Physiological and pathological implications of laminins: From the gene to the protein

Matrikines in the skin: Origin, effects, and therapeutic potential

The extracellular matrix (ECM) represents a complex multi-component environment that has a decisive influence on the biomechanical properties of tissues and organs. Depending on the tissue, ECM components are subject to a homeostasis of synthesis and degradation, a subtle interplay that is influenced by external factors and the intrinsic aging process and is often disturbed in pathologies. Upon proteolytic cleavage of ECM proteins, small bioactive peptides termed matrikines can be formed. These bioactive peptides play a crucial role in cell signaling and contribute to the dynamic regulation of both physiological and pathological processes such as tissue remodeling and repair as well as inflammatory responses. In the skin, matrikines exert an influence for instance on cell adhesion, migration, and proliferation as well as vasodilation, angiogenesis and protein expression. Due to their manifold functions, matrikines represent promising leads for developing new therapeutic options for the treatment of skin diseases. This review article gives a comprehensive overview on matrikines in the skin, including their origin in the dermal ECM, their biological effects and therapeutic potential for the treatment of skin pathologies such as melanoma, chronic wounds and inflammatory skin diseases or for their use in anti-aging cosmeceuticals.

Hyperosmolar environment and salivary gland epithelial cells increase extra-cellular matrix remodeling and lymphocytic infiltration in Sjögren's syndrome

Salivary gland epithelial cells (SGECs) play an active role in primary Sjogren's syndrome (pSS) pathogenesis. Quantitative and qualitative abnormalities of saliva might expose SGECs to chronic hyperosmolarity. We aimed to decipher the links between hyperosmolar stimulation of SGECs and lymphocytic infiltration of the salivary glands (SG) observed in pSS. RNAseq was performed on NS-SV-AC cells stimulated with hyperosmolar media containing NaCl (100 mM) or sucrose (200 mM), or with iso-osmolar (Iso) medium. RNAseq was performed on primary cultured SGECs from pSS and controls, in the presence or not of B cells. Hyperosmolar stimulation of NS-SV-AC-cells identified an upregulation of interferon-induced (MX1, IFIT2) and MMPs genes. Enrichment analysis revealed an over-representation of fibrosis pathway. In parallel, RNAseq of SGECs comparing pSS to controls identified an over-representation of a pathway involving MMPs. Given the unexpected upregulation of collagen (COL3A1, COL1A2) and ADAMTS genes in pSS SGECs, we hypothesized that SGECs might undergo epithelial-mesenchymal transition. ZEB2 was upregulated and SLUG was down regulated in SGECs from pSS versus controls. MMP24 and ZEB2 were higher in SGECs from pSS with a focus score ≥1 versus <1. Lastly, SGECs cocultured with B cells expressed higher levels of COL1A2. These results suggest the existence of a vicious circle. Alteration of SGECs in pSS participates in the establishment of a hyperosmolar microenvironment, which in turn promotes SGECs transcriptomic modifications. These modifications include extracellular matrix remodeling and promote SG lymphocytic infiltration.

Use of T1ρMR imaging in Sjögren's syndrome with normal appearing parotid glands: Initial findings

PURPOSE

To explore the feasibility of parotid spin-lattice relaxation time in the rotating frame (T1ρ) MR imaging in the diagnosis of Sjögren's syndrome (SS) without morphological changes of the parotid glands.

MATERIALS AND METHODS

The study enrolled 32 consecutive SS patients without morphological changes of parotid glands and 32 age- and gender-matched healthy volunteers who underwent parotid 3.0 Tesla MR imaging, including T1ρ sequences. Follow-up imaging was performed at 3 months. T1 signal intensities and T1ρ values of bilateral parotid glands were compared using paired samples t-test. Parotid T1 signal intensities and T1ρ values were compared using two independent samples t-test. Diagnostic performance of the parotid T1ρ values was evaluated by receiver operating characteristic analysis. The intraclass correlation coefficient (ICC) was calculated to evaluate the reproducibility of parotid T1ρ measurements.

RESULTS

There were no significant differences of T1 signal intensities and T1ρ values between bilateral parotid glands in SS patients and healthy volunteers (P = 0.170, 0.886 and 0.942, 0.229). The parotid T1ρ values of SS patients (96.47 ± 15.38 ms) were significantly higher than those of healthy volunteers (84.25 ± 6.11 ms) (P < 0.001), while there were no significant differences of T1 signal intensities between SS patients and healthy volunteers (P = 0.655). With a cutoff value of 88.02 ms, the sensitivity and specificity of the parotid T1ρ value was 75.0% and 100.0% in the diagnosis of SS. The reproducibility of parotid T1ρ measurement was excellent (ICC: 0.934-0.995).

CONCLUSION

Parotid T1ρ MR imaging held a potential role in diagnosing SS without morphological changes of parotid glands.

LEVEL OF EVIDENCE

2 J. Magn. Reson. Imaging 2017;45:1005-1012.

Surgical margins in head and neck squamous cell carcinoma: Effect of heat artifact on immunohistochemistry as a future tool for assessment

BACKGROUND

Margins in head and neck squamous cell carcinoma (HNSCC) are determined by morphological changes assessed via hematoxylin-eosin staining. Physiological changes may not be detected by this technique. The purpose of this study was to determine if a protein biomarker, laminin-332γ2, overexpressed in cancer cells at the invasive front in HNSCC, remains unaffected by heat produced during resection, supporting a role for immunohistochemistry assessment of margins.

METHODS

Archived tissue blocks from glottic squamous cell carcinomas (SCCs) resected by CO2 laser likely to contain both cancer cells and artifact were identified; 129-paired slides were obtained. One slide of each pair was stained with hematoxylin-eosin; the second stained for laminin-332γ2. The presence of cancer cells, artifact, and positive laminin-332γ2 staining was recorded. Twenty-seven pairs met the inclusion criteria.

RESULTS

Immunohistochemistry staining of laminin-332γ is preserved in presence of heat artifact.

CONCLUSION

This study supports use of immunohistochemistry to assess margins. © 2016 Wiley Periodicals, Inc. Head Neck 38: 1401-1406, 2016.

Autoimmunity against laminins

Laminins are ubiquitous constituents of the basement membranes with major architectural and functional role as supported by the fact that absence or mutations of laminins lead to either lethal or severely impairing phenotypes. Besides genetic defects, laminins are involved in a wide range of human diseases including cancer, infections, and inflammatory diseases, as well as autoimmune disorders. A growing body of evidence implicates several laminin chains as autoantigens in blistering skin diseases, collagenoses, vasculitis, or post-infectious autoimmunity. The current paper reviews the existing knowledge on autoimmunity against laminins referring to both experimental and clinical data, and on therapeutic implications of anti-laminin antibodies. Further investigation of relevant laminin epitopes in pathogenic autoimmunity would facilitate the development of appropriate diagnostic tools for thorough characterization of patients' antibody specificities and should decisively contribute to designing more specific therapeutic interventions.

Sulindac modulates secreted protein expression from LIM1215 colon carcinoma cells prior to apoptosis

Colorectal cancer (CRC) is a major cause of mortality in Western populations. Growing evidence from human and rodent studies indicate that nonsteroidal anti-inflammatory drugs (NSAIDs) cause regression of existing colon tumors and act as effective chemopreventive agents in sporadic colon tumor formation. Although much is known about the action of the NSAID sulindac, especially its role in inducing apoptosis, mechanisms underlying these effects is poorly understood. In previous secretome-based proteomic studies using 2D-DIGE/MS and cytokine arrays we identified over 150 proteins released from the CRC cell line LIM1215 whose expression levels were dysregulated by treatment with 1mM sulindac over 16h; many of these proteins are implicated in molecular and cellular functions such as cell proliferation, differentiation, adhesion, angiogenesis and apoptosis (Ji et al., Proteomics Clin. Appl. 2009, 3, 433-451). We have extended these studies and describe here an improved protein/peptide separation strategy that facilitated the identification of 987 proteins and peptides released from LIM1215 cells following 1mM sulindac treatment for 8h preceding the onset of apoptosis. This peptidome separation strategy involved fractional centrifugal ultrafiltration of concentrated cell culture media (CM) using nominal molecular weight membrane filters (NMWL 30K, 3K and 1K). Proteins isolated in the >30K and 3-30K fractions were electrophoretically separated by SDS-PAGE and endogenous peptides in the 1-3K membrane filter were fractioned by RP-HPLC; isolated proteins and peptides were identified by nanoLC-MS-MS. Collectively, our data show that LIM1215 cells treated with 1mM sulindac for 8h secrete decreased levels of proteins associated with extracellular matrix remodeling (e.g., collagens, perlecan, syndecans, filamins, dyneins, metalloproteinases and endopeptidases), cell adhesion (e.g., cadherins, integrins, laminins) and mucosal maintenance (e.g., glycoprotein 340 and mucins 5AC, 6, and 13). A salient finding of this study was the increased proteolysis of cell surface proteins following treatment with sulindac for 8h (40% higher than from untreated LIM1215 cells); several of these endogenous peptides contained C-terminal amino acids from transmembrane domains indicative of regulated intramembrane proteolysis (RIP). Taken together these results indicate that during the early-stage onset of sulindac-induced apoptosis (evidenced by increased annexin V binding, dephosphorylation of focal adhesion kinase (FAK), and cleavage of caspase-3), 1mM sulindac treatment of LIM1215 cells results in decreased expression of secreted proteins implicated in ECM remodeling, mucosal maintenance and cell-cell-adhesion. This article is part of a Special Issue entitled: An Updated Secretome.

Laminin-1 (LM-111) in preeclampsia and systemic lupus erythematosus

BACKGROUND

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by the production of antibodies. SLE has been associated with placental pathology, a finding that is also the determinant in preeclampsia (PE). Genetic evidence and serologic reports suggest laminin-1 (LM-111) as an immunogenic molecule and its polymorphic gene as a candidate gene for both disorders.

OBJECTIVE

To evaluate the association between LAMA1 (rs543355) and LAMC1 (rs20563) polymorphisms and the presence of SLE and PE as well as to determine serum levels of anti-LM-111 autoantibodies in the PE group.

METHODS

Group A: 169 women with PE and 172 healthy pregnant women. Group B: 204 women with SLE and 204 healthy women. Anti-LM-111 for group A was measured by ELISA and the genotyping was done by using a PCR system.

RESULTS

Group A: Levels of anti-LM-111 was similar in women with PE and the control group (p = 0.3). The allelic frequencies and genotypes did not show statistically significant differences for LAMA1 and LAMC1 polymorphisms. Group B: Significant differences between SLE patients and controls for rs543355 polymorphism were not observed. Nevertheless, LAMC1 rs20563 A-allele provided protection against the development of SLE (OR 0.73, 95%CI 0.55-0.96).

CONCLUSIONS

Serum levels of anti-LM-111 at the third trimester of gestation do not seem to have any direct relationship with the presence of PE, and the SNPs evaluated are not associated with the risk of developing this disorder. LAMC1 polymorphism could be a protective factor for SLE.

Extracellular remodelling during oncogenic Ras-induced epithelial-mesenchymal transition facilitates MDCK cell migration

Epithelial-mesenchymal transition (EMT) describes a process whereby immotile epithelial cells escape structural constraints imposed by cellular architecture and acquire a phenotype characteristic of migratory mesenchymal cells. Implicated in carcinoma progression and metastasis, EMT has been the focus of several recent proteomics-based studies aimed at identifying new molecular players. To gain insights into extracellular mediators associated with EMT, we conducted an extensive proteomic analysis of the secretome from MDCK cells following oncogenic Ras-induced EMT (21D1 cells). Using Orbitrap technology and a label-free quantitative approach, differential expression of several secreted modulators were revealed. Proteomic findings were further substantiated by mRNA transcript expression analysis with 71% concordance. MDCK cells undergoing Ras-induced EMT remodel the extracellular matrix (ECM) via diminished expression of basement membrane constituents (collagen type IV and laminin 5), up-regulation of extracellular proteases (MMP-1, kallikreins -6 and -7), and increased production and secretion of ECM constituents (SPARC, collagen type I, fibulins -1 and -3, biglycan, and decorin). Collectively, these findings suggest that hierarchical regulation of a subset of extracellular effectors may coordinate a biological response during EMT that enhances cell motility. Transient silencing of MMP-1 in 21D1 cells via siRNA-mediated knockdown attenuated cell migration. Many of the secretome proteins identified broaden our understanding of the EMT process.