oropharyngeal cancer (OPC) is an independent tumour type with regard to cellular, biological, and clinical features. The use of non-invasive biomarkers such as circulating tumour DNA (ctDNA) may be relevant in early diagnosis and eventually improve the outcomes of patients with head and neck squamous cell carcinoma (HNSCC). Genome-wide discovery using RNA sequencing and reduced representation bisulfite sequencing yielded 21 candidates for methylation-targeted genes. A verification study (252 HNSCC patients) using quantitative methylation-specific PCR (Q-MSP) identified 10 genes (ATP2A1, CALML5, DNAJC5G, GNMT, GPT, LY6D, LYNX1, MAL, MGC16275, and MRGPRF) that showed a significant increase recurrence in methylation groups with OPC. Further study on ctDNA using Q-MSP in HPV-associated OPC showed that three genes (CALML5, DNAJC5G, and LY6D) had a high predictive ability as emerging biomarkers for a validation set, each capable of discriminating between the plasma of the patients from healthy individuals. Among the 42 ctDNA samples, methylated CALML5, DNAJC5G, and LY6D were observed in 31 (73.8%), 19 (45.2%), and 19 (45.2%) samples, respectively. Among pre-treatment ctDNA samples, methylated CALML5, DNAJC5G, and LY6D were observed in 8/8 (100%), 7/8 (87.5%), and 7/8 (87.5%) samples, respectively. Methylated CALML5, DNAJC5G, and LY6D were found in 2/8 (25.0%), 0/8 (0%), and 1/8 (12.5%) of the final samples in the series, respectively. Here, we present the relationship between the methylation status of three specific genes and cancer recurrence for risk classification of HPV-associated OPC cases. In conclusion, ctDNA analysis has the potential to aid in determining patient prognosis and real-time surveillance for disease recurrences and serves as an alternative method of screening for HPV-associated OPC.

Molecular Mechanism of Epidermal Barrier Dysfunction as Primary Abnormalities

Epidermal barrier integrity could be influenced by various factors involved in epidermal cell differentiation and proliferation, cell–cell adhesion, and skin lipids. Dysfunction of this barrier can cause skin disorders, including eczema. Inversely, eczema can also damage the epidermal barrier. These interactions through vicious cycles make the mechanism complicated in connection with other mechanisms, particularly immunologic responses. In this article, the molecular mechanisms concerning epidermal barrier abnormalities are reviewed in terms of the following categories: epidermal calcium gradients, filaggrin, cornified envelopes, desquamation, and skin lipids. Mechanisms linked to ichthyoses, atopic dermatitis without exacerbation or lesion, and early time of experimental irritation were included. On the other hand, the mechanism associated with epidermal barrier abnormalities resulting from preceding skin disorders was excluded. The molecular mechanism involved in epidermal barrier dysfunction has been mostly episodic. Some mechanisms have been identified in cultured cells or animal models. Nonetheless, research into the relationship between the causative molecules has been gradually increasing. Further evidence-based systematic data of target molecules and their interactions would probably be helpful for a better understanding of the molecular mechanism underlying the dysfunction of the epidermal barrier.

Influence of genetic factors on long-term treatment related neurocognitive complications, and on anxiety and depression in survivors of childhood acute lymphoblastic leukemia: The Petale study

BACKGROUND

A substantial number of survivors of childhood acute lymphoblastic leukemia suffer from treatment-related late adverse effects including neurocognitive impairment. While multiple studies have described neurocognitive outcomes in childhood acute lymphoblastic leukemia (ALL) survivors, relatively few have investigated their association with individual genetic constitution.

METHODS

To further address this issue, genetic variants located in 99 genes relevant to the effects of anticancer drugs and in 360 genes implicated in nervous system function and predicted to affect protein function, were pooled from whole exome sequencing data of childhood ALL survivors (PETALE cohort) and analyzed for an association with neurocognitive complications, as well as with anxiety and depression. Variants that sustained correction for multiple testing were genotyped in entire cohort (n = 236) and analyzed with same outcomes.

RESULTS

Common variants in MTR, PPARA, ABCC3, CALML5, CACNB2 and PCDHB10 genes were associated with deficits in neurocognitive tests performance, whereas a variant in SLCO1B1 and EPHA5 genes was associated with anxiety and depression. Majority of associations were modulated by intensity of treatment. Associated variants were further analyzed in an independent SJLIFE cohort of 545 ALL survivors. Two variants, rs1805087 in methionine synthase, MTR and rs58225473 in voltage-dependent calcium channel protein encoding gene, CACNB2 are of particular interest, since associations of borderline significance were found in replication cohort and remain significant in combined discovery and replication groups (OR = 1.5, 95% CI, 1-2.3; p = 0.04 and; OR = 3.7, 95% CI, 1.25-11; p = 0.01, respectively). Variant rs4149056 in SLCO1B1 gene also deserves further attention since previously shown to affect methotrexate clearance and short-term toxicity in ALL patients.

CONCLUSIONS

Current findings can help understanding of the influence of genetic component on long-term neurocognitive impairment. Further studies are needed to confirm whether identified variants may be useful in identifying survivors at increased risk of these complications.

Molecular cloning and characterization of calmodulin-like protein CaLP from the Scleractinian coral Galaxea astreata

Optimal temperature and light are both necessary conditions for coral survival. Light enhances calcification, and thermal stress disrupts Ca2+ homeostasis. As calcium is involved in many important metabolic activities, in this study, we cloned the calmodulin-like protein (CaLP) gene of one of the scleractinian corals, Galaxea astreata. We also detected the relative mRNA expression levels of gaCaLP using the calcium channel blocker verapamil and CaCl2 treatment under conditions of light and dark, and compared expression levels under controlled temperature conditions. Full-length gaCaLP cDNA comprised 1290 nucleotides and contained 498 bp open reading frame that encoded a protein with 165 amino acids. With CaCl2, expression levels of gaCaLP only increased in the presence of light, suggesting that light may be a restrictive factor in CaLP expression when sufficient calcium is available in the environment. In addition, after verapami treatment, we noted that a down regulation of gaCaLP, suggesting that the expression of CaLP is closely related to extracellular Ca2+ influx. Under temperature stress at both high (30 °C) and low (20 °C) temperatures, expression levels of gaCaLP showed an initial increase, followed by a decreasing trend as treatment progressed. Expression levels reached their maximum value at 24 h. This result showed that CaLP participated in a temperature stress response, and Ca2+ homeostasis was disrupted during stress. The findings of the present study will help determine the function and regulatory mechanisms of gaCaLP.

Calmodulin-like skin protein protects against spatial learning impairment in a mouse model of Alzheimer disease

Humanin and calmodulin-like skin protein (CLSP) inhibits Alzheimer disease (AD)-related neuronal cell death via the heterotrimeric humanin receptor in vitro. It has been suggested that CLSP is a central agonist of the heterotrimeric humanin receptor in vivo. To investigate the role of CLSP in the AD pathogenesis in vivo, we generated mouse CLSP-1 transgenic mice, crossed them with the APPswe/PSEN1dE9 mice, a model mouse of AD, and examined the effect of CLSP over-expression on the pathological phenotype of the AD mouse model. We found that over-expression of the mouse CLSP-1 gene attenuated spatial learning impairment, the loss of a presynaptic marker synaptophysin, and the inactivation of STAT3 in the APPswe/PSEN1dE9 mice. On the other hand, CLSP over-expression did not affect levels of Aβ, soluble Aβ oligomers, or gliosis. These results suggest that the CLSP-mediated attenuation of memory impairment and synaptic loss occurs in an Aβ-independent manner. The results of this study may serve as a hint to the better understanding of the AD pathogenesis and the development of AD therapy.

Comparative proteomics analysis of primary cutaneous amyloidosis

Primary cutaneous amyloidosis (PCA) is a localized skin disorder that is characterized by the abnormal deposition of amyloid in the extracellular matrix (ECM) of the dermis. The pathogenesis of PCA is poorly understood. The objective of the present study was to survey proteome changes in PCA lesions in order to gain insight into the molecular basis and pathogenesis of PCA. Total protein from PCA lesions and normal skin tissue samples were extracted and analyzed using the isobaric tags for relative and absolute quantitation technique. The function of differentially expressed proteins in PCA were analyzed by gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) and protein-protein interaction analysis. The proteins that were most upregulated in PCA lesions were further analyzed by immunohistochemistry. A total of 1,032 proteins were identified in PCA lesions and control skin samples, with 51 proteins differentially expressed in PCA lesions, of which 27 were upregulated. In PCA lesions, the upregulated proteins were primarily extracellulary located. In addition, GO analysis indicated that the upregulated proteins were significantly enriched in the biological processes of epidermal development, collagen fiber organization and response to wounding (adjusted P<0.001). KEGG analysis indicated that the upregulated proteins were significantly enriched in the signaling pathways of cell communication, ECM receptor interaction and focal adhesion (adjusted P<0.001). Furthermore, the upregulated proteins were enriched in the molecular function of calcium ion binding, and the calcium binding proteins calmodulin-like protein 5, S100 calcium-binding protein A7 (S100A7)/fatty-acid binding protein and S100A8/A9 exhibited the highest levels of upregulation in PCA. This analysis of differentially expressed proteins in PCA suggests that increased focal adhesion, differentiation and wound healing is associated with the pathogenesis of PCA.

Calmodulin-like skin protein is downregulated in human cerebrospinal fluids of Alzheimer's disease patients with apolipoprotein E4; a pilot study using postmortem samples

OBJECTIVE

Calmodulin-like skin protein (CLSP) is a secreted peptide that inhibits neuronal cell death, linked to Alzheimer's disease (AD), by binding to the heterotrimeric humanin receptor and activating an intracellular survival pathway. CLSP is only expressed in skin keratinocytes and related epithelial cells, circulates in the blood stream, and passes the blood-cerebrospinal fluid (CSF) barrier. In the current study, we addressed the issues as to whether CLSP functions in the central nervous system and whether the concentration of CLSP is reduced in the CSFs of AD patients.

METHODS

Mice were intraperitoneally injected with 5 nmol of recombinant human CLSP. At 1h after the injection, the mice were sacrificed for the analysis of the existence of human CLSP in blood and interstitial fluid (ISF)-containing brain samples. Using postmortem CSF samples, we next determined the concentrations of CLSP in CSFs of human AD and control cases.

RESULTS

Intraperitoneally administered recombinant human CLSP circulated in the blood stream and reached the brain interstitial fluid. The concentrations of CLSP in CSFs of human AD and control cases are sufficient to exhibit the CLSP activity. Although the concentrations of CLSP in CSFs were not significantly different between AD and control cases, the concentrations of CLSP are lower in the AD cases with the apolipoprotein E4 genotype than in the AD cases without the apolipoprotein E4 genotype.

DISCUSSION

The first result indicates that CLSP enters the central nervous system through the blood-brain barrier. The second result suggests that CLSP functions in the human brains. The third result may exclude the possibility that the downregulation of the CLSP level is involved in the AD pathogenesis. The last result may contribute to the better understanding of the AD pathogenesis from the standpoint of the apolipoprotein E genotype.

The subclonal structure and genomic evolution of oral squamous cell carcinoma revealed by ultra-deep sequencing

Recent studies suggest that head and neck squamous cell carcinomas are very heterogeneous between patients; however the subclonal structure remains unexplored mainly due to studies using only a single biopsy per patient. To deconvolute the clonal structure and describe the genomic cancer evolution, we applied whole-exome sequencing combined with ultra-deep targeted sequencing on oral squamous cell carcinomas (OSCC). From each patient, a set of biopsies was sampled from distinct geographical sites in primary tumor and lymph node metastasis.We demonstrate that the included OSCCs show a high degree of inter-patient heterogeneity but a low degree of intra-tumor heterogeneity. However, some OSCC cancers contain complex subclonal architectures comprising distinct subclones only found in geographically distinct regions of the primary tumors. In several cases we find mutations in the primary tumor that are not present in the lymph node metastasis. We conclude that metastatic potential in our population is acquired early in tumor evolution as evident by the ongoing parallel evolution in several primary tumors.

"Ant-egg" cataract revisited

PURPOSE

Hereditary congenital cataract varies immensely concerning location and form of the lens opacities. A specific and very rare phenotype is called "ant-egg" cataract first described in 1900. "Ant-eggs" have previously been examined using light microscopy, backscattered electron imaging and X-ray scans and electron microscopy. The purpose of this study was to further characterize "ant-egg" cataract using modern technology and display the history of the "ant-eggs" after cataract extraction.

METHODS

"Ant-eggs" were examined using Heidelberg SPECTRALIS Optical Coherence Tomography (OCT)(Heidelberg Engineering, Heidelberg, Germany). Ten "ant-eggs" were extracted; four of these as well as control tissue were analyzed by mass spectrometry (AB Sciex). Proteins were identified and their approximate abundances were determined. Immunohistochemical staining was carried out on the remaining "ant-eggs" for cytokeratin and S100.

RESULTS

In anterior OCT-images, the "ant-egg" structures are localized on the iris. Comparative pictures showed that they stayed in the same location for more than 45 years. Mass spectrometry of "ant-eggs" yielded a proteome of 56 different proteins. Eighteen of the 56 "ant-egg" proteins (32 %) were neither present in our controls nor in a known fetal lens proteome. Among these were cytokeratin and Matrix-Gla protein. Immunohistochemical reactions were positive for cytokeratin and S100.

CONCLUSIONS

This study demonstrates the previously unknown protein composition of the "ant-egg" structures in "ant-egg" cataract. Eighteen of these proteins are not natively found in the human lens. Moreover, "ant-eggs" do not vary over time, after cataract extraction, regarding size and location.

CALML5 is a ZNF750- and TINCR-induced protein that binds stratifin to regulate epidermal differentiation

Outward migration of epidermal progenitors occurs with induction of hundreds of differentiation genes, but the identities of all regulators required for this process are unknown. We used laser capture microdissection followed by RNA sequencing to identify calmodulin-like 5 (CALML5) as the most enriched gene in differentiating outer epidermis. CALML5 mRNA was up-regulated by the ZNF750 transcription factor and then stabilized by the long noncoding RNA TINCR. CALML5 knockout impaired differentiation, abolished keratohyalin granules, and disrupted epidermal barrier function. Mass spectrometry identified SFN (stratifin/14-3-3σ) as a CALML5-binding protein. CALML5 interacts with SFN in suprabasal epidermis, cocontrols 13% of late differentiation genes, and modulates interaction of SFN to some of its binding partners. A ZNF750-TINCR-CALML5-SFN network is thus essential for epidermal differentiation.

Cutaneous expression of calcium/calmodulin-dependent protein kinase II in rats with type 1 and type 2 diabetes

Changes in calcium-calmodulin protein kinase II (CaMKII) have been well demonstrated in nervous tissue of diabetic animal models. Skin shares the same ectodermal origin as nervous tissue and it is often affected in diabetic patients. The goal of this study was to analyze expression of CaMKII in rat foot pad 2 weeks and 2 months after induction of diabetes type 1 and 2. Forty-two Sprague-Dawley rats were used. Diabetes mellitus type 1 (DM1) was induced with intraperitoneally (i.p.) injected 55 mg/kg of streptozotocin (STZ) and diabetes mellitus type 2 (DM2) with a combination of high-fat diet (HFD) and i.p. injection of low-dose STZ (35 mg/kg). Two weeks and two months following diabetes induction rats were sacrificed and skin samples from plantar surface of the both hind paws were removed. Immunohistochemistry was performed for detection of total CaMKII (tCaMKII) and its alpha isoform (pCaMKIIα). For detection of intraepidermal nerve fibers polyclonal antiserum against protein gene product 9.5 (PGP 9.5) was used. The results showed that CaMKII was expressed in the skin of both diabetic models. Total CaMKII was uniformly distributed throughout the epidermis and pCaMKIIα was limited to stratum granulosum. The tCaMKII and pCaMKIIα were not expressed in intraepidermal nerve fibers. Two weeks after induction of diabetes in rats there were no significant differences in expression of tCaMKII and pCaMKIIα between DM1 and DM2 compared to respective controls. In the 2-month experiments, significant increase in epidermal expression of tCaMKII and pCaMKIIα was observed in DM1 animals compared to controls, but not in DM2 animals. This study is the first description of cutaneous CaMKII expression pattern in a diabetic model. CaMKII could play a role in transformation of skin layers and contribute to cutaneous diabetic changes. Further research on physiological role of CaMKII in skin and its role in cutaneous diabetic complications should be undertaken in order to elucidate its function in epidermis.

Protective effects of Humanin and calmodulin-like skin protein in Alzheimer's disease and broad range of abnormalities

Humanin is a 24-amino acid, secreted bioactive peptide that prevents various types of cell death and improves some types of cell dysfunction. Humanin inhibits neuronal cell death that is caused by a familial Alzheimer's disease (AD)-linked gene via binding to the heterotrimeric Humanin receptor (htHNR). This suggests that Humanin may play a protective role in AD-related pathogenesis. Calmodulin-like skin protein (CLSP) has recently been identified as a physiological agonist of htHNR with 10(5)-fold more potent anti-cell death activity than Humanin. Humanin has also shown to have protective effects against some metabolic disorders. In this review, the broad range of functions of Humanin and the functions of CLSP that have been characterized thus far are summarized.

Protective role of the mitochondrial Lon protease 1 in ochratoxin A-induced cytotoxicity in HEK293 cells

Ochratoxin A (OTA) is a common kind of mycotoxin and food contaminant, which has various toxicological effects, especially nephrotoxicity. Our previous work about OTA-induced renal cytotoxicity indicated that mitochondrial Lon Protease 1 (Lonp1) might play a protective role. Lonp1 is a multifunctional ATP-dependent protease which mainly participates in mitochondrial proteolysis and protein quality control. The study aimed at probing how Lonp1 functioned in OTA-induced renal cytotoxicity. By means of RNA interference, we down-regulated the expression of Lonp1 in HEK293 cells. Cell viability results revealed that cells with Lonp1 deficiency were more vulnerable to OTA. Then we identified differentially expressed proteins between Lonp1 knock-down cells and scrambled control both in the absence and presence of OTA, using iTRAQ-based quantitative proteomics approach. Thirty-four proteins were differentially expressed as a result of Lonp1 deficiency, while forty-four proteins were differentially expressed in response to both Lonp1 deficiency and OTA treatment. By function summary and pathway analysis, we presumed that Lonp1 realized its protective function in the resistance to OTA-induced renal cytotoxicity via 4 processes: defensing against OTA-induced oxidative stress in the mitochondria; regulating protein synthesis, modification and repair; maintaining the balance of carbohydrate metabolism; and assisting in mtDNA maintenance.

BIOLOGICAL SIGNIFICANCE

OTA is a kind of mycotoxin that seriously threatens human health and has various toxicological effects. However, the mechanisms of its toxicity have not been exactly elucidated yet. The method of combination of RNAi and iTRAQ-based quantitative proteomics paves the way to gain a better understanding of the toxicity mechanisms of OTA. The present study, for the first time, verified the protective role of Lonp1 in OTA-induced renal cytotoxicity and clarified the defensive mechanism. Proteomic changes in Lonp1 deficient cells induced by OTA added new knowledge to OTA cytotoxicity.

Protein biomarkers in vernix with potential to predict the development of atopic eczema in early childhood

Background

Atopic eczema (AE) is a chronic inflammatory skin disease, which has increased in prevalence. Evidence points toward lifestyle as a major risk factor. AE is often the first symptom early in life later followed by food allergy, asthma, and allergic rhinitis. Thus, there is a great need to find early, preferentially noninvasive, biomarkers to identify individuals that are predisposed to AE with the goal to prevent disease development.

Objective

To investigate whether the protein abundances in vernix can predict later development of AE.

Methods

Vernix collected at birth from 34 newborns within the Assessment of Lifestyle and Allergic Disease During INfancy (ALADDIN) birth cohort was included in the study. At 2 years of age, 18 children had developed AE. Vernix proteins were identified and quantified with liquid chromatography coupled to tandem mass spectrometry.

Results

We identified and quantified 203 proteins in all vernix samples. An orthogonal projections to latent structures-discriminant analysis (OPLS-DA) model was found with R² = 0.85, Q² = 0.39, and discrimination power between the AE and healthy group of 73.5%. Polyubiquitin-C and calmodulin-like protein 5 showed strong negative correlation to the AE group, with a correlation coefficient of 0.73 and 0.68, respectively, and a P-value of 8.2 E-7 and 1.8 E-5, respectively. For these two proteins, the OPLS-DA model showed a prediction accuracy of 91.2%.

Conclusion

The protein abundances in vernix, and particularly that of polyubiquitin-C and calmodulin-like protein 5, are promising candidates as biomarkers for the identification of newborns predisposed to develop AE.

Specific expression of k63-linked ubiquitination of calmodulin-like protein 5 in breast cancer of premenopausal patients

PURPOSE

Posttranslational modifications such as ubiquitination regulate many functions of proteins by affecting their interaction with other molecules, their activity, and their subcellular localization. In cancer biology, the ubiquitin network has gained major interest. K63-linked ubiquitination has emerged as a posttranslational modification with functional consequences, as it acts in several processes such as protein trafficking, DNA repair, and inflammation. Moreover, k63-linked ubiquitination is involved in the regulation of carcinogenesis. Based on previous findings, the aim of this study was to evaluate the ubiquitination of CALML5 in breast cancer patients.

PATIENTS AND METHODS

The breast cancer cell lines SkBr3, MCF7, HCC1937, and BT474 as well as 23 tumor samples of patients with primary breast cancer and the normal adjacent breast tissue were analyzed by one-dimensional immunoblot.

RESULTS

Using specific antibodies against CALML5 and k63-linked ubiquitin, we demonstrate a k63-linked ubiquitination in the nuclear fraction of premenopausal breast cancer patients. K63-linked ubiquitination of CALML5 was found in breast cancer tissue, but not found in surrounding healthy tissue.

CONCLUSION

Our findings support the concept that ubiquitination of CALML5 in the nucleus is involved in the carcinogenesis of breast cancer in premenopausal women.

Loss of ELF3 immunoexpression is useful for detecting oral squamous cell carcinoma but not for distinguishing between grades of epithelial dysplasia

Early diagnosis and targeted therapy are crucial to mitigating the morbidity and mortality of oral squamous cell carcinoma. Among the potentially malignant oral disorders, epithelial dysplasia has known association with malignant transformation, but defensible gradation of dysplasia severity presents unmet challenges. Published microarray data has denoted dysregulation of CLSP, ELF3, IFI44, USP18, and CXCL13 genes in potentially malignant oral disorders. The present study investigated the diagnostic potential of these gene products to grade oral epithelial dysplasia severity. Archived biopsies from independent patient cohorts comprised "training" (n=107) and "test" (n=278) sample sets. Immunoreactivity for candidate markers was determined in the "training" set of normal oral mucosa (NOM), mild dysplasia (MD), moderate to severe dysplasia, and oral squamous cell carcinoma (OSCC). The diagnostic potential of ELF3 immunoscoring to improve detection and severity gradation of epithelial dysplasia was assessed with the "test" set. A reciprocal relationship between disease severity and immunoreactivity score for CLSP and ELF3 was observed (MD/NOM to OSCC: P<.08, Mann-Whitney U test), whereas elevated IFI44 immunostaining was present for OSCC compared to MD/NOM (P<.08, Mann-Whitney U test). Loss of ELF3 immunostaining effectively distinguished OSCC from non-malignant tissues (sensitivity=0.81; specificity=0.56; area under the curve [AUC]=0.68) but did not distinguish dysplasia from NOM (sensitivity=0.55; specificity=0.40; AUC=0.47) or moderate to severe dysplasia from MD (sensitivity=0.63; specificity=0.51; AUC=0.57). The results confirm via immunohistochemistry the relevance of published CLSP, ELF3, and IFI44 (but not USP18 or CXCL13) gene expression data to potentially malignant oral lesion severity. Loss of ELF3 immunostaining discriminated OSCC from dysplasia but was unreliable for grading dysplasia severity.

Cytokines and the skin barrier

The skin is the largest organ of the human body and builds a barrier to protect us from the harmful environment and also from unregulated loss of water. Keratinocytes form the skin barrier by undergoing a highly complex differentiation process that involves changing their morphology and structural integrity, a process referred to as cornification. Alterations in the epidermal cornification process affect the formation of the skin barrier. Typically, this results in a disturbed barrier, which allows the entry of substances into the skin that are immunologically reactive. This contributes to and promotes inflammatory processes in the skin but also affects other organs. In many common skin diseases, including atopic dermatitis and psoriasis, a defect in the formation of the skin barrier is observed. In these diseases the cytokine composition within the skin is different compared to normal human skin. This is the result of resident skin cells that produce cytokines, but also because additional immune cells are recruited. Many of the cytokines found in defective skin are able to influence various processes of differentiation and cornification. Here we summarize the current knowledge on cytokines and their functions in healthy skin and their contributions to inflammatory skin diseases.

Secreted calmodulin-like skin protein inhibits neuronal death in cell-based Alzheimer's disease models via the heterotrimeric Humanin receptor

Humanin is a secreted bioactive peptide that is protective in a variety of death models, including cell-based neuronal death models related to Alzheimer's disease (AD). To mediate the protective effect in AD-related death models, Humanin signals via a cell-surface receptor that is generally composed of three subunits: ciliary neurotrophic factor receptor α, WSX-1 and gp130 (heterotrimeric Humanin receptor; htHNR). However, the protective effect of Humanin via the htHNR is weak (EC₅₀=1–10 μℳ); therefore, it is possible that another physiological agonist for this receptor exists in vivo. In the current study, calmodulin-like skin protein (CLSP), a calmodulin relative with an undefined function, was shown to be secreted and inhibit neuronal death via the htHNR with an EC₅₀ of 10–100 pℳ. CLSP was highly expressed in the skin, and the concentration in circulating normal human blood was ∼5 nℳ. When administered intraperitoneally in mice, recombinant CLSP was transported across the blood-cerebrospinal fluid (CSF)-barrier and its concentration in the CSF reaches 1/100 of its serum concentration at 1 h after injection. These findings suggest that CLSP is a physiological htHNR agonist.

Divers models of divalent cation interaction to calcium-binding proteins: techniques and anthology

Intracellular Ca(2+)-binding proteins (CaBPs) are sensors of the calcium signal and several of them even shape the signal. Most of them are equipped with at least two EF-hand motifs designed to bind Ca(2+). Their affinities are very variable, can display cooperative effects, and can be modulated by physiological Mg(2+) concentrations. These binding phenomena are monitored by four major techniques: equilibrium dialysis, fluorimetry with fluorescent Ca(2+) indicators, flow dialysis, and isothermal titration calorimetry. In the last quarter of the twentieth century reports on the ion-binding characteristics of several abundant wild-type CaBPs were published. With the advent of recombinant CaBPs it became possible to determine these properties on previously inaccessible proteins. Here I report on studies by our group carried out in the last decade on eight families of recombinant CaBPs, their mutants, or truncated domains. Moreover this chapter deals with the currently used methods for quantifying the binding of Ca(2+) and Mg(2+) to CaBPs.

Global expression profiling in atopic eczema reveals reciprocal expression of inflammatory and lipid genes

BACKGROUND

Atopic eczema (AE) is a common chronic inflammatory skin disorder. In order to dissect the genetic background several linkage and genetic association studies have been performed. Yet very little is known about specific genes involved in this complex skin disease, and the underlying molecular mechanisms are not fully understood.

METHODOLOGY/FINDINGS

We used human DNA microarrays to identify a molecular picture of the programmed responses of the human genome to AE. The transcriptional program was analyzed in skin biopsy samples from lesional and patch-tested skin from AE patients sensitized to Malassezia sympodialis (M. sympodialis), and corresponding biopsies from healthy individuals. The most notable feature of the global gene-expression pattern observed in AE skin was a reciprocal expression of induced inflammatory genes and repressed lipid metabolism genes. The overall transcriptional response in M. sympodialis patch-tested AE skin was similar to the gene-expression signature identified in lesional AE skin. In the constellation of genes differentially expressed in AE skin compared to healthy control skin, we have identified several potential susceptibility genes that may play a critical role in the pathological condition of AE. Many of these genes, including genes with a role in immune responses, lipid homeostasis, and epidermal differentiation, are localized on chromosomal regions previously linked to AE.

CONCLUSIONS/SIGNIFICANCE

Through genome-wide expression profiling, we were able to discover a distinct reciprocal expression pattern of induced inflammatory genes and repressed lipid metabolism genes in skin from AE patients. We found a significant enrichment of differentially expressed genes in AE with cytobands associated to the disease, and furthermore new chromosomal regions were found that could potentially guide future region-specific linkage mapping in AE. The full data set is available at http://microarray-pubs.stanford.edu/eczema.

Immunopathogenesis of psoriasis

Psoriasis is a chronic skin disease that affects about 1.5% of the Caucasian population and is characterized by typical macroscopic and microscopic skin alterations. Psoriatic lesions are sharply demarcated, red and slightly raised lesions with silver-whitish scales. The microscopic alterations of psoriatic plaques include an infiltration of immune cells in the dermis and epidermis, a dilatation and an increase in the number of blood vessels in the upper dermis, and a massively thickened epidermis with atypical keratinocyte differentiation. It is considered a fact that the immune system plays an important role in the pathogenesis of psoriasis. Since the early 1990s, it has been assumed that T1 cells play the dominant role in the initiation and maintenance of psoriasis. However, the profound success of anti-tumor necrosis factor-alpha therapy, when compared with T-cell depletion therapies, should provoke us to critically re-evaluate the current hypothesis for psoriasis pathogenesis. Recently made discoveries regarding other T-cell populations such as Th17 and regulatory T cells, dendritic cells, macrophages, the keratinocyte signal transduction and novel cytokines including interleukin (IL)-22, IL-23 and IL-20, let us postulate that the pathogenesis of psoriasis consists of distinct subsequent stages, in each of them different cell types playing a dominant role. Our model helps to explain the varied effectiveness of the currently tested immune modulating therapies and may enable the prediction of the success of future therapies.

Role of Scarf and Its Binding Target Proteins in Epidermal Calcium Homeostasis

The novel Ca2+-binding protein, Scarf (skin calmodulin-related factor) belongs to the calmodulin-like protein family and is expressed in the differentiated layers of the epidermis. To determine the roles of Scarf during stratification, we set out to identify the binding target proteins by affinity chromatography and subsequent analysis by mass spectrometry. Several binding factors, including 14-3-3s, annexins, calreticulin, ERp72 (endoplasmic reticulum protein 72), and nucleolin, were identified, and their interactions with Scarf were corroborated by co-immunoprecipitation and co-localization analyses. To further understand the functions of Scarf in epidermis in vivo, we altered the epidermal Ca2+ gradient by acute barrier disruption. The change in the expression levels of Scarf and its binding target proteins were determined by immunohistochemistry and Western blot analysis. The expression of Scarf, annexins, calreticulin, and ERp72 were up-regulated by Ca2+ gradient disruption, whereas the expression of 14-3-3s and nucleolin was reduced. Because annexins, calreticulin, and ERp72 have been implicated in Ca2+-induced cellular trafficking, including the secretion of lamellar bodies and Ca2+ homeostasis, we propose that the interaction of Scarf with these proteins might be crucial in the process of barrier restoration. On the other hand, down-regulation of 14-3-3s and nucleolin is potentially involved in the process of keratinocyte differentiation and growth inhibition. The calcium-dependent localization and up-regulation of Scarf and its binding target proteins were studied in mouse keratinocytes treated with ionomycin and during the wound-healing process. We found increased expression and nuclear presence of Scarf in the epidermis of the wound edge 4 and 7 days post-wounding, entailing the role of Scarf in barrier restoration. Our results suggest that Scarf plays a critical role as a Ca2+ sensor, potentially regulating the function of its binding target proteins in a Ca2+-dependent manner in the process of restoration of epidermal Ca2+ gradient as well as during epidermal barrier formation.

Mechanisms regulating epithelial stratification

The epidermis is a stratified epithelium that functions as a barrier protecting the organism from dehydration, mechanical trauma, and microbial insults. This barrier function is established during embryogenesis through a complex and tightly controlled stratification program. Whereas the morphological changes that occur during epidermal development have been extensively studied, the molecular mechanisms that govern this process remain poorly understood. In this review we summarize the current advances that have been made in understanding the molecular mechanisms that regulate epidermal morphogenesis.

Proteomic analysis of the response of EpiDermTM cultures to sodium lauryl sulphate

The analysis of EpiDerm cultures treated with the known skin irritant sodium lauryl sulphate (SLS) was performed using 2D-gel electrophoresis in order to understand the mechanism of action and thereby identify novel markers of skin irritation. A range of both broad and narrow pH gradient first-dimension gels were run (pH 4-7, 6-11, 4-5, 5-6 and 6-9) consistently followed by 12% SDS-PAGE in the second-dimension. Following treatment of EpiDerm with SLS, 67 proteins of interest were identified, of which 8 were selected as interesting: calmodulin-like skin protein, involucrin, epithelial cell marker protein, HS1, peroxiredoxin 1, serine protease inhibitor, KIAA0117 and ribosomal protein L17. Involucrin was confirmed as being up-regulated by both ELISA and Western blotting. The use of proteomics has identified a number of proteins which could be used as general markers for skin irritation and which may in particular be of value for the development of in vitro predictive models.

A structural and dynamic characterization of the EF-hand protein CLSP

The structure and dynamics of human calmodulin-like skin protein (CLSP) have been characterized by NMR spectroscopy. The mobility of CLSP has been found to be different for the N-terminal and C-terminal domains. The isolated domains were also expressed and analyzed. The structure of the isolated C-terminal domain is presented. The N-terminal domain is characterized by four stable helices, which experience large fluctuations. This is shown to be due to mutations in the hydrophobic core. The overall N-terminal domain behavior is similar both in the full-length protein and in the isolated domain. By exploiting the capability of Tb3+ bound to CLSP to induce partial orientation of the molecule in a magnetic field, restricted motion of one domain with respect to the other was proved. By using NMR, ITC, and ESI-MS, the calcium and magnesium binding properties were investigated. Finally, CLSP is framed into the evolutionary scheme of the calmodulin-like family.

Significance of the extra C-terminal tail of CaLP, a novel calmodulin-like protein involved in oyster calcium metabolism

Oyster (Pinctada fucata) calmodulin-like protein (CaLP), containing a C-terminally extra hydrophilic tail (150D-161K), is a novel protein involved in the regulation of oyster calcium metabolism. To investigate the importance of the extra fragment to the Ca(2+)/Mg(2+)-dependent conformational changes in the intact CaLP molecule and the interactions between CaLP and its target proteins, a truncated CaLP mutant (M-CaLP) devoid of the extended C-terminus was constructed and overexpressed in Escherichia coli. The conformational characteristics of M-CaLP were studied by CD and fluorescence spectroscopy and compared with those of the oyster CaM and CaLP. The far-UV CD results reveal that the extra tail has a strong effect on the Ca(2+)-induced, but a relatively weak effect on the Mg(2+)-induced conformational changes in CaLP. However, upon Ca2+ or Mg2+ binding, only slight changes for intrinsic phenylalanine and tyrosine fluorescence spectra between M-CaLP and CaLP are observed. Our results also indicate that the extra tail can significantly decrease the exposure of the hydrophobic patches in CaLP. Additionally, affinity chromatography demonstrates that the target binding of CaLP is greatly influenced by its additional tail. All our results implicate that the extra tail may play some important roles in the interactions between CaLP and its targets in vivo.

Influence of calcium on the proteolytic degradation of the calmodulin-like skin protein (calmodulin-like protein 5) in psoriatic epidermis

The calmodulin-like skin protein (CLSP) or so-called calmodulin-like protein 5, a recently discovered skin-specific calcium-binding protein, is closely related to keratinocyte differentiation. The 16-kDa protein is proteolytically degraded in the upper layers of the stratum corneum (SC) of healthy skin. With the use of specific new monoclonal antibodies to CLSP, we were able to demonstrate that the abnormal elevated levels of CLSP, characteristic of psoriatic epidermis, were probably not due to an overexpression of the protein, but most likely the result of its non-degradation. Further in vitro experiments using recombinant CLSP and in situ data clearly showed that calcium protected and chelator accelerated CLSP degradation. These data indicate that CLSP degradation in the SC of psoriatic skin might be hindered by the abnormally elevated calcium concentration. No degradation of CLSP in psoriatic epidermis keeping its ability to bind protein as transglutaminase 3 may have a physiological role in skin diseases such as psoriasis.

IL-22 regulates the expression of genes responsible for antimicrobial defense, cellular differentiation, and mobility in keratinocytes: a potential role in psoriasis

IL-22 is an IFN-IL-10 cytokine family member, which is produced by activated Th1 and NK cells and acts primarily on epithelial cells. Here we demonstrate that IL-22, in contrast to its relative IFN-gamma, regulates the expression of only a few genes in keratinocytes. This is due to varied signal transduction. Gene expressions regulated by IL-22 should enhance antimicrobial defense [psoriasin (S100A7), calgranulin A (S100A8), calgranulin B (S100A9)], inhibit cellular differentiation (e.g., profilaggrin, keratins 1 and 10, kallikrein 7), and increase cellular mobility [e.g., matrix metalloproteinease 1 (MMP1, collagenase 1), MMP3 (stromelysin 1), desmocollin 1]. In contrast, IFN-gamma favored the expression of MHC pathway molecules, adhesion molecules, cytokines, chemokines, and their receptors. The IL-22 effects were transcriptional and either independent of protein synthesis and secretion, or mediated by a secreted protein. Inflammatory conditions, but not keratinocyte differentiation, amplified the IL-22 effects. IL-22 application in mice enhanced cutaneous S100A9 and MMP1 expression. High IL-22 levels in psoriatic skin were associated with strongly up-regulated cutaneous S100A7, S100A8, S100A9, and MMP1 expression. Psoriatic patients showed strongly elevated IL-22 plasma levels, which correlated with the disease severity. Expression of IL-22 and IL-22-regulated genes was reduced by anti-psoriatic therapy. In summary, despite similarities, IFN-gamma primarily amplifies inflammation, while IL-22 may be important in the innate immunity and reorganization of epithelia.

Plant calmodulins and calmodulin-related proteins: multifaceted relays to decode calcium signals

The calmodulin (CaM) family is a major class of calcium sensor proteins which collectively play a crucial role in cellular signaling cascades through the regulation of numerous target proteins. Although CaM is one of the most conserved proteins in all eukaryotes, several features of CaM and its downstream effector proteins are unique to plants. The continuously growing repertoire of CaM-binding proteins includes several plant-specific proteins. Plants also possess a particular set of CaM isoforms and CaM-like proteins (CMLs) whose functions have just begun to be elucidated. This review summarizes recent insights that help to understand the role of this multigene family in plant development and adaptation to environmental stimuli.

Microarray analysis of gene expression in cultured skin substitutes compared with native human skin

Cultured skin substitutes (CSS), prepared using keratinocytes, fibroblasts, and biopolymers, can facilitate closure of massive burn wounds by increasing the availability of autologous tissue for grafting. But because they contain only two cell types, skin substitutes cannot replace all of the functions of native human skin. To better understand the physiological and molecular differences between CSS and native skin, we undertook a comprehensive analysis of gene expression in native skin, cultured keratinocytes, cultured fibroblasts, and skin substitutes using Affymetrix gene chip microarrays. Hierarchical tree clustering identified six major clusters of coordinately regulated genes, using a list of 1030 genes that were the most differentially expressed between groups. These clusters correspond to biomarker pools representing expression signatures for native skin, fibroblasts, keratinocytes, and cultured skin. The expression analysis revealed that entire clusters of genes were either up- or downregulated upon combination of fibroblasts and keratinocytes in cultured skin grafts. Further, several categories of genes were overexpressed in CSS compared with native skin, including genes associated with hyperproliferative skin or activated keratinocytes. The observed pattern of expression indicates that CSS in vitro, which display a well-differentiated epidermal layer, exhibit a hyperproliferative phenotype similar to wounded native skin.

The temporal and spatial expression of the novel Ca++-binding proteins, Scarf and Scarf2, during development and epidermal differentiation

During the process of epidermal differentiation, intracellular and extracellular calcium (Ca++) concentrations induce an array of signaling pathways . Keratinocytes follow a complex Ca++-dependent program of differentiation moving from the basal proliferative layer, through the spinous and granular differentiated layers to ultimately culminate in the formation of the cornified layer of the epidermis. Members of the Ca++-binding proteins play a central role in the transduction of Ca++ signals. Utilizing a suppressive subtractive hybridization screen comparing basal and differentiated keratinocytes, we identified the novel Ca++-binding protein genes, Scarf (skin Calmodulin-related factor) and Scarf2, which have homology to calmodulin (CaM). In this study, we present a comprehensive analysis of the expression pattern for Scarf and Scarf2 transcripts and proteins in the developing mouse. To examine Scarf2 expression during embryogenesis, we performed in situ hybridization, and detected expression in the hair follicle, skin and nasal epithelium. These results showed substantial overlap with the previously reported Scarf gene expression [Hwang, M., Morasso, M.I., 2003. The novel murine Ca2+-binding protein, Scarf, is differentially expressed during epidermal differentiation. J. Biol. Chem. 278, 47827-47833]. Comparing the expression patterns of Scarf and Scarf2 proteins in neonatal and adult mouse skin with several structural epidermal proteins, i.e. keratin 14 (K14), keratin 1 (K1), loricrin (LOR) and filaggrin (FIL) showed that their expression overlaps K1, an early marker of keratinocyte differentiation. Interestingly, Scarf and Scarf2 were also detected in the tongue and oral epithelia, rib bone undergoing ossification and in the medullar region of thymus.

cDNA cloning and characterization of a novel calmodulin-like protein from pearl oyster Pinctada fucata

Calcium metabolism in oysters is a very complicated and highly controlled physiological and biochemical process. However, the regulation of calcium metabolism in oyster is poorly understood. Our previous study showed that calmodulin (CaM) seemed to play a regulatory role in the process of oyster calcium metabolism. In this study, a full-length cDNA encoding a novel calmodulin-like protein (CaLP) with a long C-terminal sequence was identified from pearl oyster Pinctada fucata, expressed in Escherichia coli and characterized in vitro. The oyster CaLP mRNA was expressed in all tissues tested, with the highest levels in the mantle that is a key organ involved in calcium secretion. In situ hybridization analysis reveals that CaLP mRNA is expressed strongly in the outer and inner epithelial cells of the inner fold, the outer epithelial cells of the middle fold, and the dorsal region of the mantle. The oyster CaLP protein, with four putative Ca(2+)-binding domains, is highly heat-stable and has a potentially high affinity for calcium. CaLP also displays typical Ca(2+)-dependent electrophoretic shift, Ca(2+)-binding activity and significant Ca(2+)-induced conformational changes. Ca(2+)-dependent affinity chromatography analysis demonstrated that oyster CaLP was able to interact with some different target proteins from those of oyster CaM in the mantle and the gill. In summary, our results have demonstrated that the oyster CaLP is a novel member of the CaM superfamily, and suggest that the oyster CaLP protein might play a different role from CaM in the regulation of oyster calcium metabolism.

Identification and Characterization of a Novel Retroviral-Like Aspartic Protease Specifically Expressed in Human Epidermis

Proteases play a pivotal role in epidermal differentiation and desquamation. Separation of a total protein extract from human reconstructed epidermis by two-dimensional gel electrophoresis and subsequent peptide analysis of a specific protein spot identified a new protein exhibiting similarities with the retroviral aspartic protease family. Cloning of the corresponding full-length cDNA revealed an open reading frame encoding for a new protease of 343 amino acids, containing a putative aspartic protease catalytic domain. We named this protein Skin ASpartic Protease (SASPase). RT-PCR and northern blot analysis of various human tissues revealed that SASPase was specifically expressed within the epidermis. Immunohistochemical analysis showed a particularly intense expression restricted to the granular layers, whereas in diseased skin, its expression was changed. Western blot analysis, using a monoclonal antibody, revealed the expression of two forms of the enzyme: a 28 kDa putative proform and the active 14 kDa form. Recombinant truncated SASPase (SASP28) was generated from a prokaryotic expression system in Escherichia coli as a fusion protein with GST. SASP28 degraded insulin and to a lesser extent casein with a pH optimum of 5. As seen for retroviral proteases, an auto-activation processing was evidenced, generating a 14 kDa protein (SASP14). Site-directed mutagenesis inhibited auto-activation of the enzyme. Indinavir, a potent HIV protease inhibitor used in AIDS therapy, had a significant inhibitory effect on rSASPase auto-activation, which could explain its side effects on skin.

IL-22 inhibits epidermal differentiation and induces proinflammatory gene expression and migration of human keratinocytes

IL-22 belongs to a family of cytokines structurally related to IL-10, including IL-19, IL-20, IL-24, and IL-26. In contrast to IL-10, IL-22 has proinflammatory activities. IL-22 signals through a class II cytokine receptor composed of an IL-22-binding chain, IL-22RA1, and the IL-10RB subunit, which is shared with the IL-10R. In the present study, we show that short-term cultured human epidermal keratinocytes express a functional IL-22R but no IL-10R. Accordingly, IL-22 but not IL-10 induces STAT3 activation in keratinocytes. Using a cDNA array screening approach, real-time RT-PCR, and Western blot analysis, we demonstrate that IL-22 up-regulates, in a dose-dependent manner, the expression of S100A7, S100A8, S100A9, a group of proinflammatory molecules belonging to the S100 family of calcium-binding proteins, as well as the matrix metalloproteinase 3, the platelet-derived growth factor A, and the CXCL5 chemokine. In addition, IL-22 induces keratinocyte migration in an in vitro injury model and down-regulates the expression of at least seven genes associated with keratinocyte differentiation. Finally, we show that IL-22 strongly induces hyperplasia of reconstituted human epidermis. Taken together, these results suggest that IL-22 plays an important role in skin inflammatory processes and wound healing.

The novel murine Ca2+-binding protein, Scarf, is differentially expressed during epidermal differentiation

Calcium (Ca2+) signaling-dependent systems, such as the epidermal differentiation process, must effectively respond to variations in Ca2+ concentration. Members of the Ca2+-binding proteins play a central function in the transduction of Ca2+ signals, exerting their roles through a Ca2+-dependent interaction with their target proteins, spatially and temporally. By performing a suppression subtractive hybridization screen we identified a novel mouse gene, Scarf (skin calmodulin-related factor), which has homology to calmodulin (CaM)-like Ca2+-binding protein genes and is exclusively expressed in differentiating keratinocytes in the epidermis. The Scarf open reading frame encodes a 148-amino acid protein that contains four conserved EF-hand motifs (predicted to be Ca2+-binding domains) and has homology to mouse CaM, human CaM-like protein, hClp, and human CaM-like skin protein, hClsp. The functionality of Scarf EF-hand domains was assayed with a radioactive Ca2+-binding method. By Southern blot and computational genome sequence analysis, a highly related gene, Scarf2, was found 15 kb downstream of Scarf on mouse chromosome 13. The functional Scarf Ca2+-binding domains suggest a role in the regulation of epidermal differentiation through the control of Ca2+-mediated signaling.

Analysis of proteins with caseinolytic activity in a human stratum corneum extract revealed a yet unidentified cysteine protease and identified the so-called "stratum corneum thiol protease" as cathepsin l2

Desquamation is described as a protease-dependent phenomenon where serine proteases with a basic pH optimum play a key role. Recently proteases with an acidic pH optimum were identified in the stratumcorneum and associated with desquamation, e.g., cathepsin D and the stratum corneum thiol protease. The purpose of this study was to investigate if human stratum corneum contains proteases different from the above, exhibiting similar properties. After gel filtration, we identified four distinct proteolytic activities in a human stratum corneum extract, a cathepsin-E-like activity (80 kDa), a cathepsin-D activity (40 kDa), a yet unknown cathepsin-L-like form (28 kDa) exhibiting the highest caseinolytic activity, and a chymotrypsin-like protein (24 kDa) containing the acidic activity of the well described stratum corneum chymotryptic enzyme. We named the new 28 kDa protease stratum corneum cathepsin-L-like enzyme. Characterization of stratum corneum cathepsin-L-like enzyme provided clear evidence that this new protease, despite its membership to the cathepsin-L-like family, is distinct from cathepsin L and from the recently described stratum corneum thiol protease. Its ability to hydrolyze corneodesmosin, a marker of corneocyte cohesion, was in favor of a role of stratum corneum cathepsin-L-like enzyme in the desquamation process. A more detailed analysis did not allow us to identify stratum corneum cathepsin-L-like enzyme at the molecular level but revealed that stratum corneum thiol protease is identical with the recently described cathepsin L2 protease. Reverse transcription polymerase chain reaction studies and the use of a specific antibody revealed that, in contrast to earlier reports, expression of stratum corneum thiol protease in human epidermis is not related to keratinocyte differentiation. Our results indicate that the stratum corneum thiol protease is probably expressed as a pro-enzyme in the lower layers of the epidermis and in part activated by a yet unidentified mechanism in the upper layers during keratinocyte differentiation.

Charge derivatization by 4-sulfophenyl isothiocyanate enhances peptide sequencing by post-source decay matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

High-sensitivity, rapid identification of proteins in proteomic studies normally uses a combination of one- or two-dimensional electrophoresis together with mass spectrometry. The simplicity and sensitivity of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) have increased its application in recent years. The most common method of 'peptide fingerprinting' often may not provide robust identification. Normally additional sequence information by post-source decay (PSD) MALDI-TOFMS provides additional constraints for database searches to achieve highly confident results. Here we describe a derivatization procedure to facilitate the acquisition of such sequence information. Peptide digests from a skin-expressed protein were modified with 4-sulfophenyl isothiocyanate. The resulting peptides carry a fixed negative charge at the N-terminal end and the resulting PSD spectrum is dominated by C-terminal y-type ions. The sequence information in most cases can be obtained manually or with simple programming tools. Methods of optimizing the procedure and increasing the sensitivity are discussed.