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Frontiers in Physiology 2023[This corrects the article DOI: 10.3389/fphys.2023.1205493.].
Corrigendum: Variability of extracellular vesicle release during storage of red blood cell concentrates is associated with differential membrane alterations, including loss of cholesterol-enriched domains.
[This corrects the article DOI: 10.3389/fphys.2023.1205493.].
PubMed: 37795268
DOI: 10.3389/fphys.2023.1291218 -
ELife Sep 2023The acquisition of distinct branch sizes and shapes is a central aspect in tubular organ morphogenesis and function. In the airway tree, the interplay of apical...
The acquisition of distinct branch sizes and shapes is a central aspect in tubular organ morphogenesis and function. In the airway tree, the interplay of apical extracellular matrix (ECM) components with the underlying membrane and cytoskeleton controls tube elongation, but the link between ECM composition with apical membrane morphogenesis and tube size regulation is elusive. Here, we characterized Emp (epithelial membrane protein), a CD36 homolog belonging to the scavenger receptor class B protein family. mutant embryos fail to internalize the luminal chitin deacetylases Serp and Verm at the final stages of airway maturation and die at hatching with liquid filled airways. Emp localizes in apical epithelial membranes and shows cargo selectivity for LDLr-domain containing proteins. mutants also display over elongated tracheal tubes with increased levels of the apical proteins Crb, DE-cad, and phosphorylated Src (p-Src). We show that Emp associates with and organizes the βH-Spectrin cytoskeleton and is itself confined by apical F-actin bundles. Overexpression or loss of its cargo protein Serp lead to abnormal apical accumulations of Emp and perturbations in p-Src levels. We propose that during morphogenesis, Emp senses and responds to luminal cargo levels by initiating apical membrane endocytosis along the longitudinal tube axis and thereby restricts airway elongation.
Topics: Animals; Drosophila melanogaster; Drosophila Proteins; Endocytosis; Morphogenesis; Receptors, Scavenger; Trachea
PubMed: 37706489
DOI: 10.7554/eLife.84974 -
Cells Aug 2023Fibroblasts in the heart, traditionally recognized as interstitial cells, have long been overlooked in the study of cardiac physiology and pathology [...].
βIV-Spectrin in Cardiac Fibroblasts: Implications for Fibrosis and Therapeutic Targeting in Cardiac Diseases. Comment on Nassal et al. Spectrin-Based Regulation of Cardiac Fibroblast Cell-Cell Communication. 2023, , 748.
Fibroblasts in the heart, traditionally recognized as interstitial cells, have long been overlooked in the study of cardiac physiology and pathology [...].
Topics: Humans; Spectrin; Heart Diseases; Fibroblasts; Cell Communication; Fibrosis
PubMed: 37681918
DOI: 10.3390/cells12172186 -
Cancer Medicine Sep 2023Tumor-associated angiogenesis mediates the growth and metastasis of most solid cancers. Targeted therapies of the VEGF pathways can effectively block these processes but...
BACKGROUND
Tumor-associated angiogenesis mediates the growth and metastasis of most solid cancers. Targeted therapies of the VEGF pathways can effectively block these processes but often fail to provide lasting benefits due to acquired resistance and complications.
RESULTS
Recently, we discovered β -spectrin as a powerful regulator of angiogenesis and potential new target. We previously reported that β -spectrin is dynamically expressed in endothelial cells (EC) to induce VEGFR2 protein turnover during development. Here, we explored how β -spectrin influences the tumor vasculature using the murine B16 melanoma model and determined that loss of EC-specific β -spectrin dramatically promotes tumor growth and metastasis. Intraperitoneally injected B16 cells formed larger tumors with increased tumor vessel density and greater propensity for metastatic spread particularly to the chest cavity and lung compared to control mice. These results support β -spectrin as a key regulator of tumor angiogenesis and a viable vascular target in cancer.
Topics: Animals; Mice; Endothelial Cells; Melanoma, Experimental; Neovascularization, Pathologic; Spectrin
PubMed: 37680049
DOI: 10.1002/cam4.6522 -
Clinical and Translational Medicine Sep 2023The roles of circRNA and N6-methyladenosine (m A) methylation in Crohn's disease (CD) have drawn much attention. Therefore, this investigation aimed to discover how the...
BACKGROUND
The roles of circRNA and N6-methyladenosine (m A) methylation in Crohn's disease (CD) have drawn much attention. Therefore, this investigation aimed to discover how the m A modification of circRNAs contributes to CD progression.
METHODS
The study performed circRNA sequencing on colon samples from four CD patients and four normal controls (NCs) to screen for dysregulated circRNAs. Quantitative real-time polymerase chain reaction (qRT-PCR) was performed to validate the candidate circRNA expression and determine its correlation to CD-associated inflammatory indicators. In vivo and in vitro investigations were conducted to examine the functions and pathways of circPRKAR1B in CD, besides investigating the m A modification role in circRNA expression modulation.
RESULTS
The RNA-seq revealed that hsa_circ_0008039 (circPRKAR1B) was the most significant upregulated circRNA and was identified as the candidate circRNA for further examinations. Relative circPRKAR1B expression was significantly upregulated in CD colon tissues and closely related to CD-associated inflammatory indices. The circPRKAR1B expression and function were regulated by methyltransferase-like 3 (METTL3)-mediated m A methylation. In vitro studies indicated that circPRKAR1B promoted pyroptosis mediated by NLRP3 inflammasome (NLRP3; nucleotide-binding oligomerization domain, leucine-rich repeat and pyrin domain-containing 3) and impaired autophagy by interacting with the RNA-binding protein (RBP) SPTBN1, (SPTBN1; spectrin beta, non-erythrocytic 1). The in vivo investigations revealed the treatment effects of si-circPRKAR1B and si-METTL3 in colitis models of IL-10-deficient mice.
CONCLUSION
Our study reveals that METTL3-mediated m A modification of circPRKAR1B promotes Crohn's colitis by aggravating NLRP3 inflammasome-mediated pyroptosis via autophagy impairment in colonic epithelial cells.
Topics: Animals; Mice; Autophagy; Colitis; Crohn Disease; Inflammasomes; NLR Family, Pyrin Domain-Containing 3 Protein; Pyroptosis; RNA, Circular
PubMed: 37679886
DOI: 10.1002/ctm2.1405 -
Research Square Aug 2023Force transmission at integrin-based adhesions is important for cell migration and mechanosensing. Talin is an essential focal adhesion (FA) protein that links F-actin...
Force transmission at integrin-based adhesions is important for cell migration and mechanosensing. Talin is an essential focal adhesion (FA) protein that links F-actin to integrins. F-actin constantly moves on FAs, yet how Talin simultaneously maintains the connection to F-actin and transmits forces to integrins remains unclear. Here we show a critical role of dynamic Talin unfolding in force transmission. Using single-molecule speckle microscopy, we found that the majority of Talin are bound only to either F-actin or the substrate, whereas 4.1% of Talin is linked to both structures via elastic transient clutch. By reconstituting Talin knockdown cells with Talin chimeric mutants, in which the Talin rod subdomains are replaced with the stretchable β-spectrin repeats, we show that the stretchable property is critical for force transmission. Simulations suggest that unfolding of the Talin rod subdomains increases in the linkage duration and work at FAs. This study reveals a new mode of force transmission, in which stochastic molecular stretching bridges two cellular structures moving at different speeds.
PubMed: 37674715
DOI: 10.21203/rs.3.rs-3254213/v1 -
Biology Open Sep 2023Robust expression of shortened, functional dystrophin provided impetus to develop adeno-associated virus (AAV)-based constructs for clinical application. Because several...
Robust expression of shortened, functional dystrophin provided impetus to develop adeno-associated virus (AAV)-based constructs for clinical application. Because several cassettes are being tested in clinical trials, this study compared the efficacies of four shortened dystrophin-promoter combinations with implications for outcomes in clinical trials: MHCK7 or MCK promoter with a shortened dystrophin transgene containing the N-terminus and spectrin repeats R1, R2, R3 and R24 (rAAVrh74.MHCK7.micro-dystrophin and rAAVrh74.MCK.micro-dystrophin, respectively); shortened dystrophin construct containing the neuronal nitric oxide (nNOS) binding site (rAAVrh74.MHCK7.DV.mini-dystrophin); and shortened dystrophin containing the C-terminus (rAAVrh74.MHCK7.micro-dystrophin.Cterm). Functional and histological benefit were examined at 4 weeks following intramuscular delivery in mdx mice. rAAVrh74.MHCK7.micro-dystrophin provided the most robust transgene expression and significantly increased specific force output in the tibialis anterior muscle. Muscle environment was normalized (i.e. reductions in central nucleation), indicating functional and histological advantages of rAAVrh74.MHCK7.micro-dystrophin. Thus, promoter choice and transgene design are critical for optimal dystrophin expression/distribution for maximal functional improvement.
Topics: Mice; Animals; Dystrophin; Muscular Dystrophy, Duchenne; Mice, Inbred mdx; Dependovirus; Actin Cytoskeleton; Disease Models, Animal
PubMed: 37670674
DOI: 10.1242/bio.059797 -
BioRxiv : the Preprint Server For... Sep 2023Neuronal connectivity is regulated during normal brain development with the arrangement of spines and synapses being dependent on the morphology of dendrites. Further,...
Neuronal connectivity is regulated during normal brain development with the arrangement of spines and synapses being dependent on the morphology of dendrites. Further, in multiple neurodevelopmental and aging disorders, disruptions of dendrite formation or shaping is associated with atypical neuronal connectivity. We showed previously that Pdlim5 binds delta-catenin and promotes dendrite branching (Baumert et al., J Cell Biol 2020). We report here that Pdlim5 interacts with PalmD, a protein previously suggested by others to interact with the cytoskeleton (e.g., via adducin/ spectrin) and to regulate membrane shaping. Functionally, the knockdown of PalmD or Pdlim5 in rat primary hippocampal neurons dramatically reduces branching and conversely, PalmD exogenous expression promotes dendrite branching as does Pdlim5. Further, we show that effects of each protein are dependent on the presence of the other. In summary, using primary rat hippocampal neurons we reveal the contributions of a novel Pdlim5:PalmD protein complex, composed of functionally inter-dependent components responsible for shaping neuronal dendrites.
PubMed: 37662414
DOI: 10.1101/2023.08.22.553334 -
Cells Aug 2023Spinocerebellar ataxia type 5 (SCA5) is a neurodegenerative disease caused by mutations in the gene encoding the cytoskeletal protein β-III-spectrin. Previously, we...
Spinocerebellar ataxia type 5 (SCA5) is a neurodegenerative disease caused by mutations in the gene encoding the cytoskeletal protein β-III-spectrin. Previously, we demonstrated that a L253P missense mutation, localizing to the β-III-spectrin actin-binding domain (ABD), causes increased actin-binding affinity. Here we investigate the molecular consequences of nine additional ABD-localized, SCA5 missense mutations: V58M, K61E, T62I, K65E, F160C, D255G, T271I, Y272H, and H278R. We show that all of the mutations, similar to L253P, are positioned at or near the interface of the two calponin homology subdomains (CH1 and CH2) comprising the ABD. Using biochemical and biophysical approaches, we demonstrate that the mutant ABD proteins can attain a well-folded state. However, thermal denaturation studies show that all nine mutations are destabilizing, suggesting a structural disruption at the CH1-CH2 interface. Importantly, all nine mutations cause increased actin binding. The mutant actin-binding affinities vary greatly, and none of the nine mutations increase actin-binding affinity as much as L253P. ABD mutations causing high-affinity actin binding, with the notable exception of L253P, appear to be associated with an early age of symptom onset. Altogether, the data indicate that increased actin-binding affinity is a shared molecular consequence of numerous SCA5 mutations, which has important therapeutic implications.
Topics: Humans; Actins; Spectrin; Mutation; Mutation, Missense; Spinocerebellar Ataxias
PubMed: 37626910
DOI: 10.3390/cells12162100 -
Journal of Molecular Cell Biology Jan 2024Microtubule networks support many cellular processes and exhibit a highly ordered architecture. However, due to the limited axial resolution of conventional light...
Microtubule networks support many cellular processes and exhibit a highly ordered architecture. However, due to the limited axial resolution of conventional light microscopy, the structural features of these networks cannot be resolved in three-dimensional (3D) space. Here, we used customized ultra-high-resolution interferometric single-molecule localization microscopy to characterize the microtubule networks in Caco2 cells. We found that the calmodulin-regulated spectrin-associated proteins (CAMSAPs) localize at a portion of microtubule intersections. Further investigation showed that depletion of CAMSAP2 and CAMSAP3 leads to the narrowing of the inter-microtubule distance. Mechanistically, CAMSAPs recognize microtubule defects, which often occur near microtubule intersections, and then recruit katanin to remove the damaged microtubules. Therefore, the CAMSAP-katanin complex is a regulatory module for the distance between microtubules. Taken together, our results characterize the architecture of cellular microtubule networks in high resolution and provide molecular insights into how the 3D structure of microtubule networks is controlled.
Topics: Microtubules; Humans; Caco-2 Cells; Microtubule-Associated Proteins; Katanin
PubMed: 37567766
DOI: 10.1093/jmcb/mjad050