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ELife May 2022Human myelin disorders are commonly studied in mouse models. Since both clades evolutionarily diverged approximately 85 million years ago, it is critical to know to what...
Human myelin disorders are commonly studied in mouse models. Since both clades evolutionarily diverged approximately 85 million years ago, it is critical to know to what extent the myelin protein composition has remained similar. Here, we use quantitative proteomics to analyze myelin purified from human white matter and find that the relative abundance of the structural myelin proteins PLP, MBP, CNP, and SEPTIN8 correlates well with that in C57Bl/6N mice. Conversely, multiple other proteins were identified exclusively or predominantly in human or mouse myelin. This is exemplified by peripheral myelin protein 2 (PMP2), which was specific to human central nervous system myelin, while tetraspanin-2 (TSPAN2) and connexin-29 (CX29/GJC3) were confined to mouse myelin. Assessing published scRNA-seq-datasets, human and mouse oligodendrocytes display well-correlating transcriptome profiles but divergent expression of distinct genes, including and . A searchable web interface is accessible via www.mpinat.mpg.de/myelin. Species-dependent diversity of oligodendroglial mRNA expression and myelin protein composition can be informative when translating from mouse models to humans.
Topics: Animals; Connexins; Humans; Mice; Mice, Inbred Strains; Myelin Proteins; Myelin Proteolipid Protein; Myelin Sheath; Nerve Tissue Proteins; Oligodendroglia; Proteome; Tetraspanins; Transcriptome
PubMed: 35543322
DOI: 10.7554/eLife.77019 -
Human Molecular Genetics Nov 2021Oligodendrocytes (OLs) produce myelin in the central nervous system (CNS), which accelerates the propagation of action potentials and supports axonal integrity. As a...
Oligodendrocytes (OLs) produce myelin in the central nervous system (CNS), which accelerates the propagation of action potentials and supports axonal integrity. As a major component of CNS myelin, proteolipid protein 1 (Plp1) is indispensable for the axon-supportive function of myelin. Notably, this function requires the continuous high-level expression of Plp1 in OLs. Equally important is the controlled expression of Plp1, as illustrated by Pelizaeus-Merzbacher disease for which the most common cause is PLP1 overexpression. Despite a decade-long search, promoter-distal OL enhancers that govern Plp1 remain elusive. We have recently developed an innovative method that maps promoter-distal enhancers to genes in a principled manner. Here, we applied it to Plp1, uncovering two OL enhancers for it (termed Plp1-E1 and Plp1-E2). Remarkably, clustered regularly interspaced short palindromic repeats (CRISPR) interference epigenome editing showed that Plp1-E1 and Plp1-E2 do not regulate two genes in their vicinity, highlighting their exquisite specificity to Plp1. Assay for transposase-accessible chromatin with high-throughput sequencing (ATAC-seq) and chromatin immunoprecipitation with high-throughput sequencing (ChIP-seq) data show that Plp1-E1 and Plp1-E2 are OL-specific enhancers that are conserved among human, mouse and rat. Hi-C data reveal that the physical interactions between Plp1-E1/2 and PLP1 are among the strongest in OLs and specific to OLs. We also show that Myrf, a master regulator of OL development, acts on Plp1-E1 and Plp1-E2 to promote Plp1 expression.
Topics: Animals; Base Sequence; Binding Sites; CRISPR-Cas Systems; Chromatin Immunoprecipitation Sequencing; Chromosome Mapping; DNA-Binding Proteins; Enhancer Elements, Genetic; Gene Expression Regulation; Humans; Membrane Proteins; Mice; Myelin Proteolipid Protein; Nucleotide Motifs; Oligodendroglia; Promoter Regions, Genetic; Transcription Factors
PubMed: 34230963
DOI: 10.1093/hmg/ddab184 -
Journal of Translational Medicine Mar 2023Cancer/testis antigens (CTAs) participate in the regulation of malignant biological behaviors in breast cancer. However, the function and mechanism of KK-LC-1, a member...
BACKGROUND
Cancer/testis antigens (CTAs) participate in the regulation of malignant biological behaviors in breast cancer. However, the function and mechanism of KK-LC-1, a member of the CTA family, in breast cancer are still unclear.
METHODS
Bioinformatic tools, immunohistochemistry, and western blotting were utilized to detect the expression of KK-LC-1 in breast cancer and to explore the prognostic effect of KK-LC-1 expression in breast cancer patients. Cell function assays, animal assays, and next-generation sequencing were utilized to explore the function and mechanism of KK-LC-1 in the malignant biological behaviors of triple-negative breast cancer. Small molecular compounds targeting KK-LC-1 were also screened and drug susceptibility testing was performed.
RESULTS
KK-LC-1 was significantly highly expressed in triple-negative breast cancer tissues than in normal breast tissues. KK-LC-1 high expression was related to poor survival outcomes in patients with breast cancer. In vitro studies suggested that KK-LC-1 silencing can inhibit triple-negative breast cancer cell proliferation, invasion, migration, and scratch healing ability, increase cell apoptosis ratio, and arrest the cell cycle in the G0-G1 phase. In vivo studies have suggested that KK-LC-1 silencing decreases tumor weight and volume in nude mice. Results showed that KK-CL-1 can regulate the malignant biological behaviors of triple-negative breast cancer via the MAL2/MUC1-C/PI3K/AKT/mTOR pathway. The small-molecule compound Z839878730 had excellent KK-LC-1 targeting ability and cancer cell killing ability. The EC value was 9.7 μM for MDA-MB-231 cells and 13.67 µM for MDA-MB-468 cells. Besides, Z839878730 has little tumor-killing effect on human normal mammary epithelial cells MCF10A and can inhibit the malignant biological behaviors of triple-negative breast cancer cells by MAL2/MUC1-C/PI3K/AKT/mTOR pathway.
CONCLUSIONS
Our findings suggest that KK-LC-1 may serve as a novel therapeutic target for triple-negative breast cancer. Z839878730, which targets KK-LC-1, presents a new path for breast cancer clinical treatment.
Topics: Male; Animals; Mice; Humans; Triple Negative Breast Neoplasms; Proto-Oncogene Proteins c-akt; Mice, Nude; Phosphatidylinositol 3-Kinases; Microbial Sensitivity Tests; Mycobacterium tuberculosis; TOR Serine-Threonine Kinases; Antigens, Neoplasm; Cell Proliferation; Cell Line, Tumor; Cell Movement; Apoptosis; Myelin and Lymphocyte-Associated Proteolipid Proteins
PubMed: 36895039
DOI: 10.1186/s12967-023-04030-9 -
American Journal of Physiology. Cell... Mar 2022Sarcolipin (SLN) is a small regulatory protein that inhibits the sarco(endo)plasmic reticulum Ca-ATPase (SERCA) pump. When bound to SERCA, SLN reduces the apparent Ca... (Review)
Review
Sarcolipin (SLN) is a small regulatory protein that inhibits the sarco(endo)plasmic reticulum Ca-ATPase (SERCA) pump. When bound to SERCA, SLN reduces the apparent Ca affinity of SERCA and uncouples SERCA Ca transport from its ATP consumption. As such, SLN plays a direct role in altering skeletal muscle relaxation and energy expenditure. Interestingly, the expression of SLN is dynamic during times of muscle adaptation, in that large increases in SLN content are found in response to development, atrophy, overload, and disease. Several groups have suggested that increases in SLN, especially in dystrophic muscle, are deleterious as it may reduce muscle function and exacerbate already abhorrent intracellular Ca levels. However, there is also significant evidence to show that increased SLN content is a beneficial adaptive mechanism that protects the SERCA pump and activates Ca signaling and adaptive remodeling during times of cell stress. In this review, we first discuss the role for SLN in healthy muscle during both development and overload, where SLN has been shown to activate Ca signaling to promote mitochondrial biogenesis, fiber-type shifts, and muscle hypertrophy. Then, with respect to muscle disease, we summarize the discrepancies in the literature as to whether SLN upregulation is adaptive or maladaptive in nature. This review is the first to offer the concept of SLN hormesis in muscle disease, wherein both too much and too little SLN are detrimental to muscle health. Finally, the underlying mechanisms which activate SLN upregulation are discussed, specifically acknowledging a potential positive feedback loop between SLN and Ca signaling molecules.
Topics: Animals; Calcium Signaling; Humans; Mitochondria, Muscle; Muscle Development; Muscle Proteins; Muscle, Skeletal; Muscular Atrophy; Muscular Dystrophies; Proteolipids; Sarcoplasmic Reticulum Calcium-Transporting ATPases
PubMed: 35044855
DOI: 10.1152/ajpcell.00198.2021 -
Aging Nov 2023The abnormality of surfactant protein C (SFTPC) has been linked to the development of a number of interstitial lung diseases, according to mounting evidence....
The abnormality of surfactant protein C (SFTPC) has been linked to the development of a number of interstitial lung diseases, according to mounting evidence. Nonetheless, the function and mechanism of SFTPC in the biological progression of lung adenocarcinoma (LUAD) remain unclear. Analysis of public datasets and testing of clinical samples suggested that SFTPC expression was abnormally low in LUAD, which was associated with the onset and poor prognosis of LUAD. The SFTPC-related risk score was derived using least absolute shrinkage and selection operator Cox regression as well as multivariate Cox regression. The risk score was highly correlated with tumor purity and tumor mutation burden, and it could serve as an independent prognostic indicator for LUAD. Low-risk LUAD patients may benefit more from CTLA-4 or/and PD-1 inhibitors. Overall, the risk score is useful for LUAD patient prognostication and treatment guidance. Moreover, and experiments demonstrated that SFTPC inhibits the proliferation of LUAD by inhibiting PI3K/AKT/mTOR signaling transduction. These results reveal the molecular mechanism by which SFTPC inhibits the proliferation of LUAD and suggest that SFTPC could be a new therapeutic target for LUAD.
Topics: Humans; Proto-Oncogene Proteins c-akt; Phosphatidylinositol 3-Kinases; Lung Neoplasms; Cell Proliferation; Adenocarcinoma of Lung; TOR Serine-Threonine Kinases; Gene Expression Regulation, Neoplastic; Pulmonary Surfactant-Associated Protein C
PubMed: 37955668
DOI: 10.18632/aging.205191 -
Frontiers in Chemistry 2022Myelin is a modified cell membrane that forms a multilayer sheath around the axon. It retains the main characteristics of biological membranes, such as lipid bilayer,... (Review)
Review
Myelin is a modified cell membrane that forms a multilayer sheath around the axon. It retains the main characteristics of biological membranes, such as lipid bilayer, but differs from them in several important respects. In this review, we focus on aspects of myelin composition that are peculiar to this structure and differentiate it from the more conventional cell membranes, with special attention to its constituent lipid components and several of the most common and important myelin proteins: myelin basic protein, proteolipid protein, and myelin protein zero. We also discuss the many-fold functions of myelin, which include reliable electrical insulation of axons to ensure rapid propagation of nerve impulses, provision of trophic support along the axon and organization of the unmyelinated nodes of Ranvier, as well as the relationship between myelin biology and neurologic disease such as multiple sclerosis. We conclude with a brief history of discovery in the field and outline questions for future research.
PubMed: 36896314
DOI: 10.3389/fchem.2022.1041961 -
Molekuliarnaia Biologiia 2021The mechanisms involved in the origin and development of malignant and neurodegenerative diseases are an important area of modern biomedicine. A crucial task is to...
The mechanisms involved in the origin and development of malignant and neurodegenerative diseases are an important area of modern biomedicine. A crucial task is to identify new molecular markers that are associated with rearrangements of intracellular signaling and can be used for prognosis and the development of effective treatment approaches. The proteolipid plasmolipin (PLLP) is a possible marker. PLLP is a main component of the myelin sheath and plays an important role in the development and normal function of the nervous system. PLLP is involved in intracellular transport, lipid raft formation, and Notch signaling. PLLP is presumably involved in various disorders, such as cancer, schizophrenia, Alzheimer's disease, and type 2 diabetes mellitus. PLLP and its homologs were identified as possible virus entry receptors. The review summarizes the data on the PLLP structure, normal functions, and role in diseases.
Topics: Diabetes Mellitus, Type 2; Humans; Myelin Sheath; Myelin and Lymphocyte-Associated Proteolipid Proteins; Nerve Tissue Proteins; Proteolipids
PubMed: 34837695
DOI: 10.31857/S0026898421060112 -
International Journal of Molecular... Jul 2020Exosomes (EXs) and extracellular microvesicles (EMVs) represent a diverse assortment of plasma membrane-derived nanovesicles, 30-1000 nm in diameter, released by all... (Review)
Review
Exosomes (EXs) and extracellular microvesicles (EMVs) represent a diverse assortment of plasma membrane-derived nanovesicles, 30-1000 nm in diameter, released by all cell lineages of the central nervous system (CNS). They are examples of a very active and dynamic form of extracellular communication and the conveyance of biological information transfer essential to maintain homeostatic neurological functions and contain complex molecular cargoes representative of the cytoplasm of their cells of origin. These molecular cargoes include various mixtures of proteins, lipids, proteolipids, cytokines, chemokines, carbohydrates, microRNAs (miRNA) and messenger RNAs (mRNA) and other components, including end-stage neurotoxic and pathogenic metabolic products, such as amyloid beta (Aβ) peptides. Brain microglia, for example, respond to both acute CNS injuries and degenerative diseases with complex reactions via the induction of a pro-inflammatory phenotype, and secrete EXs and EMVs enriched in selective pathogenic microRNAs (miRNAs) such as miRNA-34a, miRNA-125b, miRNA-146a, miRNA-155, and others that are known to promote neuro-inflammation, induce complement activation, disrupt innate-immune signaling and deregulate the expression of neuron-specific phosphoproteins involved in neurotropism and synaptic signaling. This communication will review our current understanding of the trafficking of miRNA-containing EXs and EMVs from astrocytes and "activated pro-inflammatory" microglia to target neurons in neurodegenerative diseases with an emphasis on Alzheimer's disease wherever possible.
Topics: Alzheimer Disease; Amyloid beta-Peptides; Astrocytes; Biological Transport; Cell-Derived Microparticles; Exosomes; Extracellular Vesicles; Humans; Inflammation; MicroRNAs; Microglia; Neuroglia; Neurons
PubMed: 32708414
DOI: 10.3390/ijms21145078 -
Biochemical Society Transactions Aug 2020Membrane proteins (MPs) are the gatekeepers between different biological compartments separated by lipid bilayers. Being receptors, channels, transporters, or primary... (Review)
Review
Membrane proteins (MPs) are the gatekeepers between different biological compartments separated by lipid bilayers. Being receptors, channels, transporters, or primary pumps, they fulfill a wide variety of cellular functions and their importance is reflected in the increasing number of drugs that target MPs. Functional studies of MPs within a native cellular context, however, is difficult due to the innate complexity of the densely packed membranes. Over the past decades, detergent-based extraction and purification of MPs and their reconstitution into lipid mimetic systems has been a very powerful tool to simplify the experimental system. In this review, we focus on proteoliposomes that have become an indispensable experimental system for enzymes with a vectorial function, including many of the here described energy transducing MPs. We first address long standing questions on the difficulty of successful reconstitution and controlled orientation of MPs into liposomes. A special emphasis is given on coreconstitution of several MPs into the same bilayer. Second, we discuss recent progress in the development of fluorescent dyes that offer sensitive detection with high temporal resolution. Finally, we briefly cover the use of giant unilamellar vesicles for the investigation of complex enzymatic cascades, a very promising experimental tool considering our increasing knowledge of the interplay of different cellular components.
Topics: Biological Transport; Lipid Bilayers; Membrane Proteins; Proteolipids
PubMed: 32830854
DOI: 10.1042/BST20190966 -
Plant Physiology Apr 2020Plasma membranes provide a highly selective environment for a large number of transmembrane and membrane-associated proteins. Whereas lateral movement of proteins in... (Review)
Review
Plasma membranes provide a highly selective environment for a large number of transmembrane and membrane-associated proteins. Whereas lateral movement of proteins in this lipid bilayer is possible, it is rather limited in turgid and cell wall-shielded plant cells. However, membrane-resident signaling processes occur on subsecond scales that cannot be explained by simple diffusion models. Accordingly, several receptors and other membrane-associated proteins are organized and functional in membrane nanodomains. Although the general presence of membrane nanodomains has become widely accepted as fact, fundamental functional aspects, the roles of individual lipid species and their interplay with proteins, and aspects of nanodomain maintenance and persistence remain poorly understood. Here, we review the current knowledge of nanodomain organization and function, with a particular focus on signaling processes involving proteins, lipids, and their interactions. Furthermore, we propose new and hypothetical aspects of plant membrane biology that we consider important for future research.
Topics: Cell Membrane; Membrane Microdomains; Models, Biological; Proteolipids; Signal Transduction
PubMed: 31857424
DOI: 10.1104/pp.19.01349