Search Results (88)

Background/Objectives: Anti-p200 pemphigoid is a rare and likely underdiagnosed autoimmune blistering disorder. Laminin γ1 and laminin β4 have been implicated as potential target antigens in its pathogenesis. Recently, a novel indirect immunofluorescence assay targeting anti-laminin β4 antibodies has been developed, demonstrating high sensitivity and specificity, and offering a valuable tool for improved diagnosis. Methods: Of the 451 patients, 21 were selected for further laboratory analysis based on medical records. Sera from 10 patients, which showed a positive direct immunofluorescence (DIF) result and negative results in multiplex enzyme-linked immunosorbent assays (ELISAs) and/or mosaic six-parameter indirect immunofluorescence (IIF) for various autoimmune bullous diseases, were tested for the presence of anti-laminin β4 antibodies. Additionally, sera from 11 patients with positive DIF and positive ELISA for antibodies against BP180 and/or BP230 were analyzed. Results: Among the 10 patients with positive DIF and negative ELISA and/or mosaic six-parameter IIF, 6 sera were positive for anti-laminin β4 antibodies. These patients presented with atypical clinical features. In contrast, all 11 sera from patients with both positive DIF and positive ELISA for BP180 and/or BP230 were negative for anti-laminin β4 antibodies. Conclusions: In patients with a positive DIF result but negative ELISA and/or mosaic six-parameter IIF findings, testing for anti-laminin β4 antibodies should be considered. Furthermore, in cases presenting with atypical clinical features—such as acral distribution of lesions, intense pruritus, or erythematous–edematous plaques—the possibility of anti-p200 pemphigoid should be included in the differential diagnosis. Full article

Skin aging is characterized by compromised epidermal homeostasis and dermo-epidermal junction (DEJ) integrity, resulting in reduced stem cell potential and impaired tissue regeneration. This study investigated the effects of Andrographis paniculata extract (APE) on keratinocyte stem cells (KSCs) and DEJ composition in human skin. Using human skin explants and cell culture models, we demonstrated that APE treatment enhances DEJ composition by increasing Collagen IV and Laminin production while decreasing MMP-9 expression, without altering epidermal structure or differentiation. In the same model, APE preserved stemness potential by upregulating markers related to niche components (collagen XVII and β1-integrin), proliferation (Ki-67 and KRT15), and stem cell capacity (Survivin and LRIG1). In vitro studies revealed that APE selectively stimulated KSC proliferation without affecting transit amplifying cells and promoted Collagen IV and Laminin secretion, particularly in KSCs. Furthermore, in a co-culture model simulating a compromised DEJ (UVB-induced), APE increased Laminin production in KSCs, suggesting a protective effect against photo-damage. These findings indicate that APE enhances DEJ composition and preserves stem cell potential, highlighting its promise as a candidate for skin anti-aging strategies targeting stem cell maintenance and extracellular matrix stability to promote skin regeneration and repair. Full article

Inherited epidermolysis bullosa (EB) is a heterogeneous clinical entity that includes over 30 phenotypically and/or genotypically distinct inherited disorders, characterized by mechanical skin fragility and bullae formation. Junctional EB (JEB) is an autosomal recessive disease characterized by an intermediated cleavage level within the skin layers, commonly at the “lamina lucida”. Laryngo-onycho-cutaneous syndrome (LOC) is an extremely rare variant of JEB, characterized by granulation tissue formation in specific body sites (skin, larynx, and nails). Although most cases of JEB are caused by pathogenic variants occurring in the genes encoding for classical components of the lamina lucida, such as laminin 332 (LAMA3, LAMB3, LAMC2), integrin α6β4 (ITGA6, ITGB4), and collagen XVII (COL17A1), other variants have also been described. We report the case of a 4-month-old male infant who presented with recurrent bullous and erosive lesions from the first month of life. At the first dermatological evaluation, the patient was agitated and exhibited hoarse breathing, a clinical sign suggestive of laryngeal involvement. Multiple polygonal skin erosions were observed on the cheeks, along with similar isolated, roundish lesions on the scalp and legs. Notably, nail dystrophy and near-complete anonychia were evident on the left first and fifth toes. Due to the coexistence of skin erosions and nail dystrophy in such a young infant, a congenital bullous disorder was suspected, prompting molecular analysis of all potentially involved genes. In the patient’s DNA, clinical exome sequencing (CES) identified a pathogenic variant, apparently in homozygosity, in the exon 1 of the LAMA3 gene (18q11.2; NM_000227.6): c.47G > A;p.Trp16*. The presence of this variant was confirmed, in heterozygosity, in the genomic DNA of the patient’s mother, while it was absent in the father’s DNA. Subsequently, trio-based SNP array analysis was performed, revealing a paternally derived pathogenic microdeletion encompassing the LAMA3 locus (18q11.2). To our knowledge, this is the first reported case of JEB with a LOC-like phenotype caused by a maternally inherited monoallelic nonsense mutation in LAMA3, unmasked by an almost complete deletion of the paternal allele. The combined use of exome sequencing and SNP array is proving essential for elucidating autosomal recessive diseases with a discordant segregation. This is pivotal for providing accurate genetic counseling to parents regarding future pregnancies. Full article

The attachment of the oral epithelium to the abutment surface is crucial for the long-term success of dental implants. This study aimed to evaluate the attachment of human epithelial cells to anodized titanium surfaces. Anodized titanium discs were used as the experimental group, while machined titanium discs served as the control. Surface roughness and wettability were first measured for each group. Next, human epithelial cells were seeded onto each disc at a density of 4.0 × 10⁴ cells/cm² and evaluated 3, 6, and 24 h later for cell proliferation, as well as mRNA expression and protein levels of laminin and integrin β₄. Surface roughness was comparable between the two groups; however, wettability was significantly higher in the experimental group. Cell proliferation increased over time in both groups and showed no significant difference. Notably, the expression levels of both laminin and integrin β₄ were significantly higher in the experimental group at 24 h. Furthermore, protein localization of laminin and integrin β₄ was observed along the cell margins on the anodized surface. These findings suggest that anodization enhances epithelial cell attachment by promoting the expression and peripheral organization of key adhesion molecules. Full article

The junctional epithelium, which lines the inner gingival surface, seals the gingival sulcus to block the infiltration of food debris and pathogens. The junctional epithelium is derived from the reduced enamel epithelium, consisting of late developmental stage ameloblasts and accessory cells. No prior studies have investigated whether defective ameloblast differentiation or enamel matrix formation affects junctional epithelium anatomy or function. Here, we examined the junctional epithelium in mice exhibiting amelogenesis imperfecta due to loss-of-function mutations in the major enamel matrix protein amelogenin (Amelx^−/−) or the critical enamel matrix protease KLK4 (Klk4^−/−). Histological analyses demonstrated altered morphology and cell layer thickness of the junctional epithelium in Amelx^−/− and Klk4^−/− mice as compared to wt. Immunohistochemistry revealed reduced ODAM, laminin 5, and integrin α6, all of which are critical for the adhesion of the junctional epithelium to the enamel in Amelx^−/− and Klk4^−/− mice. Furthermore, we observed altered cell–cell adhesion and increased permeability of Dextran-GFP through the mutants’ junctional epithelium, indicating defective barrier function. Reduced β-catenin and Ki67 at the base of the junctional epithelium in mutants suggest impaired mitotic activity and reduced capacity to replenish continuously desquamated epithelium. These findings highlight the essential role of normal amelogenesis in maintaining junctional epithelium homeostasis. Full article

Type 1 diabetes (T1D) is caused by autoimmune-mediated destruction of pancreatic β-cells, resulting in insulin deficiency. While islet transplantation presents a potential therapeutic approach, its clinical application is impeded by limited donor availability and the risk of immune rejection. This study proposes an innovative islet encapsulation strategy that utilizes decellularized porcine pancreatic extracellular matrix (pECM) as the sole biomaterial to engineer bioactive, immunoprotective microcapsules. Rat islets were encapsulated within pECM-based microcapsules using the electrospray technology and were compared to conventional alginate-based microcapsules in terms of viability, function, and response to hypoxic stress. The pECM microcapsules maintained a spherical morphology, demonstrating mechanical robustness, and preserving essential ECM components (collagen I/IV, laminin, fibronectin). Encapsulated islets exhibited sustained viability and superior insulin secretion over a two-week period compared to alginate controls. The expression of key β-cell transcription factors (PDX1, MAFA) and structural integrity were preserved. Under hypoxic conditions, pECM microcapsules significantly reduced islet apoptosis, improved structural retention, and promoted functional recovery, likely due to antioxidant and ECM-derived cues inherent to the pECM. In vivo transplantation in immunocompetent mice confirmed the biocompatibility of pECM microcapsules, with minimal immune responses, stable insulin/glucagon expression, and no adverse systemic effects. These findings position pECM-based microencapsulation as a promising strategy for creating immunoprotective, bioactive niches for xenogeneic islet transplantation, with the potential to overcome current limitations in cell-based diabetes therapy. Full article

Background: The role of extracellular matrix adhesion components in modulation of the treatment sensitivity of ovarian cancer (OC) cells is not well understood. Methods and Results: Analysis of ovarian cancer TCGA gene expression datasets revealed an inverse correlation between genes involved in cell-cycle progression and extracellular matrix interactions, including laminin-binding receptor integrin β4, a major component of extracellular matrix adhesion. Gene ontology analysis also showed that in patient populations with low ITGB4 expression, cell cycle-related programs were activated, while in populations with high expression of ITGB4, the activation of these cell cycle programs was lower. Suppression of proliferation with the CDK4/6 inhibitor Palbociclib stimulated integrin β4 expression and induced protection against Cisplatin in cells naturally expressing low levels of integrin β4. Additionally, ovarian cancer patient-derived organoids showed reduced Cisplatin sensitivity when pretreated with Palbociclib. Our data also showed that integrin β4 overexpression decreased ovarian cancer cell proliferation and at the same time, attenuated Cisplatin response. Conclusions: In summary, our investigations support the idea that integrin β4, and likely its matrix ligands, play critical roles in the regulation of cellular growth and the chemoresistance of ovarian cancer cells. Full article

The human laminin family is composed of five α, four β, and three γ chains. Laminins are heterotrimers of α, β, and γ chains. Laminins play critical roles during organogenesis, mostly as basement membrane components. The expression of all and the localization of most laminin chains were characterized in mouse developing teeth. Primary laminin isoforms in basement membranes along the inner enamel epithelium before the secretory stage and outside of the outer enamel epithelium were laminins 111 (α1β1γ1) and 511. The mouse laminin α3 chain has two variants, α3A and α3B. Although a basement membrane structure is absent, laminin 3A32 was localized along the secretory surface of the secretory stage ameloblast Tomes’ processes. Laminin 3A32 was localized along the atypical basement membrane of maturation stage ameloblasts and the specialized basement membrane of junctional epithelium facing the enamel surface. The endothelial basement membrane in the dental papilla and outside of the enamel organ contained laminins 411 and 511. Laminin 332 was detected in the extracellular matrix but not the basement membrane of the apical loop. Laminin 111 was localized in the extracellular matrix of the apical dental papilla without forming a visible basement membrane. These findings suggest the multifaceted functions of laminins in tooth development and set the foundation for functional investigations. Full article

Studies have consistently shown that long-wave ultraviolet A (UVA) radiation triggers skin photoaging, which is evident as reduced elasticity, a loss of firmness, and signs of aging. There is an urgent need to investigate photoaging mechanisms to devise protective strategies against UVA. The present study aimed to explore the effects of recombinant type XVII collagen on UVA-induced skin aging and uncover its molecular mechanisms, thereby laying a solid theoretical foundation for precise treatments and prevention. We therefore modeled photoaging damage in HaCaT cells and evaluated collagen-related protein and gene expression levels via western blot analysis and real-time quantitative polymerase chain reaction analysis. Immunofluorescent staining was also used to assess collagen secretion and basement membrane protein expression. Recombinant type XVII collagen significantly boosted type IV and type XVII collagen, laminin alpha 5, and integrin β1 production, thus counteracting UVA-induced collagen decline. The polymerase chain reaction analysis revealed matrix metalloproteinase (MMP) downregulation and tissue inhibitor of metalloproteinase (TIMP) upregulation. Modulating the transforming growth factor (TGF)-β/Smad and epidermal growth factor receptor (EGFR)/mitogen-activated protein kinase (MAPK)/activator protein-1 (AP-1) pathways suppressed photoaging. Together, our findings suggest that recombinant type XVII collagen ameliorates UVA-induced damage by reversing MMP and TIMP gene expression, thereby preventing collagen degradation and enhancing basement membrane secretion. These results offer a theoretical basis for potent anti-photoaging products, thus paving the way for innovative solutions against UVA-induced skin aging. Full article

Periodontitis is accompanied by inflammation that causes dysregulation of the Wnt/β-catenin and TGF-β signaling pathways. This leads to a violation of the homeostasis of periodontal tissues. Components of the extracellular matrix (ECM) are an important part of biomaterials used for the repair of periodontal tissue. The purpose of this study was to evaluate the components of the effect of ECM (hyaluronic acid (HA), fibronectin (Fn), and laminin (Lam)) on the osteogenic and odontogenic differentiation of periodontal ligament stem cells (PDLSCs) in the collagen I hydrogel under conditions of disruption of the Wnt/β-catenin and TGF-β signaling pathways. The study showed that the addition of components of the ECM restored the expression of odontogenic markers in PDLSCs, which was absent during inhibition of the canonical Wnt signaling pathway, and their multidirectional effect on the secretion of transforming growth factor-β1 (TGF-β1) and bone morphogenetic protein 2 (BMP-2). Fn and Lam suppressed the expression of odontogenic markers in PDLSCs against the background of inhibition of the TGF-β signaling pathway. The addition of HA under the conditions of the TGF-β signaling pathway improved BMP-2 secretion, preserving odontogenic differentiation. Thus, our results demonstrated that disruption of the Wnt/β-catenin and TGF-β signaling pathways causes disorders in the differentiation of PDLSCs, preventing the regeneration of periodontal tissues. This should be taken into account when developing multicomponent scaffolds that recapitulate the ECM microenvironment at endogenic regeneration of the periodontium. Inclusion of hyaluronic acid as one of these components may enhance the therapeutic effect of such biomaterials. Full article

Background: Excessive accumulation of glomerular extracellular matrix (ECM) is a key factor in the development and progression of diabetic nephropathy (DN). As kidney dysfunction has been reported in normoalbuminuric patients, identifying novel diagnostic and prognostic markers is essential for the prevention and treatment of DN. Methods: Urinary excretion of neutrophil gelatinase-associated lipocalin (NGAL) and ECM-related glycoproteins, i.e., fibronectin (FN) and laminin (LN), was measured in obese patients with newly diagnosed type 2 diabetes mellitus (T2DM) before and after 6 months of metformin therapy. Results: Baseline NGAL (1.27 (0.80–2.36) ng/mg Cr), FN (11.19 (5.31–21.56) ng/mg Cr) and LN (123.17 (54.56–419.28) pg/mg Cr) levels did not significantly differ between T2DM patients and controls (1.95 (1.09–2.97) ng/mg Cr, 11.94 (7.78–18.01) ng/mg Cr and 157.85 (83.75–326.40) pg/mg Cr, respectively). In multivariate regression analysis, the body mass index was identified as the only significant predictor influencing urinary NGAL and FN levels at baseline, with β = 0.249, p = 0.005 and β = 1.068, p = 0.010, respectively. Metformin treatment significantly increased urinary levels of both ECM proteins, i.e., FN (18.48 (11.64–32.46) ng/mg Cr) and LN (179.51 (106.22–414.68) pg/mg Cr), without any effect on NGAL levels (1.44 (0.81–2.72) ng/mg Cr). FN and LN were positively associated with NGAL both before (r = 0.709 and r = 0.646, both p < 0.001, respectively) and after (r = 0.594 and r = 0.479, both p < 0.001, respectively) therapy. No correlations were found between NGAL, FN, LN, and albuminuria. However, NGAL was positively correlated with the albumin/creatinine ratio (ACR) both before (r = 0.323, p < 0.05) and after (r = 0.287, p < 0.05) therapy, and negatively with estimated glomerular filtration rate (eGFR) in pre-treatment diabetics (r = −0.290, p < 0.05). FN and LN were also correlated with ACR (r = 0.384, p < 0.01 and r = 0.470, p < 0.001), although the association for LN was limited to untreated patients (r = 0.422, p < 0.01). Conclusions: Our results suggest that metformin has a beneficial effect on ECM turnover with a significant increase in urinary excretion of non-collagenous markers of glomerular injury, i.e., FN and LN. Additionally, ECM-related markers may serve as useful tools for monitoring early renal injury in obese diabetic patients. Full article

Collagen and its peptides exhibit remarkable antioxidant activity, superior biocompatibility, and water solubility, making them a significant research focus in skin care. Hence, the recombinant humanized collagen types I, III, and XVII complexed with niacinamide were developed to address damage in human foreskin fibroblasts (HFF-1) caused by ultraviolet radiation and to evaluate basement membrane proteins in a rat skin model. The Cell Counting Kit-8 (CCK-8) assay showed that higher concentrations of the complex increased the survival of damaged cells by approximately 10% and 22%, respectively, compared to the normal group after 16 and 48 h of treatment. Further biochemical analyses using ELISA and immunofluorescence (IF) confirmed that the complex enhanced the expression of collagen type IV, laminin, P63, and transforming growth factor-β (TGF-β) in the damaged cells. Additionally, the complex boosted the activity of the basement membrane in rat skin and stimulated the secretion of integrin, laminin, and perlecan. Overall, the recombinant humanized collagen complex effectively reinforced the skin’s basement membrane. Full article

Background/Objectives: The progression of colorectal cancer through clinically and histopathologically well-defined stages is driven by specific mutations that activate oncogenes or inactivate tumor-suppressor genes. In addition, pre-cancerous/cancer cells respond to cues from the tissue microenvironment that support tumorigenesis and progression, many of which are transmitted through integrin receptors for the extracellular matrix. Integrin α3β1 has pro-tumorigenic/pro-metastatic roles in many cancers, but it also has suppressive roles in some cancers or at specific stages of progression, indicating that its potential value as a therapeutic target cannot be extrapolated across cancer types or stages. In this study, we investigated roles for α3β1 in colorectal cancer using cellular and genetic models that represent different stages. Methods: We generated mice with colon-specific α3 knockout in a tamoxifen-inducible model of KRAS-mutated colorectal cancer to assess the effects of α3β1 ablation on early dysplasia. We also used siRNA to suppress α3β1 in human colorectal cancer cells, then assessed effects on motility and invasion in vitro. Results: Genetic deletion of α3β1 in the colon did not alter dysplasia in mice predisposed to KRAS-mutated colorectal cancer, and it was accompanied by an increase in the colocalization of α6 integrin with laminin-332 (a matrix ligand for both integrins), suggesting functional compensation. However, suppression of α3β1 caused an approximately 40% to 60% reduction in the motility/invasion of human colorectal cancer cells. Conclusions: Our findings that α3β1 is not required for pre-cancerous dysplasia but promotes colorectal cancer cell motility/invasion indicate an important role for pro-migratory functions of this integrin at later stages of progression when cells invade from the primary tumor, suggesting that strategies to target α3β1 in colorectal cancer should be aimed at distinct stages of disease progression. Full article

Viperid snake venoms are notably abundant in metalloproteinases (proteins) (SVMPs), which are primarily responsible for inducing hemorrhage and disrupting the hemostatic process and tissue integrity in envenomed victims. In this study, barnettlysin-III (Bar-III), a hemorrhagic P-III SVMP, was purified from the venom of the Peruvian snake Bothrops barnetti. Bar-III has a molecular mass of approximately 50 kDa and is a glycosylation-dependent functional metalloproteinase. Some biochemical properties of Bar-III, including the full amino acid sequence deduced from its cDNA, are reported. Its enzymatic activity is increased by Ca²⁺ ions and inhibited by an excess of Zn²⁺. Synthetic metalloproteinase inhibitors and EDTA also inhibit its proteolytic action. Bar-III degrades several plasma and ECM proteins, including fibrin(ogen), fibronectin, laminin, and nidogen. Platelets play a key role in hemostasis and thrombosis and in other biological process, such as inflammation and immunity, and platelet activation is driven by the platelet signaling receptors, glycoprotein (GP)Ib-IX-V, which binds vWF, and GPVI, which binds collagen. Moreover, Bar-III inhibits vWF- and convulxin-induced platelet aggregation in human washed platelets by cleaving the recombinant A1 domain of vWF and GPVI into a soluble ectodomain fraction of ~55 kDa (sGPVI). Bar-III does not reduce the viability of cultured endothelial cells; however, it interferes with the adhesion of these cells to fibronectin, vitronectin, and RGD peptides, as well as their migration profile. Bar-III binds specifically to the surface of these cells, and part of this interaction involves α5β1 integrin receptors. These results contribute to a better comprehension of the pathophysiology of snakebite accidents/incidents and could be used as a tool to explore novel and safer anti-venom therapeutics. Full article

Background: α-dystroglycanopathies are congenital muscular dystrophies in which genetic mutations cause the decrease or absence of a unique and complex O-linked glycan called matriglycan. This hypoglycosylation of O-linked matriglycan on the α-dystroglycan (α-DG) protein subunit abolishes or reduces the protein binding to extracellular ligands such as laminins in skeletal muscles, leading to compromised survival of muscle cells after contraction. Methods: Surrogate molecular linkers reconnecting laminin-211 and the dystroglycan β-subunit through bispecific antibodies can be engineered to improve muscle function in the α-dystroglycanopathies. This study reports the metabolic engineering of a novel glycofusion bispecific (GBi) antibody that fuses the mucin-like domain of the α-DG to the light chain of an anti-β-DG subunit antibody. Results: Transient HEK production with the co-transfection of LARGE1, the glycoenzyme responsible for the matriglycan modification, produced the GBi antibody only with a light matriglycan modification and a weak laminin-211 binding activity. However, when a sugar feed mixture of uridine, galactose, and manganese ion (Mn²⁺) was added to the culture medium, the GBi antibody produced exhibited a dramatically enhanced matriglycan modification and a much stronger laminin-binding activity. Conclusions: Further investigation has revealed that Mn²⁺ in the sugar feeds played a critical role in increasing the matriglycan modification of the GBi antibody, key for the function of the resulting bispecific antibody. Full article