scholarly journals Characterization and Expression of the Laminin γ3 Chain: A Novel, Non-Basement Membrane–associated, Laminin Chain

1999 ◽  
Vol 145 (3) ◽  
pp. 605-618 ◽  
Author(s):  
Manuel Koch ◽  
Pamela F. Olson ◽  
Anne Albus ◽  
William Jin ◽  
Dale D. Hunter ◽  
...  
Keyword(s):  
Basement Membrane ◽  
Basement Membranes ◽  
Chromosome 9 ◽  
Seminiferous Tubules ◽  
Apical Surface ◽  
Gene Encoding ◽  
Ductus Deferens ◽  
Functional Roles ◽  
Cloned Gene ◽  
Ciliated Epithelial Cells

Laminins are heterotrimeric molecules composed of an α, a β, and a γ chain; they have broad functional roles in development and in stabilizing epithelial structures. Here, we identified a novel laminin, composed of known α and β chains but containing a novel γ chain, γ3. We have cloned gene encoding this chain, LAMC3, which maps to chromosome 9 at q31-34. Protein and cDNA analyses demonstrate that γ3 contains all the expected domains of a γ chain, including two consensus glycosylation sites and a putative nidogen-binding site. This suggests that γ3-containing laminins are likely to exist in a stable matrix. Studies of the tissue distribution of γ3 chain show that it is broadly expressed in: skin, heart, lung, and the reproductive tracts. In skin, γ3 protein is seen within the basement membrane of the dermal-epidermal junction at points of nerve penetration. The γ3 chain is also a prominent element of the apical surface of ciliated epithelial cells of: lung, oviduct, epididymis, ductus deferens, and seminiferous tubules. The distribution of γ3-containing laminins on the apical surfaces of a variety of epithelial tissues is novel and suggests that they are not found within ultrastructurally defined basement membranes. It seems likely that these apical laminins are important in the morphogenesis and structural stability of the ciliated processes of these cells.

scholarly journals Immunohistochemical Localization of Taurine in the Male Reproductive Organs of the Rat

2000 ◽  
Vol 48 (3) ◽  
pp. 313-320 ◽  
Author(s):  
Maria V.T. Lobo ◽  
F. Javier M. Alonso ◽  
Rafael Martín del Río
Keyword(s):  
Epithelial Cells ◽  
Vascular Endothelial Cells ◽  
Cell Types ◽  
Reproductive Organs ◽  
Immunohistochemical Localization ◽  
Rete Testis ◽  
Male Rat ◽  
Seminiferous Tubules ◽  
Ductus Deferens ◽  
Functional Roles

The amino acid taurine has been implicated in several aspects of reproductive system physiology. However, its localization in these organs has not been previously analyzed. The aim of this study was to characterize its distribution in male rat reproductive organs by immunohistochemical methods. Taurine was localized in the smooth muscle cells of the tissues studied and in the skeletal fibers of the cremaster muscle. In the testis, taurine was found in Leydig cells, vascular endothelial cells, and other interstitial cells. No immunoreactivity was observed in the cells of the seminiferous tubules, either in germ cells at all spermatogenic stages or in Sertoli cells. However, peritubular myoid cells were immunostained. Most epithelial cells of the efferent ducts were immunolabeled, whereas the epithelial cells of the rete testis (extratesticular segments), epididymis (caput, corpus, and cauda regions), and ductus deferens were unstained. However, most epithelial cells from the intratesticular segments of the rete were immunopositive. Some cells identified as intraepithelial macrophages and lymphocytes, apical cells, and narrow cells were intensely immunolabeled. Regional differences in the distribution of these cell types along the ducts studied were also noted. The possible functional roles for taurine in these cells are discussed.

Physical Properties of Isolated Perfused Renal Tubular Basement Membranes

1971 ◽  
Vol 29 ◽  
pp. 390-391
Author(s):  
Jared Grantham ◽  
Larry Welling
Keyword(s):  
Basement Membrane ◽  
Basement Membranes ◽  
Transport Mechanisms ◽  
Permeability Characteristics ◽  
Peritubular Capillaries ◽  
Strategic Location ◽  
Tubular Lumen ◽  
Glomerular Filtrate ◽  
Urine Formation ◽  
Renal Tubular

In the course of urine formation in mammalian kidneys over 90% of the glomerular filtrate moves from the tubular lumen into the peritubular capillaries by both active and passive transport mechanisms. In all of the morphologically distinct segments of the renal tubule, e.g. proximal tubule, loop of Henle and distal nephron, the tubular absorbate passes through a basement membrane which rests against the basilar surface of the epithelial cells. The basement membrane is in a strategic location to affect the geometry of the tubules and to influence the movement of tubular absorbate into the renal interstitium. In the present studies we have determined directly some of the mechanical and permeability characteristics of tubular basement membranes.

scholarly journals SARS-CoV-2 infection and recurrence of anti-glomerular basement disease: a case report

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Alexander Winkler ◽  
Emanuel Zitt ◽  
Hannelore Sprenger-Mähr ◽  
Afschin Soleiman ◽  
Manfred Cejna ◽  
...  
Keyword(s):  
Basement Membrane ◽  
Glomerular Basement Membrane ◽  
Plasma Cells ◽  
Rapidly Progressive Glomerulonephritis ◽  
Kidney Injury ◽  
Pulmonary Involvement ◽  
Pulmonary Haemorrhage ◽  
Basement Membranes ◽  
High Avidity ◽  
History Of

Abstract Background Anti-glomerular basement membrane disease (GBM) disease is a rare autoimmune disease causing rapidly progressive glomerulonephritis and pulmonary haemorrhage. Recently, an association between COVID-19 and anti-glomerular basement membrane (anti-GBM) disease has been proposed. We report on a patient with recurrence of anti-GBM disease after SARS-CoV-2 infection. Case presentation The 31-year-old woman had a past medical history of anti-GBM disease, first diagnosed 11 years ago, and a first relapse 5 years ago. She was admitted with severe dyspnoea, haemoptysis, pulmonary infiltrates and acute on chronic kidney injury. A SARS-CoV-2 PCR was positive with a high cycle threshold. Anti-GBM autoantibodies were undetectable. A kidney biopsy revealed necrotising crescentic glomerulonephritis with linear deposits of IgG, IgM and C3 along the glomerular basement membrane, confirming a recurrence of anti-GBM disease. She was treated with steroids, plasma exchange and two doses of rituximab. Pulmonary disease resolved, but the patient remained dialysis-dependent. We propose that pulmonary involvement of COVID-19 caused exposure of alveolar basement membranes leading to the production of high avidity autoantibodies by long-lived plasma cells, resulting in severe pulmonary renal syndrome. Conclusion Our case supports the assumption of a possible association between COVID-19 and anti-GBM disease.

scholarly journals Die Kaliumhydrogenphosphat-induzierte Nephropathie des Hundes. I. Pathogenese der Tubulusatrophiee [Potassium Hydrogen Phosphate Induced Nephropathy in the Dog. I. Pathogenesis of Tubular Atrophy—author's trans.]

1980 ◽  
Vol 17 (6) ◽  
pp. 699-719 ◽  
Author(s):  
P. Schneider ◽  
G. Pappritz ◽  
R. Müller-Peddinghaus ◽  
M. Bauer ◽  
H. Lehmann ◽  
...  
Keyword(s):  
Acid Phosphatase ◽  
Epithelial Cells ◽  
Basement Membrane ◽  
Basement Membranes ◽  
Tubular Epithelial Cells ◽  
Beagle Dogs ◽  
Lysosomal Degradation ◽  
Tubular Basement Membrane ◽  
Tubular Atrophy ◽  
Study Results

A nephropathy with severe tubular atrophy was observed in Beagle dogs after oral administration of K2HPO4 for 14 or 38 weeks. We describe the complete lysosomal degradation of atrophying tubular epithelial cells. During two experiments of 14 and 38 weeks duration, respectively, a total of 15 Beagle dogs received 0.8 g K2HPO4/kg body weight daily with their food. All dogs were examined clinically at regular intervals. Renal biopsies were taken in the fourth week from beagles of the 14-week study. Results were compared with those of control dogs. At the end of the experiments the animals were killed and necropsies done. Different stains and histochemical reactions were applied to paraffin sections of the kidneys. Acid phosphatase and β-glucuronidase were found on cryostat sections. Kidneys fixed by perfusion of five Beagles from the 38-week study and three Beagles of the 14-week study, and from five control dogs, were examined electron microscopically. Ultrahistochemically, acid phosphatase was demonstrated. Clinically, the dogs in both experiments vomited, were cachectic, and had elevated creatinine and blood urea nitrogen. Morphologically, qualitatively identical changes were seen, but the renal damage was most marked at 38 weeks. There were disseminated tubular atrophy (usually of the proximal tubules), focal scar tissue and nephrocalcinosis. The following pathogenesis was established for the lesions of the proximal tubule: Tubular atrophy begins with loss of differentiation of epithelial cells. Enzyme histochemistry, ultrahistochemistry and electron microscopy show an increase in autophagic vacuoles and autophagolysosomes. The lysosomal bodies showing fusion enclose large parts of the cytoplasm as the process continues. Complete lysosomal degradation of epithelial cells and extrusion of large lysosomes into the tubular lumen follow. After complete enzymatic digestion of the intratubular detritus, the residue is empty, convoluted and collapsed tubular basement membrane. Atrophic tubular epithelial cells have many organelle-free zones at their base, which contain fine filamentous material resembling that of the basement membrane. The degradation processes described here may explain why clinically the urinary sediment contains few cylinders and epithelial cells and why proteinuria decreases significantly toward the end of the experiment. So far, it is not clear whether the tubular basement membrane is synthesized by the tubular cells, by fibroblasts or by both cell types. The presence of basement membrane-like material in tubular epithelial cells and in parietal epithelial cells of the glomerulus favors the view that epithelial cells produce the basement membranes and that increased production of basement membrane-like material is a sign of loss of differentiation.

scholarly journals Characterization of the Gene Encoding the Major Secreted Lysophospholipase A of Legionella pneumophila and Its Role in Detoxification of Lysophosphatidylcholine

2002 ◽  
Vol 70 (11) ◽  
pp. 6094-6106 ◽  
Author(s):  
Antje Flieger ◽  
Birgid Neumeister ◽  
Nicholas P. Cianciotto
Keyword(s):  
Fatty Acids ◽  
Legionella Pneumophila ◽  
Lipolytic Activity ◽  
Cholesterol Acyltransferase ◽  
Phospholipase A ◽  
Wild Type ◽  
Gene Encoding ◽  
Acyltransferase Activity ◽  
Lipolytic Enzymes ◽  
Cloned Gene

ABSTRACT We previously showed that Legionella pneumophila secretes, via its type II secretion system, phospholipase A activities that are distinguished by their specificity for certain phospholipids. In this study, we identified and characterized plaA, a gene encoding a phospholipase A that cleaves fatty acids from lysophospholipids. The plaA gene encoded a 309-amino-acid protein (PlaA) which had homology to a group of lipolytic enzymes containing the catalytic signature GDSL. In Escherichia coli, the cloned gene conferred trypsin-resistant hydrolysis of lysophosphatidylcholine and lysophosphatidylglycerol. An L. pneumophila plaA mutant was generated by allelic exchange. Although the mutant grew normally in standard buffered yeast extract broth, its culture supernatants lost greater than 80% of their ability to release fatty acids from lysophosphatidylcholine and lysophosphatidylglycerol, implying that PlaA is the major secreted lysophospholipase A of L. pneumophila. The mutant's reduced lipolytic activity was confirmed by growth on egg yolk agar and thin layer chromatography and was complemented by reintroduction of an intact copy of plaA. Overexpression of plaA completely protected L. pneumophila from the toxic effects of lysophosphatidylcholine, suggesting a role for PlaA in bacterial detoxification of lysophospholipids. The plaA mutant grew like the wild type in U937 cell macrophages and Hartmannella vermiformis amoebae, indicating that PlaA is not essential for intracellular infection of L. pneumophila. In the course of characterizing plaA, we discovered that wild-type legionellae secrete a phospholipid cholesterol acyltransferase activity, highlighting the spectrum of lipolytic enzymes produced by L. pneumophila.

Endothelial k-RasV12 Expression Induces Capillary Deficiency Attributable to Marked Tube Network Expansion Coupled to Reduced Pericytes and Basement Membranes

2021 ◽  
Author(s):  
Zheying Sun ◽  
Scott S. Kemp ◽  
Prisca K. Lin ◽  
Kalia N. Aguera ◽  
George E. Davis
Keyword(s):  
Protein Kinase ◽  
Basement Membrane ◽  
Arteriovenous Malformations ◽  
Network Formation ◽  
Tube Formation ◽  
Small Gtpase ◽  
Basement Membranes ◽  
Formation Mechanisms ◽  
Lumen Formation ◽  
The Impact

Objective: We sought to determine how endothelial cell (EC) expression of the activating k-Ras mutation, k-RasV12, affects their ability to form lumens and tubes and interact with pericytes during capillary assembly Approach and Results: Using defined bioassays where human ECs undergo observable tubulogenesis, sprouting behavior, pericyte recruitment to EC-lined tubes, and pericyte-induced EC basement membrane deposition, we assessed the impact of EC k-RasV12 expression on these critical processes that are necessary for proper capillary network formation. This mutation, which is frequently seen in human ECs within brain arteriovenous malformations, was found to markedly accentuate EC lumen formation mechanisms, with strongly accelerated intracellular vacuole formation, vacuole fusion, and lumen expansion and with reduced sprouting behavior, leading to excessively widened tube networks compared with control ECs. These abnormal tubes demonstrate strong reductions in pericyte recruitment and pericyte-induced EC basement membranes compared with controls, with deficiencies in fibronectin, collagen type IV, and perlecan deposition. Analyses of signaling during tube formation from these k-RasV12 ECs reveals strong enhancement of Src, Pak2 (P21 [RAC1 (Rac family small GTPase 1)] activated kinase 2), b-Raf (v-raf murine sarcoma viral oncogene homolog B1), Erk (extracellular signal–related kinase), and Akt activation and increased expression of PKCε (protein kinase C epsilon), MT1-MMP (membrane-type 1 matrix metalloproteinase), acetylated tubulin and CDCP1 (CUB domain-containing protein 1; most are known EC lumen regulators). Pharmacological blockade of MT1-MMP, Src, Pak, Raf, Mek (mitogen-activated protein kinase) kinases, Cdc42 (cell division cycle 42)/Rac1, and Notch markedly interferes with lumen and tube formation from these ECs. Conclusions: Overall, this novel work demonstrates that EC expression of k-RasV12 disrupts capillary assembly due to markedly excessive lumen formation coupled with strongly reduced pericyte recruitment and basement membrane deposition, which are critical pathogenic features predisposing the vasculature to develop arteriovenous malformations.

An essential yeast gene encoding a TTAGGG repeat-binding protein

1993 ◽  
Vol 13 (2) ◽  
pp. 1306-1314
Author(s):  
C Brigati ◽  
S Kurtz ◽  
D Balderes ◽  
G Vidali ◽  
D Shore
Keyword(s):  
Dna Binding ◽  
Binding Protein ◽  
Binding Activity ◽  
Insertion Mutation ◽  
Yeast Gene ◽  
Gene Encoding ◽  
Cloned Gene ◽  
Diploid Cells ◽  
Ttaggg Repeat

A yeast gene encoding a DNA-binding protein that recognizes the telomeric repeat sequence TTAGGG found in multicellular eukaryotes was identified by screening a lambda gt11 expression library with a radiolabeled TTAGGG multimer. This gene, which we refer to as TBF1 (TTAGGG repeat-binding factor 1), encodes a polypeptide with a predicted molecular mass of 63 kDa. The TBF1 protein, produced in vitro by transcription and translation of the cloned gene, binds to (TTAGGG)n probes and to a yeast telomeric junction sequence that contains two copies of the sequence TTAGGG separated by 5 bp. TBF1 appears to be identical to a previously described yeast TTAGGG-repeat binding activity called TBF alpha. TBF1 produced in vitro yields protein-DNA complexes with (TTAGGG)n probes that have mobilities on native polyacrylamide gels identical to those produced by partially purified TBF alpha from yeast cells. Furthermore, when extracts are prepared from a strain containing a TBF1 gene with an antigen tag, we find that the antigen copurifies with the predominant (TTAGGG)n-binding activity in the extracts. The DNA sequence of TBF1 was determined. The predicted protein sequence suggests that TBF1 may contain a nucleotide-binding domain, but no significant similarities to any other known proteins were identified, nor was an obvious DNA-binding motif apparent. Diploid cells heterozygous for a tbf1::URA3 insertion mutation are viable but upon sporulation give rise to tetrads with only two viable spores, both of which are Ura-, indicating that the TBF1 gene is essential for growth. Possible functions of TBF1 (TFB alpha) are discussed in light of these new results.

scholarly journals The Emerging Role of DNA Damage in the Pathogenesis of the C9orf72 Repeat Expansion in Amyotrophic Lateral Sclerosis

2018 ◽  
Vol 19 (10) ◽  
pp. 3137 ◽  
Author(s):  
Anna Konopka ◽  
Julie Atkin
Keyword(s):  
Dna Damage ◽  
Amyotrophic Lateral Sclerosis ◽  
Motor Neurons ◽  
Repeat Expansion ◽  
Chromosome 9 ◽  
Gene Encoding ◽  
C9orf72 Repeat Expansion ◽  
Reading Frame ◽  
Early Onset Dementia ◽  
Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is a fatal, rapidly progressing neurodegenerative disease affecting motor neurons, and frontotemporal dementia (FTD) is a behavioural disorder resulting in early-onset dementia. Hexanucleotide (G4C2) repeat expansions in the gene encoding chromosome 9 open reading frame 72 (C9orf72) are the major cause of familial forms of both ALS (~40%) and FTD (~20%) worldwide. The C9orf72 repeat expansion is known to form abnormal nuclei acid structures, such as hairpins, G-quadruplexes, and R-loops, which are increasingly associated with human diseases involving microsatellite repeats. These configurations form during normal cellular processes, but if they persist they also damage DNA, and hence are a serious threat to genome integrity. It is unclear how the repeat expansion in C9orf72 causes ALS, but recent evidence implicates DNA damage in neurodegeneration. This may arise from abnormal nucleic acid structures, the greatly expanded C9orf72 RNA, or by repeat-associated non-ATG (RAN) translation, which generates toxic dipeptide repeat proteins. In this review, we detail recent advances implicating DNA damage in C9orf72-ALS. Furthermore, we also discuss increasing evidence that targeting these aberrant C9orf72 confirmations may have therapeutic value for ALS, thus revealing new avenues for drug discovery for this disorder.

scholarly journals Stratification of Antigen-presenting Cells within the Normal Cornea

2009 ◽  
Vol 1 ◽  
pp. OED.S2813 ◽  
Author(s):  
Jared E. Knickelbein ◽  
Simon C. Watkins ◽  
Paul G. Mcmenamin ◽  
Robert L. Hendricks
Keyword(s):  
Bone Marrow ◽  
Basement Membrane ◽  
Mhc Class Ii ◽  
Fluorescent Protein ◽  
Antigen Presenting Cells ◽  
Class Ii ◽  
Apical Surface ◽  
Bone Marrow Derived Cells ◽  
Green Fluorescent ◽  
Antigen Presenting

The composition and location of professional antigen presenting cells (APC) varies in different mucosal surfaces. The cornea, long considered an immune-privileged tissue devoid of APCs, is now known to host a heterogeneous network of bone marrow-derived cells. Here, we utilized transgenic mice that express enhanced green fluorescent protein (EGFP) from the CD 11c promoter (pCD11c) in conjunction with immunohistochemical staining to demonstrate an interesting stratification of APCs within non-inflamed murine corneas. pCD11c+ dendritic cells (DCs) reside in the basal epithelium, seemingly embedded in the basement membrane. Most DCs express MHC class II on at least some dendrites, which extend up to 50 μm in length and traverse up 20 μm tangentially towards the apical surface of the epithelium. The DC density diminishes from peripheral to central cornea. Beneath the DCs and adjacent to the stromal side of the basement membrane reside pCD11c–CD11b+ putative macrophages that express low levels of MHC class II. Finally, MHC class II–pCD11c–CD11b+ cells form a network throughout the remainder of the stroma. This highly reproducible stratification of bone marrow-derived cells is suggestive of a progression from an APC function at the exposed corneal surface to an innate immune barrier function deeper in the stroma.

Antiglomerular Basement Membrane Disease

2018 ◽  
Vol 39 (04) ◽  
pp. 494-503 ◽  
Author(s):  
Charles Pusey ◽  
Stephen McAdoo
Keyword(s):  
Basement Membrane ◽  
Rapidly Progressive Glomerulonephritis ◽  
Basement Membranes ◽  
Alveolar Hemorrhage ◽  
Type Iv ◽  
Maintenance Immunosuppression ◽  
Life Threatening ◽  
Renal Prognosis ◽  
Function Testing

AbstractAntiglomerular basement membrane (anti-GBM) disease is a rare but life-threatening autoimmune vasculitis that is characterized by the development of pathogenic autoantibodies to type IV collagen antigens expressed in the glomerular and alveolar basement membranes. Once deposited in tissue, these autoantibodies incite a local capillaritis which manifests as rapidly progressive glomerulonephritis (GN) in 80 to 90% of patients, and with concurrent alveolar hemorrhage in ∼50%. A small proportion of cases may present with pulmonary disease in isolation. Serological testing for anti-GBM antibodies may facilitate rapid diagnosis, though renal biopsy is often required to confirm the presence of necrotizing or crescentic GN and linear deposition of autoantibody on the glomerular basement membrane. Alveolar hemorrhage may be evident clinically, or detected on imaging, pulmonary function testing, or bronchoscopy. Prompt treatment with plasmapheresis, cyclophosphamide, and steroids is usually indicated to remove pathogenic autoantibodies, to prevent their ongoing production, and to ameliorate end-organ inflammation. Alveolar hemorrhage is usually responsive to this treatment, and long-term respiratory sequelae are uncommon. Renal prognosis is more variable, though with aggressive treatment, independent renal function is maintained at 1 year in more than 80% of patients not requiring renal replacement therapy at presentation. Relapse in uncommon in anti-GBM disease, unless there is a concomitant antineutrophil cytoplasm antibody (present in 30–40%), in which case maintenance immunosuppression is recommended.

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