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Autophagy 2015A homozygous mutation in the DST (dystonin) gene causes a newly identified lethal form of hereditary sensory and autonomic neuropathy in humans (HSAN-VI). DST loss of...
A homozygous mutation in the DST (dystonin) gene causes a newly identified lethal form of hereditary sensory and autonomic neuropathy in humans (HSAN-VI). DST loss of function similarly leads to sensory neuron degeneration and severe ataxia in dystonia musculorum (Dst(dt)) mice. DST is involved in maintaining cytoskeletal integrity and intracellular transport. As autophagy is highly reliant upon stable microtubules and motor proteins, we assessed the influence of DST loss of function on autophagy using the Dst(dt-Tg4) mouse model. Electron microscopy (EM) revealed an accumulation of autophagosomes in sensory neurons from these mice. Furthermore, we demonstrated that the autophagic flux was impaired. Levels of LC3-II, a marker of autophagosomes, were elevated. Consequently, Dst(dt-Tg4) sensory neurons displayed impaired protein turnover of autophagosome substrate SQTSM1/p62 and of polyubiquitinated proteins. Interestingly, in a previously described Dst(dt-Tg4) mouse model that is partially rescued by neuronal specific expression of the DST-A2 isoform, autophagosomes, autolysosomes, and damaged organelles were reduced when compared to Dst(dt-Tg4) mutant mice. LC3-II, SQTSM1, polyubiquitinated proteins and autophagic flux were also restored to wild-type levels in the rescued mice. Finally, a significant decrease in DNAIC1 (dynein, axonemal, intermediate chain 1; the mouse ortholog of human DNAI1), a member of the DMC (dynein/dynactin motor complex), was noted in Dst(dt-Tg4) dorsal root ganglia and sensory neurons. Thus, DST-A2 loss of function perturbs late stages of autophagy, and dysfunctional autophagy at least partially underlies Dst(dt) pathogenesis. We therefore conclude that the DST-A2 isoform normally facilitates autophagy within sensory neurons to maintain cellular homeostasis.
Topics: Adaptor Proteins, Signal Transducing; Animals; Autophagy; Carrier Proteins; Cytoskeletal Proteins; Dynactin Complex; Dystonia; Dystonin; Heat-Shock Proteins; Mice, Transgenic; Microtubule-Associated Proteins; Microtubules; Nerve Tissue Proteins; Phagosomes; Sensory Receptor Cells; Sequestosome-1 Protein
PubMed: 26043942
DOI: 10.1080/15548627.2015.1052207 -
Molecular Biology of the Cell Oct 2003Plectin is a major component of the cytoskeleton and links the intermediate filament system to hemidesmosomes by binding to the integrin beta4 subunit. Previously, a...
Plectin is a major component of the cytoskeleton and links the intermediate filament system to hemidesmosomes by binding to the integrin beta4 subunit. Previously, a binding site for beta4 was mapped on the actin-binding domain (ABD) of plectin and binding of beta4 and F-actin to plectin was shown to be mutually exclusive. Here we show that only the ABDs of plectin and dystonin bind to beta4, whereas those of other actin-binding proteins do not. Mutations of the ABD of plectin-1C show that Q131, R138, and N149 are critical for tight binding of the ABD to beta4. These residues form a small cavity, occupied by a well-ordered water molecule in the crystal structure. The beta4 binding pocket partly overlaps with the actin-binding sequence 2 (ABS2), previously shown to be essential for actin binding. Therefore, steric interference may render binding of beta4 and F-actin to plectin mutually exclusive. Finally, we provide evidence indicating that the residues preceding the ABD in plectin-1A and -1C, although unable to mediate binding to beta4 themselves, modulate the binding activity of the ABD for beta4. These studies demonstrate the unique property of the plectin-ABD to bind to both F-actin and beta4, and explain why several other ABD-containing proteins that are expressed in basal keratinocytes are not recruited into hemidesmosomes.
Topics: Actins; Amino Acid Sequence; Animals; COS Cells; Carrier Proteins; Cells, Cultured; Chlorocebus aethiops; Cytoskeletal Proteins; Cytoskeleton; Dystonin; Fluorescent Antibody Technique; Humans; Integrin beta4; Intermediate Filament Proteins; Molecular Sequence Data; Mutation; Nerve Tissue Proteins; Plectin; Protein Binding; Protein Isoforms; Protein Structure, Tertiary; Rats; Reverse Transcriptase Polymerase Chain Reaction; Sequence Alignment; Two-Hybrid System Techniques
PubMed: 14517317
DOI: 10.1091/mbc.e03-05-0268 -
The Journal of Cell Biology Jul 1998Hemidesmosomes (HDs) are stable anchoring structures that mediate the link between the intermediate filament cytoskeleton and the cell substratum. We investigated the...
Hemidesmosome formation is initiated by the beta4 integrin subunit, requires complex formation of beta4 and HD1/plectin, and involves a direct interaction between beta4 and the bullous pemphigoid antigen 180.
Hemidesmosomes (HDs) are stable anchoring structures that mediate the link between the intermediate filament cytoskeleton and the cell substratum. We investigated the contribution of various segments of the beta4 integrin cytoplasmic domain in the formation of HDs in transient transfection studies using immortalized keratinocytes derived from an epidermolysis bullosa patient deficient in beta4 expression. We found that the expression of wild-type beta4 restored the ability of the beta4-deficient cells to form HDs and that distinct domains in the NH2- and COOH-terminal regions of the beta4 cytoplasmic domain are required for the localization of HD1/plectin and the bullous pemphigoid antigens 180 (BP180) and 230 (BP230) in these HDs. The tyrosine activation motif located in the connecting segment (CS) of the beta4 cytoplasmic domain was dispensable for HD formation, although it may be involved in the efficient localization of BP180. Using the yeast two-hybrid system, we could demonstrate a direct interaction between beta4 and BP180 which involves sequences within the COOH-terminal part of the CS and the third fibronectin type III (FNIII) repeat. Immunoprecipitation studies using COS-7 cells transfected with cDNAs for alpha6 and beta4 and a mutant BP180 which lacks the collagenous extracellular domain confirmed the interaction of beta4 with BP180. Nevertheless, beta4 mutants which contained the BP180-binding region, but lacked sequences required for the localization of HD1/plectin, failed to localize BP180 in HDs. Additional yeast two- hybrid assays indicated that the 85 COOH-terminal residues of beta4 can interact with the first NH2-terminal pair of FNIII repeats and the CS, suggesting that the cytoplasmic domain of beta4 is folded back upon itself. Unfolding of the cytoplasmic domain may be part of a mechanism by which the interaction of beta4 with other hemidesmosomal components, e.g., BP180, is regulated.
Topics: Animals; Antigens, CD; Autoantigens; Binding Sites; COS Cells; Carrier Proteins; Cell Line, Transformed; Cells, Cultured; Cytoplasm; Cytoskeletal Proteins; Dystonin; Epidermolysis Bullosa, Junctional; Humans; Integrin alpha6; Integrin beta1; Integrin beta4; Intermediate Filament Proteins; Keratinocytes; Nerve Tissue Proteins; Non-Fibrillar Collagens; Plectin; Precipitin Tests; Tyrosine; Collagen Type XVII
PubMed: 9660880
DOI: 10.1083/jcb.142.1.271 -
The Journal of Investigative Dermatology Dec 2019Deposition of autoantibodies (α-BP180 and BP230) and complement along the dermal-epidermal-junction is a hallmark of bullous pemphigoid and was shown to be important... (Randomized Controlled Trial)
Randomized Controlled Trial
Deposition of autoantibodies (α-BP180 and BP230) and complement along the dermal-epidermal-junction is a hallmark of bullous pemphigoid and was shown to be important for pathogenesis. Given the adverse effects of standard treatment (glucocorticoids, immunosuppressants), there is an unmet need for safe and effective therapies. In this phase 1 trial, we evaluated the safety and activity of BIVV009 (sutimlimab, previously TNT009), a targeted C1s inhibitor, in 10 subjects with active or past bullous pemphigoid (NCT02502903). Four weekly 60 mg/kg infusions of BIVV009 proved sufficient for inhibition of the classical complement pathway in all patients, as measured by CH50. C3c deposition along the dermal-epidermal junction was partially or completely abrogated in 4 of 5 patients, where it was present at baseline. BIVV009 was found to be safe and tolerable in this elderly population, with only mild to moderate adverse events reported (e.g., headache, fatigue). One serious adverse event (i.e., fatal cardiac decompensation) occurred at the end of the post-treatment observation period in an 84-year-old patient with a history of diabetes and heart failure, but was deemed unlikely to be related to the study drug. This trial provides the first results with a complement-targeting therapy in bullous pemphigoid, to our knowledge, and supports further studies on BIVV009's efficacy and safety in this population.
Topics: Aged; Aged, 80 and over; Autoantigens; Complement C3; Complement Pathway, Classical; Dermis; Dystonin; Epidermis; Female; Humans; Infusions, Intravenous; Male; Middle Aged; Non-Fibrillar Collagens; Pemphigoid, Bullous; Collagen Type XVII
PubMed: 31229501
DOI: 10.1016/j.jid.2019.04.025 -
Cell Jul 1999Sensory neurodegeneration occurs in mice defective in BPAG1, a gene encoding cytoskeletal linker proteins capable of anchoring neuronal intermediate filaments to actin...
Sensory neurodegeneration occurs in mice defective in BPAG1, a gene encoding cytoskeletal linker proteins capable of anchoring neuronal intermediate filaments to actin cytoskeleton. While BPAG1 null mice fail to anchor neurofilaments (NFs), BPAG1/NF null mice still degenerate in the absence of NFs. We report a novel neural splice form that lacks the actin-binding domain and instead binds and stabilizes microtubules. This interaction is functionally important; in mice and in vitro, neurons lacking BPAG1 display short, disorganized, and unstable microtubules defective in axonal transport. Ironically, BPAG1 neural isoforms represent microtubule-associated proteins that when absent lead to devastating consequences. Moreover, BPAG1 can functionally account for the extraordinary stability of axonal microtubules necessary for transport over long distances. Its isoforms interconnect all three cytoskeletal networks, a feature apparently central to neuronal survival.
Topics: Actin Cytoskeleton; Animals; Axonal Transport; Axons; Carrier Proteins; Cells, Cultured; Cytoskeletal Proteins; Desmoplakins; Dystonin; Mice; Mice, Knockout; Microfilament Proteins; Microscopy, Immunoelectron; Microtubules; Molecular Sequence Data; Nerve Tissue Proteins; Neurofilament Proteins; Neurons, Afferent; Protein Structure, Tertiary
PubMed: 10428034
DOI: 10.1016/s0092-8674(00)81017-x -
Structure (London, England : 1993) Jun 2019Mechanical stability of epithelia requires firm attachment to the basement membrane via hemidesmosomes. Dysfunction of hemidesmosomal proteins causes severe...
Mechanical stability of epithelia requires firm attachment to the basement membrane via hemidesmosomes. Dysfunction of hemidesmosomal proteins causes severe skin-blistering diseases. Two plakins, plectin and BP230 (BPAG1e), link the integrin α6β4 to intermediate filaments in epidermal hemidesmosomes. Here, we show that a linear sequence within the isoform-specific N-terminal region of BP230 binds to the third and fourth FnIII domains of β4. The crystal structure of the complex and mutagenesis analysis revealed that BP230 binds between the two domains of β4. BP230 induces closing of the two FnIII domains that are locked in place by an interdomain ionic clasp required for binding. Disruption of BP230-β4 binding prevents recruitment of BP230 to hemidesmosomes in human keratinocytes, revealing a key role of this interaction for hemidesmosome assembly. Phosphomimetic substitutions in β4 and BP230 destabilize the complex. Thus, our study provides insights into the architecture of hemidesmosomes and potential mechanisms of regulation.
Topics: Amino Acid Sequence; Basement Membrane; Binding Sites; Crystallography, X-Ray; Dystonin; Hemidesmosomes; Humans; Integrin alpha6beta4; Keratinocytes; Models, Molecular; Mutagenesis; Pemphigoid, Bullous; Protein Binding; Protein Domains; Sequence Homology, Amino Acid
PubMed: 31006587
DOI: 10.1016/j.str.2019.03.016 -
American Journal of Clinical Dermatology Jan 2021The clinical and immunological profile of patients with dipeptidyl peptidase-4 inhibitor (DPP4i)-associated bullous pemphigoid (BP) is inconsistent in the current...
More Severe Erosive Phenotype Despite Lower Circulating Autoantibody Levels in Dipeptidyl Peptidase-4 Inhibitor (DPP4i)-Associated Bullous Pemphigoid: A Retrospective Cohort Study.
BACKGROUND
The clinical and immunological profile of patients with dipeptidyl peptidase-4 inhibitor (DPP4i)-associated bullous pemphigoid (BP) is inconsistent in the current literature.
OBJECTIVES
The aims were to investigate the clinical and immunological features of patients with DPP4i-associated BP and to examine whether there are intraclass differences between different DPP4i agents.
METHODS
A retrospective cohort study was conducted, including all consecutive patients diagnosed with BP throughout the years 2009-2019 in a tertiary referral center.
RESULTS
The study encompassed 273 patients with BP (mean age at diagnosis 79.1 ± 9.9 years), of whom 24 (8.8%) were associated with DPP4i. Sitagliptin was the prescribed agent for 17 patients (70.8%), and vildagliptin was prescribed in seven patients (29.2%). Relative to other patients with BP, patients with DPP4i-associated BP had more prominent truncal involvement (95.8% vs. 73.9%; P = 0.017), greater erosion/blister Bullous Pemphigoid Disease Area Index (BPDAI) subscore (29.8 ± 17.4 vs. 20.6 ± 14.4; P = 0.018), and lower levels of anti-BP180 NC16A (279.2 ± 346.1 vs. 572.2 ± 1352.0 U/ml; P = 0.009) and anti-BP230 (25.5 ± 47.8 vs. 128.6 ± 302.9 U/ml; P = 0.009) antibodies. Relative to patients with sitagliptin-associated BP, those with vildagliptin-associated BP had a lower seropositivity rate (57.1% vs. 94.1%, P = 0.031) and lower levels (96.7 ± 139.0 vs. 354.5 ± 376.5; P = 0.023) of anti-BP180 NC16A antibodies, and tended to present with higher erosion/blister BPDAI subscore (36.3 ± 9.6 vs. 25.8 ± 19.7; P = 0.095).
CONCLUSIONS
DPP4i-associated BP is characterized by a more severe blistering and erosive presentation despite lower levels of typically pathogenic antibodies.
Topics: Aged; Aged, 80 and over; Autoantibodies; Autoantigens; Dipeptidyl-Peptidase IV Inhibitors; Dystonin; Female; Humans; Male; Middle Aged; Non-Fibrillar Collagens; Pemphigoid, Bullous; Retrospective Studies; Severity of Illness Index; Sitagliptin Phosphate; Skin; Vildagliptin; Collagen Type XVII
PubMed: 33026629
DOI: 10.1007/s40257-020-00563-7 -
The Journal of Investigative Dermatology Jan 1991The expression of basement membrane molecules and interstitial collagens in human hair follicle mesenchyme was studied by immunohistochemical staining of tissue sections...
The expression of basement membrane molecules and interstitial collagens in human hair follicle mesenchyme was studied by immunohistochemical staining of tissue sections and of cells cultured from dermal papillae. Type I and type III collagens were found in the dermal sheath and in the dermal papilla throughout the hair cycle. Laminin and type IV collagen were expressed at the outer root sheath basement membrane and in the extracellular matrix of the dermal papilla of anagen and catagen follicles. In telogen follicles, where the volume of the dermal papilla extracellular matrix is much reduced, outline staining of dermal papilla cells for laminin and type IV collagen was still apparent. Staining for bullous pemphigoid antigen was also seen at the outer root sheath basement membrane extending to the lower tip of the hair bulb. In anagen follicles, there was no staining for bullous pemphigoid antigen at the interface between hair bulb epithelium and the dermal papilla and no staining within the dermal papilla. However, linear staining for bullous pemphigoid antigen became continuous around hair follicle epithelium during catagen and telogen. Cells cultured from human dermal papillae also stained for interstitial collagens, type IV collagen and laminin. However, similar results were obtained when cultured dermal fibroblasts were stained with the same antibodies. The expression of basement membrane proteins in human dermal papillae resembles that seen in follicles from other mammalian species and suggests that this is relevant to dermal papilla function. Cultured dermal papilla cells express a similar pattern of interstitial collagens and basement membrane proteins to those seen in tissue sections but this finding is not specific to dermal papilla cells.
Topics: Antibodies, Monoclonal; Autoantigens; Basement Membrane; Carrier Proteins; Cells, Cultured; Collagen; Cytoskeletal Proteins; Dystonin; Hair; Humans; Laminin; Nerve Tissue Proteins; Non-Fibrillar Collagens; Pemphigoid, Bullous; Collagen Type XVII
PubMed: 1987302
DOI: 10.1111/1523-1747.ep12515907 -
American Journal of Transplantation :... Aug 2007Allograft(dagger) transplant outcome, rejection or tolerance, depends upon striking a balance between the pertinent cytopathic and regulatory T cells. The drug...
Allograft(dagger) transplant outcome, rejection or tolerance, depends upon striking a balance between the pertinent cytopathic and regulatory T cells. The drug cyclosporine is a widely used immunosuppressive agent among transplant recipients. Previous studies have demonstrated that cyclosporine blocks apoptosis of activated T cells and the ability of costimulation blockade based regimens to create peripheral transplant tolerance. We now test the hypothesis that the mechanism by which cyclosporine blocks tolerance induction is IL-2 dependent, and linked to a detrimental effect upon T(reg) function. Our study demonstrates that cyclosporine blocks IL-2 gene expression and activation induced cell death (AICD) of alloreactive T effector cells. We also show that cyclosporine abolishes the beneficial effects of a donor specific transfusion (DST) plus anti-CD154 monoclonal antibody (alpha CD154) regimen on enhanced T(regs) function and allograft tolerance induction. Interestingly, provision of IL-2/Fc, a long-lived form of IL-2, completely reverses the detrimental effects of this adjunctive cyclosporine treatment on AICD of alloreactive T effectors, T(regs) function and tolerance induction. Furthermore, in a MHC mismatched islet allograft model, the combination of cyclosporine with IL-2/Fc permitted long-term allograft survival and induced alloantigen specific allograft tolerance. The combination of IL-2/Fc and cyclosporine treatment may provide a new clinical strategy to promote transplant tolerance.
Topics: Animals; Apoptosis; CD40 Ligand; Carrier Proteins; Cell Proliferation; Cyclosporine; Cytoskeletal Proteins; Disease Models, Animal; Dystonin; Gene Expression; Graft Rejection; Graft Survival; Immunosuppressive Agents; Interleukin-2; Islets of Langerhans Transplantation; Lymphocyte Activation; Male; Mice; Mice, Inbred BALB C; Mice, Inbred C3H; Mice, Inbred C57BL; Mice, Inbred DBA; Nerve Tissue Proteins; Polymerase Chain Reaction; Prognosis; RNA; T-Lymphocytes; Transplantation, Homologous
PubMed: 17617853
DOI: 10.1111/j.1600-6143.2007.01881.x -
Acta Dermato-venereologica 2000Some patients with scabies develop bullae concomitantly with, or subsequently after, the occurrence of scabetic lesions. Although several immunofluorescence studies have... (Review)
Review
Some patients with scabies develop bullae concomitantly with, or subsequently after, the occurrence of scabetic lesions. Although several immunofluorescence studies have demonstrated immunoglobulin deposition in the basement membrane zone of bullous lesions, it remained unclear whether these antibodies are directed to bullous pemphigoid antigens. We clearly show that two scabetic patients with bullous eruptions had circulating antibodies against BP180 and/or BP230 as determined by Western blotting analysis. This is the first report to demonstrate that at least some of the bullous eruptions occurring in scabetics are true bullous pemphigoid.
Topics: Aged; Autoantibodies; Autoantigens; Blotting, Western; Carrier Proteins; Collagen; Cytoskeletal Proteins; Dystonin; Humans; Male; Nerve Tissue Proteins; Non-Fibrillar Collagens; Pemphigoid, Bullous; Scabies; Collagen Type XVII
PubMed: 11028862
DOI: 10.1080/000155500750012171