Functional diversity of laminins Domogatskaya, Anna; Rodin, Sergey; Tryggvason, Karl
Annual review of cell and developmental biology,
01/2012, Letnik:
28
Journal Article
Recenzirano
Laminins are a large family of conserved, multidomain trimeric basement membrane proteins that contribute to the structure of extracellular matrix and influence the behavior of associated cells, such ...as adhesion, differentiation, migration, phenotype stability, and resistance to anoikis. In lower organisms such as Hydra there is only one isoform of laminin, but higher organisms have at least 16 trimeric isoforms with varying degrees of cell/tissue specificity. In vitro protein and cell culture studies, gene manipulation in animals, and laminin gene mutations in human diseases have provided insight into the specific functions of some laminins, but the biological roles of many isoforms are still largely unexplored, mainly owing to difficulties in isolating them in pure form from tissues or cells. In this review, we elucidate the evolution of laminins, describe their molecular complexity, and explore the current knowledge of their diversity and functional aspects, including laminin-mediated signaling via membrane receptors, in vitro cell biology, and involvement in various tissues gained from animal model and human disease studies. The potential use of laminins in cell biology research and biotechnology is discussed.
This review summarizes recent advances in our knowledge of the glomerular filter and the causes of hereditary proteinuria syndromes.
This review summarizes recent advances in our knowledge of the ...glomerular filter and the causes of hereditary proteinuria syndromes.
The inherited forms of proteinuria comprise a heterogeneous group of rare renal diseases in which glomerular dysfunction and proteinuria are prominent. Despite the rarity of hereditary proteinuria syndromes, genetic, biochemical, and structural studies of these diseases have made important contributions to our knowledge of how the normal glomerular filter works and the mechanisms of proteinuria.
The courses of these diseases can vary. Some patients present with severe proteinuria and congenital nephrotic syndrome, whereas others have only moderate proteinuria and focal segmental glomerulosclerosis. Regardless of its cause, the disease often progresses to end-stage renal disease. Classification of these syndromes has been . . .
A robust method for culturing human pluripotent stem (hPS) cells under chemically defined and xeno-free conditions is an important tool for stem cell research and for the development of regenerative ...medicine. Here, we describe a protocol for monolayer culturing of Oct-4-positive hPS cells on a specific laminin-521 (LN-521) isoform, under xeno-free and chemically defined conditions. The cells are dispersed into single-cell suspension and then plated on LN-521 isoform at densities higher than 5,000 cells per cm², where they attach, migrate and survive by forming small monolayer cell groups. The cells avidly divide and expand horizontally until the entire dish is covered by a confluent monolayer. LN-521, in combination with E-cadherin, allows cloning of individual hPS cells in separate wells of 96-well plates without the presence of rho-associated protein kinase (ROCK) inhibitors or any other inhibitors of anoikis. Characterization of cells maintained for several months in culture reveals pluripotency with a minimal degree of genetic abnormalities.
The glomerular filtration barrier is composed of glomerular endothelial cells, the glomerulus basement membrane and the podocyte cell layer. The filtration barrier is a target of injury in several ...systemic and renal diseases, and this often leads to progressive renal disease and kidney failure. Therefore, it is essential to understand the molecular biology of the glomerulus. During the last two decades, a lot of new information about molecular components of the glomerulus filtration barrier has been generated. Many of the key discoveries have been obtained through studies on the genetic background of inherited glomerular diseases. These studies have emphasized the role of podocytes in the filtration barrier function. During the last decade, the use of knockout mouse technology has become more available and given important new insights into the functional significance of glomerular components. Large-scale approaches, such as microarray profiling, have also given data about molecules involved in the biology and pathology of the glomerulus. In the coming decade, the use of global expression profiling platforms, transgenic mouse lines, and other
in vivo gene delivery methods will rapidly expand our understanding of biology and pathology of the glomerular filtration barrier, and hopefully expose novel target molecules for therapy in progressive renal diseases.
We describe a system for culturing human embryonic stem (hES) cells and induced pluripotent stem (iPS) cells on a recombinant form of human laminin-511, a component of the natural hES cell niche. The ...system is devoid of animal products and feeder cells and contains only one undefined component, human albumin. The hES cells self-renewed with normal karyotype for at least 4 months (20 passages), after which the cells could produce teratomas containing cell lineages of all three germ layers. When plated on laminin-511 in small clumps, hES cells spread out in a monolayer, maintaining cellular homogeneity with approximately 97% OCT4-positive cells. Adhesion of hES cells was dependent on α6β1 integrin. The use of homogeneous monolayer hES or iPS cell cultures provides more controllable conditions for the design of differentiation methods. This xeno-free and feeder-free system may be useful for the development of cell lineages for therapeutic purposes.
Lack of robust methods for establishment and expansion of pluripotent human embryonic stem (hES) cells still hampers development of cell therapy. Laminins (LN) are a family of highly cell-type ...specific basement membrane proteins important for cell adhesion, differentiation, migration and phenotype stability. Here we produce and isolate a human recombinant LN-521 isoform and develop a cell culture matrix containing LN-521 and E-cadherin, which both localize to stem cell niches in vivo. This matrix allows clonal derivation, clonal survival and long-term self-renewal of hES cells under completely chemically defined and xeno-free conditions without ROCK inhibitors. Neither LN-521 nor E-cadherin alone enable clonal survival of hES cells. The LN-521/E-cadherin matrix allows hES cell line derivation from blastocyst inner cell mass and single blastomere cells without a need to destroy the embryo. This method can facilitate the generation of hES cell lines for development of different cell types for regenerative medicine purposes.
Translated small open reading frames (smORFs) can have important regulatory roles and encode microproteins, yet their genome-wide identification has been challenging. We determined the ribosome ...locations across six primary human cell types and five tissues and detected 7,767 smORFs with translational profiles matching those of known proteins. The human genome was found to contain highly cell-type- and tissue-specific smORFs and a subset that encodes highly conserved amino acid sequences. Changes in the translational efficiency of upstream-encoded smORFs (uORFs) and the corresponding main ORFs predominantly occur in the same direction. Integration with 456 mass-spectrometry datasets confirms the presence of 603 small peptides at the protein level in humans and provides insights into the subcellular localization of these small proteins. This study provides a comprehensive atlas of high-confidence translated smORFs derived from primary human cells and tissues in order to provide a more complete understanding of the translated human genome.
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•Ribosome profiling (Ribo-seq) of 11 human primary cells and tissues reveals 7,767 high-confidence smORFs•smORFs exhibit cell-type/tissue specificity, and 603 SEPs were detected in MS data•Dynamic changes in the TE of uORF and main ORF pairs are mostly homodirectional•An interactive browser for this study can be found at https://smorfs.ddnetbio.com
Chothani et al. evaluate ribosome-mRNA interactions across six cell types and five tissues and reveal 7,767 small regions outside of the protein-coding genome that are actively translated in humans. These include specifically expressed and highly conserved small open reading frames. The integration of proteomics reveals more than 600 small proteins.
Phagocytic and pathogen sensing receptors are responsible for particle uptake and inflammation. It is unclear how these receptors' systems influence each other's function to shape an innate response. ...The class-A scavenger receptors SR-A (scavenger receptor A) and MARCO (macrophage receptor with collagenous structure) are 2 well-characterized phagocytic receptors that are unable to initiate inflammatory responses by themselves, yet are implicated in the pathogenesis of various inflammatory disorders. However, the mechanism for such an apparent discrepancy is still unclear. We utilized SR-A−/−, MARCO−/−, and SR-A−/−-MARCO−/− mice, along with microbe-derived, environmental, and synthetic polyanions to assess the inflammatory responses following combinatorial ligation of SR-A/MARCO and selected Toll-like receptors (TLRs) and nucleotide-binding oligomerization domain (NOD)–like receptors (NLRs) by their shared ligands. In addition to ligating SR-A and MARCO, these agonists also selectively activated the cell-surface sensor TLR4, endosomal TLR3, and the cytosolic NOD2 and NALP3 (NACHT domain–, leucine-rich repeat–, and pyrin domain–containing protein 3). We show that, following recognition of common ligands, SR-A and MARCO attenuate TLR4-mediated responses while enhancing responses by the intracellular TLR3, NOD2, and NALP3. We conclude that SR-A/MARCO-mediated rapid ligand internalization prevented sensing by surface TLRs while increasing ligand availability in intracellular compartments, thus allowing sensing and robust responses by intracellular sensors.
Laminin
5
2
1 (LM-521) is a major component of the GBM. Mutations in
that prevent LM-521 synthesis and/or secretion cause Pierson syndrome, a rare congenital nephrotic syndrome with diffuse mesangial ...sclerosis and ocular and neurologic defects. Because the GBM is uniquely accessible to plasma, which permeates endothelial cell fenestrae, we hypothesized that intravenous delivery of LM-521 could replace the missing LM-521 in the GBM of
mutant mice and restore glomerular permselectivity.
We injected human LM-521 (hLM-521), a macromolecule of approximately 800 kD, into the retro-orbital sinus of
-/- pups daily. Deposition of hLM-521 into the GBM was investigated by fluorescence microscopy. We assayed the effects of hLM-521 on glomerular permselectivity by urinalysis and the effects on podocytes by desmin immunostaining and ultrastructural analysis of podocyte architecture.
Injected hLM-521 rapidly and stably accumulated in the GBM of all glomeruli. Super-resolution imaging showed that hLM-521 accumulated in the correct orientation in the GBM, primarily on the endothelial aspect. Treatment with hLM-521 greatly reduced the expression of the podocyte injury marker desmin and attenuated the foot process effacement observed in untreated pups. Moreover, treatment with hLM-521 delayed the onset of proteinuria but did not prevent nephrotic syndrome, perhaps due to its absence from the podocyte aspect of the GBM.
These studies show that GBM composition and function can be altered
vascular delivery of even very large proteins, which may advance therapeutic options for patients with abnormal GBM composition, whether genetic or acquired.
Virtually all of the elements of Mycobacterium tuberculosis (Mtb) pathogenesis, including pro-inflammatory cytokine production, granuloma formation, cachexia, and mortality, can be induced by its ...predominant cell wall glycolipid, trehalose 6,6'-dimycolate (TDM/cord factor). TDM mediates these potent inflammatory responses via interactions with macrophages both in vitro and in vivo in a myeloid differentiation factor 88 (MyD88)-dependent manner via phosphorylation of the mitogen activated protein kinases (MAPKs), implying involvement of toll-like receptors (TLRs). However, specific TLRs or binding receptors for TDM have yet to be identified. Herein, we demonstrate that the macrophage receptor with collagenous structure (MARCO), a class A scavenger receptor, is utilized preferentially to "tether" TDM to the macrophage and to activate the TLR2 signaling pathway. TDM-induced signaling, as measured by a nuclear factor-kappa B (NF-kappaB)-luciferase reporter assay, required MARCO in addition to TLR2 and CD14. MARCO was used preferentially over the highly homologous scavenger receptor class A (SRA), which required TLR2 and TLR4, as well as their respective accessory molecules, in order for a slight increase in NF-kappaB signaling to occur. Consistent with these observations, macrophages from MARCO(-/-) or MARCO(-/-)SRA(-/-) mice are defective in activation of extracellular signal-related kinase 1/2 (ERK1/2) and subsequent pro-inflammatory cytokine production in response to TDM. These results show that MARCO-expressing macrophages secrete pro-inflammatory cytokines in response to TDM by cooperation between MARCO and TLR2/CD14, whereas other macrophage subtypes (e.g. bone marrow-derived) may rely somewhat less effectively on SRA, TLR2/CD14, and TLR4/MD2. Macrophages from MARCO(-/-) mice also produce markedly lower levels of pro-inflammatory cytokines in response to infection with virulent Mtb. These observations identify the scavenger receptors as essential binding receptors for TDM, explain the differential response to TDM of various macrophage populations, which differ in their expression of the scavenger receptors, and identify MARCO as a novel component required for TLR signaling.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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