Polymerizing laminins in development, health, and disease.

Polymerizing laminins are multi-domain basement membrane (BM) glycoproteins that self-assemble into cell-anchored planar lattices to establish the initial BM scaffold. Nidogens, collagen-IV and proteoglycans then bind to the scaffold at different domain loci to create a mature BM. The LN domains of adjacent laminins bind to each other to form a polymer node, while the LG domains attach to cytoskeletal-anchoring integrins and dystroglycan, as well as to sulfatides and heparan sulfates. The polymer node, the repeating unit of the polymer scaffold, is organized into a near-symmetrical triskelion. The structure, recently solved by cryo-electron microscopy in combination with AlphaFold2 modeling and biochemical studies, reveals how the LN surface residues interact with each other and how mutations cause failures of self-assembly in an emerging group of diseases, the LN-lamininopathies, that include LAMA2-related dystrophy and Pierson syndrome.

Genetic Disorders of the Extracellular Matrix: From Cell and Gene Therapy to Future Applications in Regenerative Medicine.

Metazoans have evolved to produce various types of extracellular matrix (ECM) that provide structural support, cell adhesion, cell-cell communication, and regulated exposure to external cues. Epithelial cells produce and adhere to a specialized sheet-like ECM, the basement membrane, that is critical for cellular homeostasis and tissue integrity. Mesenchymal cells, such as chondrocytes in cartilaginous tissues and keratocytes in the corneal stroma, produce a pericellular matrix that presents optimal levels of growth factors, cytokines, chemokines, and nutrients to the cell and regulates mechanosensory signals through specific cytoskeletal and cell surface receptor interactions. Here, we discuss laminins, collagen types IV and VII, and perlecan, which are major components of these two types of ECM. We examinegenetic defects in these components that cause basement membrane pathologies such as epidermolysis bullosa, Alport syndrome, rare pericellular matrix-related chondrodysplasias, and corneal keratoconus and discuss recent advances in cell and gene therapies being developed for some of these disorders.

Defective perlecan-associated basement membrane regeneration and altered modulation of transforming growth factor beta in corneal fibrosis.

In the cornea, the epithelial basement membrane (EBM) and corneal endothelial Descemet's basement membrane (DBM) critically regulate the localization, availability and, therefore, the functions of transforming growth factor (TGF)ß1, TGFß2, and platelet-derived growth factors (PDGF) that modulate myofibroblast development. Defective regeneration of the EBM, and notably diminished perlecan incorporation, occurs via several mechanisms and results in excessive and prolonged penetration of pro-fibrotic growth factors into the stroma. These growth factors drive mature myofibroblast development from both corneal fibroblasts and bone marrow-derived fibrocytes, and then the persistence of these myofibroblasts and the disordered collagens and other matrix materials they produce to generate stromal scarring fibrosis. Corneal stromal fibrosis often resolves completely if the inciting factor is removed and the BM regenerates. Similar defects in BM regeneration are likely associated with the development of fibrosis in other organs where perlecan has a critical role in the modulation of signaling by TGFß1 and TGFß2. Other BM components, such as collagen type IV and collagen type XIII, are also critical regulators of TGF beta (and other growth factors) in the cornea and other organs. After injury, BM components are dynamically secreted and assembled through the cooperation of neighboring cells-for example, the epithelial cells and keratocytes for the corneal EBM and corneal endothelial cells and keratocytes for the corneal DBM. One of the most critical functions of these reassembled BMs in all organs is to modulate the pro-fibrotic effects of TGFßs, PDGFs and other growth factors between tissues that comprise the organ.

[Research Progress on the Role of Laminin Subunit Alpha 4 in Diseases].

Laminin subunit alpha 4 (LAMA4),a member of the laminin family,is present in the intercellular matrix of adult tissues as a major component of basement membrane.LAMA4 is involved in the adhesion of cells and can bind to corresponding integrins to activate relevant signaling pathways,playing an essential role in the growth,proliferation,and migration of cells.It has been demonstrated that LAMA4 is associated with the occurrence and development of a variety of diseases including tumors,and the expression of LAMA4 can be used as a biomarker of tumor diagnosis and prognosis.This paper summarizes the current research progress in LAMA4 with the focus on the relationship between LAMA4 and diseases,especially tumor,with a view to provide new directions for the future research.

Cell Adhesion Molecules Affected by Ionizing Radiation and Estrogen in an Experimental Breast Cancer Model.

Cancer develops in a multi-step process where environmental carcinogenic exposure is a primary etiological component, and where cell-cell communication governs the biological activities of tissues. Identifying the molecular genes that regulate this process is essential to targeting metastatic breast cancer. Ionizing radiation can modify and damage DNA, RNA, and cell membrane components such as lipids and proteins by direct ionization. Comparing differential gene expression can help to determine the effect of radiation and estrogens on cell adhesion. An in vitro experimental breast cancer model was developed by exposure of the immortalized human breast epithelial cell line MCF-10F to low doses of high linear energy transfer α particle radiation and subsequent growth in the presence of 17ß-estradiol. The MCF-10F cell line was analyzed in different stages of transformation that showed gradual phenotypic changes including altered morphology, increase in cell proliferation relative to the control, anchorage-independent growth, and invasive capability before becoming tumorigenic in nude mice. This model was used to determine genes associated with cell adhesion and communication such as E-cadherin, the desmocollin 3, the gap junction protein alpha 1, the Integrin alpha 6, the Integrin beta 6, the Keratin 14, Keratin 16, Keratin 17, Keratin 6B, and the laminin beta 3. Results indicated that most genes had greater expression in the tumorigenic cell line Tumor2 derived from the athymic animal than the Alpha3, a non-tumorigenic cell line exposed only to radiation, indicating that altered expression levels of adhesion molecules depended on estrogen. There is a significant need for experimental model systems that facilitate the study of cell plasticity to assess the importance of estrogens in modulating the biology of cancer cells.

Angiotropism, pericytic mimicry and extravascular migratory metastasis: an embryogenesis-derived program of tumor spread.

Intravascular dissemination of tumor cells is the accepted mechanism of cancer metastasis. However, the phenomenon of angiotropism, pericyte mimicry (PM), and extravascular migratory metastasis (EVMM) has questioned the concept that tumor cells metastasize exclusively via circulation within vascular channels. This new paradigm of cancer spread and metastasis suggests that metastatic cells employ embryonic mechanisms for attachment to the abluminal surfaces of blood vessels (angiotropism) and spread via continuous migration, competing with and replacing pericytes, i.e., pericyte mimicry (PM). This is an entirely extravascular phenomenon (i.e., extravascular migratory metastasis or EVMM) without entry (intravasation) into vascular channels. PM and EVMM have mainly been studied in melanoma but also occur in other cancer types. PM and EVMM appear to be a reversion to an embryogenesis-derived program. There are many analogies between embryogenesis and cancer progression, including the important role of laminins, epithelial-mesenchymal transition, and the re-activation of embryonic signals by cancer cells. Furthermore, there is no circulation of blood during the first trimester of embryogenesis, despite the fact that there is extensive migration of cells to distant sites and formation of organs and tissues during this period. Embryonic migration therefore is a continuous extravascular migration as are PM and EVMM, supporting the concept that these embryonic migratory events appear to recur abnormally during the metastatic process. Finally, the perivascular location of tumor cells intrinsically links PM to vascular co-option. Taken together, these two new paradigms may greatly influence the development of new effective therapeutics for metastasis. In particular, targeting embryonic factors linked to migration that are detected during cancer metastasis may be particularly relevant to PM/EVMM.

Corneal epithelial basement membrane: Structure, function and regeneration.

Basement membranes are highly specialized extracellular matrices. More than providing scaffolds, basement membranes are recognized as dynamic and versatile structures that modulate cellular responses to regulate tissue development, function, and repair. Increasing evidence suggests that, in addition to providing structural support to adjacent cells, basement membranes serve as reservoirs and modulators of growth factors that direct and fine-tune cellular functions. Since the corneal stroma is avascular and has a relatively low keratocyte density, it's likely that the corneal BM is different in composition from the BMs in other tissues. BMs are composed of a diverse assemblage of extracellular molecules, some of which are likely specific to the tissue where they function; but in general they are composed of four primary components-collagens, laminins, heparan sulfate proteoglycans, and nidogens-in addition to other components such as thrombospondin-1, matrilin-2, and matrilin-4 and fibronectin. Severe injuries to the cornea, including infection, surgery, and trauma, may trigger the development of myofibroblasts and fibrosis in the normally transparent connective tissue stroma. Ultrastructural studies have demonstrated that defective epithelial basement membrane (EBM) regeneration after injury to the cornea underlies the development of myofibroblasts from both bone marrow- and keratocyte-derived precursor cells. Defective EBM permits epithelium-derived and tear-derived transforming growth factor beta (TGF-ß), platelet-derived growth factor (PDGF), and possibly other modulators, to penetrate the stroma at sustained levels necessary to drive the development and persistence of vimentin + alpha-smooth muscle actin + desmin+ (V + A + D+) mature myofibroblasts. A recent discovery that has contributed to our understanding of haze development is that keratocytes and corneal fibroblasts produce critical EBM components, such as nidogen-1, nidogen-2 and perlecan, that are essential for complete regeneration of a normal EBM once laminin secreted by epithelial cells self-polymerizes into a nascent EBM. Mature myofibroblasts that become established in the anterior stroma are a barrier to keratocyte/corneal fibroblast contributions to the nascent EBM. These myofibroblasts, and the opacity they produce, often persist for months or years after the injury. Transparency is subsequently restored if the EBM is fully regenerated, myofibroblasts are deprived of TGF-ß and undergo apoptosis, and keratocytes reoccupy the anterior stroma and reabsorb the disordered extracellular matrix.

Connective Tissue and Age-Related Diseases.

We begin this chapter by describing normal characteristics of several pertinent connective tissue components, and some of the basic changes they undergo with ageing. These alterations are not necessarily tied to any specific disease or disorders, but rather an essential part of the normal ageing process. The general features of age-induced changes, such as skin wrinkles, in selected organs with high content of connective or soft tissues are discussed in the next part of the chapter. This is followed by a section dealing with age-related changes in specific diseases that fall into at least two categories. The first category encompasses common diseases with high prevalence among mostly ageing populations where both genetic and environmental factors play roles. They include but may not be limited to atherosclerosis and coronary heart disease, type II diabetes, osteopenia and osteoporosis, osteoarthritis, tendon dysfunction and injury, age-related disorders of spine and joints. Disorders where genetics plays the primary role in pathogenesis and progression include certain types of progeria, such as Werner syndrome and Hutchinson-Gilford progeria belong to the second category discussed in this chapter. These disorders are characterized by accelerated signs and symptoms of ageing. Other hereditary diseases or syndromes that arise from mutations of genes encoding for components of connective tissue and are less common than diseases included in the first group will be discussed briefly as well, though they may not be directly associated with ageing, but their connective tissue undergoes some changes compatible with ageing. Marfan and Ehlers-Danlos syndromes are primary examples of such disorders. We will probe the role of specific components of connective tissue and extracellular matrix if not in each of the diseases, then at least in the main representatives of these disorders.

Culture of human ovarian tissue in xeno-free conditions using laminin components of the human ovarian extracellular matrix.

PURPOSE: Our purpose was to identify human ovarian extracellular matrix (ECM) components that would support in vitro culture of human ovarian tissue and be compatible with possible future clinical applications. We characterized ovarian expression of laminins and selected three laminin tripeptides for culture experiments to be compared with Matrigel, an undefined and animal-based mixture of ECM components. METHODS: Expression of the 12 laminin genes was determined on transcript and protein levels using cortical tissue samples (n = 6), commercial ovary RNA (n = 1), follicular fluid granulosa cells (n = 20), and single-cell RNA-sequencing data. Laminin 221 (LN221), LN521, LN511, and their mixture were chosen for a 7-day culture experiment along with Matrigel using tissue from 17 patients. At the end of the culture, follicles were evaluated by scoring and counting from serial tissue sections, apoptosis measured using in situ TUNEL assay, proliferation by Ki67 staining, and endocrine function by quantifying steroids in culture media using UPLC-MS/MS. RESULTS: Approximately half of the cells in ovarian cortex expressed at least one laminin gene. The overall most expressed laminin α-chains were LAMA2 and LAMA5, ß-chains LAMB1 and LAMB2, and γ-chain LAMC1. In culture experiments, LN221 enhanced follicular survival compared with Matrigel (p < 0.001), whereas tissue cultured on LN521 had higher proportion of secondary follicles (p < 0.001). LN511 and mixture of laminins did not support the cultures leading to lower follicle densities and higher apoptosis. All cultures produced steroids and contained proliferating cells. CONCLUSIONS: LN221 and LN521 show promise in providing xeno-free growth substrates for human ovarian tissue cultures, which may help in further development of folliculogenesis in vitro for clinical practices. The system could also be used for identification of adverse effects of chemicals in ovaries.

Laminins and cancer stem cells: Partners in crime?

As one of the predominant protein families within the extracellular matrix both structurally and functionally, laminins have been shown to be heavily involved in tumor progression and drug resistance. Laminins participate in key cellular events for tumor angiogenesis, cell invasion and metastasis development, including the regulation of epithelial-mesenchymal transition and basement membrane remodeling, which are tightly associated with the phenotypic characteristics of stem-like cells, particularly in the context of cancer. In addition, a great deal of studies and reports has highlighted the critical roles of laminins in modulating stem cell phenotype and differentiation, as part of the stem cell niche. Stemming from these discoveries a growing body of literature suggests that laminins may act as regulators of cancer stem cells, a tumor cell subpopulation that plays an instrumental role in long-term cancer maintenance, metastasis development and therapeutic resistance. The accumulating evidence in this emerging research area suggests that laminins represent potential therapeutic targets for anti-cancer treatments against cancer stem cells, and that they may be used as predictive and prognostic markers to inform clinical management and improve patient survival.

[Laminins in Metastatic Cancer].

Laminins are a family of extracellular heterotrimeric glycoproteins that are the main structural component of basement membranes (BMs), perform a barrier function, and are important for adhesion, differentiation, migration, and resistance to apoptosis of various cells, including cancer cells. The review summarizes the current knowledge of how laminins produced by cancer and normal cells influence the key stages of carcinogenesis. Laminin 332 (LN-332) and LN-111 enhance proliferation of certain cancer cells and increase the tumour growth. LN-111 increases resistance to apoptosis, induces differentiation, and inhibits the epithelial-mesenchymal transition (EMT) of cancer cells. LN-332 is associated with higher adhesion and higher migration potential of cancer cells. LN-411 and LN-421 significantly increase motility of cancer cells. LN-332 and LN-511 facilitate cell-cell adhesion and affect the efficacy of cell-cell interactions. The laminin chains α4 and α5 are important for the development and function of blood and lymphatic vessels. The expression ratio of the α4 and α5 laminin chains defines the BM permeability to leukocytes and, presumably, cancer cells in blood and lymphatic vessels. Interactions between LN-511 and α2-containing laminins enhance self-renewal and survival of circulating cancer stem cells. Moreover, laminins are involved in the formation of premetastatic niches and new colonies. Endogenous expression of the α4 laminin chain stimulates proliferation of individualised circulating cancer cells in vitro and in vivo and facilitates micrometastasis.

Synaptic Homeostasis and Its Immunological Disturbance in Neuromuscular Junction Disorders.

In the neuromuscular junction, postsynaptic nicotinic acetylcholine receptor (nAChR) clustering, trans-synaptic communication and synaptic stabilization are modulated by the molecular mechanisms underlying synaptic plasticity. The synaptic functions are based presynaptically on the active zone architecture, synaptic vesicle proteins, Ca2+ channels and synaptic vesicle recycling. Postsynaptically, they are based on rapsyn-anchored nAChR clusters, localized sensitivity to ACh, and synaptic stabilization via linkage to the extracellular matrix so as to be precisely opposed to the nerve terminal. Focusing on neural agrin, Wnts, muscle-specific tyrosine kinase (a mediator of agrin and Wnts signalings and regulator of trans-synaptic communication), low-density lipoprotein receptor-related protein 4 (the receptor of agrin and Wnts and participant in retrograde signaling), laminin-network (including muscle-derived agrin), extracellular matrix proteins (participating in the synaptic stabilization) and presynaptic receptors (including muscarinic and adenosine receptors), we review the functional structures of the synapse by making reference to immunological pathogenecities in postsynaptic disease, myasthenia gravis. The synapse-related proteins including cortactin, coronin-6, caveolin-3, doublecortin, R-spondin 2, amyloid precursor family proteins, glia cell-derived neurotrophic factor and neurexins are also discussed in terms of their possible contribution to efficient synaptic transmission at the neuromuscular junction.

Systematic proteomics analysis revealed different expression of laminin interaction proteins in breast cancer: lower in luminal subtype and higher in claudin-low subtype.

Background: Breast cancer is a major public health concern. Proteomics enables identification of proteins with aberrant properties. Here, we identified proteins with abnormal expression levels in breast cancer tissues and systematically analyzed and validated the data to locate potential diagnostic and therapeutic targets. Methods: Protein expression level in breast cancer tissues and para-carcinoma tissues were detected by Isobaric Tags for Relative and Absolute Quantification (iTRAQ) technology and further screened through Gene Expression Profiling Interactive Analysis (GEPIA) database. Cellular components, protein domain and Reactome pathway analysis were performed to screen functional targets. Abnormal expression levels of functional targets were validated by Oncomine database, quantitative real time polymerase chain reaction (qRT-PCR) and proteomics detection. Protein correlation analysis was performed to explain the abnormal expression levels of potential targets in breast cancer. Results: Overall, 207 and 207 proteins were up- and down-regulated, respectively, in breast cancer tissues, and approximately 50% were also detected in the GEPIA database. The overlapping proteins were mainly extracellular proteins containing epidermal growth factor-like domain in leukocyte adhesion molecule (EGF-Lam) domain and enriched in laminin interaction pathway. Moreover, the downregulated laminin interaction proteins could be functional targets, which were also validated through Oncomine-Richardson and Oncomine-Curtis database. However, the lower expression level of laminin interaction proteins only fit for luminal breast cancer cells with no or low metastasis ability because the proteins achieved higher expression level in more invasive claudin-low breast cancer cells. In addition, when compared with corresponding in situ carcinoma tissues, above-mentioned proteins also showed higher expression levels in invasive carcinoma tissues. Finally, we have revealed the negative correlation between the laminin interaction proteins and the claudins. Conclusions: The laminin interaction protein, especially for laminins with ß1 and γ1 subunits and their integrin receptors with α1 and α6 subunits, showed lower expression levels in luminal breast cancer with no or lower metastatic ability, but showed higher expression levels in claudin-low breast cancer with higher metastatic ability; and their higher expression could be related to the low claudin expression.

Bioactive Hydrogels Inspired by Laminin: An Emerging Biomaterial for Tissue Engineering Applications.

Tissue or organ damage due to severe injuries or chronic diseases can adversely affect the quality of life. Current treatments rely on organ or tissue transplantation which has limitations including unavailability of donors, ethical issues, or immune rejection after transplantations. These limitations can be addressed by tissue regeneration which involves the development of bioactive scaffolds closely mimicking the extracellular matrix (ECM). One of the major components of ECM is the laminin protein which supports several tissues associated with important organs. In this direction, peptide-based hydrogels can effectively mimic the essential characteristics of laminin. While several reports have discussed the structure of laminin, the potential of laminin-derived peptide hydrogels as effective biomaterial for tissue engineering applications is yet to be discussed. In this context, the current review focuses on the structure of laminin and its role as an essential ECM protein. Further, the potential of short peptide hydrogels in mimicking the crucial properties of laminin is proposed. The review further highlights the significance of bioactive hydrogels inspired by laminin - in addressing numerous tissue engineering applications including angiogenesis, neural, skeletal muscle, liver, and adipose tissue regeneration along with a brief outlook on the future applications of these laminin-based hydrogels.

Expression of the laminin genes family and its relationship to prognosis in pancreatic carcinoma.

BACKGROUND AND STUDY AIMS: Laminin is an extracellular matrix molecule that is the major component of the basement membrane and plays a key role in regulating various processes. However, the association between the laminin gene family and the prognosis of pancreatic carcinoma has not been systematically investigated. PATIENTS AND METHODS: The role of the laminin gene family in pancreatic cancer was evaluated using data from the TCGA database. The effects of different expressions of members of the laminin gene family on pancreatic cancer survival were compared, and their primary cellular roles were examined. The effects of different expressions of positive family genes on proliferation, metastasis, and invasion, as well as EMT and ferroptosis in pancreatic cancer, were also examined. RESULTS: Based on univariate and multifactorial analysis of pancreatic cancer patients, LAMA3 was identified as an independent prognostic factor for overall survival in pancreatic cancer. LAMA3 was found to be enriched in the actin cytoskeleton, P53 signaling pathway, adhesion molecule junctions, pentose phosphate pathway, and regulatory differences in the cell cycle and focal adhesion. Additionally, high expression of LAMA3 was found to promote cancer proliferation, invasion, and metastasis, facilitate the EMT process, and inhibit ferroptosis. CONCLUSIONS: Our results identified LAMA3 was associated with the prognosis of patients with pancreatic cancer and may serve as a prognostic biomarker for pancreatic cancer.

Corrigendum: Comprehensive Analysis of the Expression and Prognosis for Laminin Genes in Ovarian Cancer.

[This corrects the article DOI: 10.3389/pore.2021.1609855.].

Laminin-α4 Negatively Regulates Adipocyte Beiging Through the Suppression of AMPKα in Male Mice.

Laminin-α4 (LAMA4) is an extracellular matrix protein implicated in the regulation of adipocyte differentiation and function. Prior research describes a role for LAMA4 in modulating adipocyte thermogenesis and uncoupling protein-1 (UCP1) expression in white adipose; however, the mechanisms involved are poorly understood. Here, we describe that Lama4 knockout mice (Lama4-/-) exhibit heightened mitochondrial biogenesis and peroxisome proliferator-activated receptor γ coactivator-1 (PGC-1) expression in subcutaneous white adipose tissue (sWAT). Furthermore, the acute silencing of LAMA4 with small interfering RNA in primary murine adipocytes was sufficient to upregulate the expression of thermogenic markers UCP1 and PR domain containing 16 (PRDM16). Silencing also resulted in an upregulation of PGC1-α and adenosine 5'-monophosphate-activated protein kinase (AMPK)-α expression. Subsequently, we show that integrin-linked kinase (ILK) is downregulated in the sWAT of Lama4-/- mice, and its silencing in adipocytes similarly resulted in elevated expression of UCP1 and AMPKα. Last, we demonstrate that treatment of human induced pluripotent stem cell-derived thermogenic adipocytes with LAMA4 (LN411) inhibited the expression of thermogenic markers and AMPKα. Overall, our results indicate that LAMA4 negatively regulates a thermogenic phenotype and pathways involving mitochondrial biogenesis in adipocytes through the suppression of AMPKα.

Recessive LAMA5 Variants Associated With Partial Epilepsy and Spasms in Infancy.

Objective: The LAMA5 gene encodes the laminin subunit α5, the most abundant laminin α subunit in the human brain. It forms heterotrimers with the subunit ß1/ß2 and γ1/γ3 and regulates neurodevelopmental processes. Genes encoding subunits of the laminin heterotrimers containing subunit α5 have been reported to be associated with human diseases. Among LAMAs encoding the laminin α subunit, LAMA1-4 have also been reported to be associated with human disease. In this study, we investigated the association between LAMA5 and epilepsy. Methods: Trios-based whole-exome sequencing was performed in a cohort of 118 infants suffering from focal seizures with or without spasms. Protein modeling was used to assess the damaging effects of variations. The LAMAs expression was analyzed with data from the GTEX and VarCards databases. Results: Six pairs of compound heterozygous missense variants in LAMA5 were identified in six unrelated patients. All affected individuals suffered from focal seizures with mild developmental delay, and three patients presented also spasms. These variants had no or low allele frequencies in controls and presented statistically higher frequency in the case cohort than in controls. The recessive burden analysis showed that recessive LAMA5 variants identified in this cohort were significantly more than the expected number in the East Asian population. Protein modeling showed that at least one variant in each pair of biallelic variants affected hydrogen bonds with surrounding amino acids. Among the biallelic variants in cases with only focal seizures, two variants of each pair were located in different structural domains or domains/links, whereas in the cases with spasms, the biallelic variants were constituted by two variants in the identical functional domains or both with hydrogen bond changes. Conclusion: Recessive LAMA5 variants were potentially associated with infant epilepsy. The establishment of the association between LAMA5 and epilepsy will facilitate the genetic diagnosis and management in patients with infant epilepsy.

Comprehensive Analysis of the Expression and Prognosis for Laminin Genes in Ovarian Cancer.

Survival is low in ovarian cancer (OC). Most OC patients demonstrate advanced metastases, and recurrence is common. Dysregulation of laminin interactions is associated with cancer development. However, it is unknown whether laminin subunits can be considered as biomarkers for OC diagnosis, prognosis, and treatment. We used cBioPortal, GEO, ONCOMINE, GEPIA, Human Protein Atlas, Kaplan-Meier Plotter, TIMER, and Metascape to determine the associations among laminin expression, prognosis, and immune cell infiltration in OC. LAMA5, LAMB3, and LAMC2 mRNAs and LAMA3, LAMB1/B2/B3, and LAMC1/C2 proteins were overexpressed in OC tissues compared with normal ovaries. LAMA4, LAMB1, and LAMC1 mRNA upregulation was positively correlated with worse overall survival (OS) and progression-free survival (PFS) in OC. Elevated LAMA2 and LAMC2 mRNA expression levels were related to better PFS or OS, respectively. The results speculated that LAMA5 could potentially be a good prognostic factor in OC. Its expression proves valuable for predicting OS in patients diagnosed with stage Ⅳ and grade 3 OC and PFS in patients diagnosed with all OC stages or grades. LAMB3 and LAMC2 expression was correlated with platinum resistance development. ROC analysis of laminins in OC sets revealed that LAMA2/A4/A5, LAMB1/B2/B3, and LAMC2 could be used to differentiate between malignant tumors and non-neoplastic tissues. LAMA1/A5 and LAMC1 were significantly and negatively correlated with various tumor immune infiltrates (TILs), especially with dendritic cells, CD8+ T cells or neutrophil. LAMA4 and LAMB1 might be associated with tumor purity in OC. Overall, LAMA5 and LAMC1 could help predict OC survival and diagnosis and might be deemed important OC oncogenes.

Laminin-α4 Is Upregulated in Both Human and Murine Models of Obesity.

Obesity affects nearly one billion globally and can lead to life-threatening sequelae. Consequently, there is an urgent need for novel therapeutics. We have previously shown that laminin, alpha 4 (Lama4) knockout in mice leads to resistance to adipose tissue accumulation; however, the relationship between LAMA4 and obesity in humans has not been established. In this study we measured laminin-α chain and collagen mRNA expression in the subcutaneous white adipose tissue (sWAT) of mice placed on chow (RCD) or 45% high fat diet (HFD) for 8 weeks, and also in HFD mice then placed on a "weight loss" regimen (8 weeks HFD followed by 6 weeks RCD). To assess extracellular matrix (ECM) components in humans with obesity, laminin subunit alpha mRNA and protein expression was measured in sWAT biopsies of female control subjects (BMI<30) or subjects with obesity undergoing bariatric surgery at the University of Chicago Medical Center (BMI>35) both before and three months after surgery. Lama4 was significantly higher in sWAT of HFD compared to RCD mice at both the RNA and protein level (p<0.001, p<0.05 respectively). sWAT from human subjects with obesity also showed significantly higher LAMA4 mRNA (p<0.01) and LAMA4 protein expression (p<0.05) than controls. Interestingly, even though LAMA4 expression was increased in both humans and murine models of obesity, no significant difference in Lama4 or LAMA4 expression was detected following short-term weight loss in either mouse or human samples, respectively. From these results we propose a significant association between obesity and elevated LAMA4 expression in humans, as well as in mouse models of obesity. Further studies should clarify the mechanisms underlying this association to target LAMA4 effectively as a potential therapy for obesity.