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  1. Article ; Online: Evaluation of Connexin Hemichannel Activity In Vivo.

    Acosta, Francisca M / Riquelme, Manuel A / Gu, Sumin / Jiang, Jean X

    Methods in molecular biology (Clifton, N.J.)

    2024  Volume 2801, Page(s) 111–124

    Abstract: Connexin hemichannels (Cx HCs) are hexameric structures at the cell plasma membrane, whose function as membrane transport proteins allows for the passive flow of small hydrophilic molecules and ions (≤1 kDa) between the cytosol and the extracellular ... ...

    Abstract Connexin hemichannels (Cx HCs) are hexameric structures at the cell plasma membrane, whose function as membrane transport proteins allows for the passive flow of small hydrophilic molecules and ions (≤1 kDa) between the cytosol and the extracellular environment. Activation of Cx HCs is highly dependent on pathological conditions. HC activity provokes changes in the microenvironment, inducing the dissemination of signaling molecules in both an autocrine and paracrine manner. Given the elicitation of a variety of signaling pathways, and assortment of Cx species and dispersion throughout the body, Cx HCs have been implicated in a range of processes such as cell proliferation, differentiation, cell death, and tissue modeling and remodeling. While studying the expression and localization of Cx HCs can be done using traditional laboratory techniques, such as immunoblot analysis, measuring the functionality/activity of the HCs requires a more explicit methodology and is essential for determining Cx-mediated physiological changes. The study of Cx HC function/activity has focused mainly on in vitro measurements through electrophysiological characterization or, more commonly, using HC-permeable dye uptake studies. Here, we describe the use of dye uptake to measure Cx HC activity in vivo using mechanically stimulated osteocytic Cx43 HCs with Evans blue dye as our model.
    MeSH term(s) Connexins/metabolism ; Cell Membrane/metabolism ; Signal Transduction ; Electrophysiological Phenomena
    Chemical Substances Connexins
    Language English
    Publishing date 2024-04-05
    Publishing country United States
    Document type Journal Article
    ISSN 1940-6029
    ISSN (online) 1940-6029
    DOI 10.1007/978-1-0716-3842-2_9
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article ; Online: The Role of Gap Junctions Dysfunction in the Development of Cataracts: From Loss of Cell-to-Cell Transfer to Blurred Vision-Review.

    Ek-Vitorin, Jose F / Jiang, Jean X

    Bioelectricity

    2023  Volume 5, Issue 3, Page(s) 164–172

    Abstract: Mutations of lens connexins are linked to congenital cataracts. However, the role of connexin mutations in the development of age-related lens opacification remains largely unknown. Here, we present a focused review of the literature on lens organization ...

    Abstract Mutations of lens connexins are linked to congenital cataracts. However, the role of connexin mutations in the development of age-related lens opacification remains largely unknown. Here, we present a focused review of the literature on lens organization and factors associated with cataract development. Several lines of evidence indicate that disturbances of the lens circulation by dysfunctional connexin channels, and/or accumulation of protein damage due to oxidative stress, are key factors in cataract development. Phosphorylation by protein kinase A improves the permeability of connexins channels to small molecules and mitigates the lens clouding induced by oxidative stress. We conclude (1) that connexin channels are central to the lens circulation and (2) that their permeability to antioxidant molecules contributes to the maintenance of lens transparency.
    Language English
    Publishing date 2023-09-12
    Publishing country United States
    Document type Journal Article ; Review
    ISSN 2576-3113
    ISSN (online) 2576-3113
    DOI 10.1089/bioe.2023.0025
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article ; Online: Gap Junctions or Hemichannel-Dependent and Independent Roles of Connexins in Fibrosis, Epithelial-Mesenchymal Transitions, and Wound Healing.

    Li, Yuting / Acosta, Francisca M / Jiang, Jean X

    Biomolecules

    2023  Volume 13, Issue 12

    Abstract: Fibrosis initially appears as a normal response to damage, where activated fibroblasts produce large amounts of the extracellular matrix (ECM) during the wound healing process to assist in the repair of injured tissue. However, the excessive accumulation ...

    Abstract Fibrosis initially appears as a normal response to damage, where activated fibroblasts produce large amounts of the extracellular matrix (ECM) during the wound healing process to assist in the repair of injured tissue. However, the excessive accumulation of the ECM, unresolved by remodeling mechanisms, leads to organ dysfunction. Connexins, a family of transmembrane channel proteins, are widely recognized for their major roles in fibrosis, the epithelial-mesenchymal transition (EMT), and wound healing. Efforts have been made in recent years to identify novel mediators and targets for this regulation. Connexins form gap junctions and hemichannels, mediating communications between neighboring cells and inside and outside of cells, respectively. Recent evidence suggests that connexins, beyond forming channels, possess channel-independent functions in fibrosis, the EMT, and wound healing. One crucial channel-independent function is their role as the primary functional component for cell adhesion. Other channel-independent functions of connexins involve their roles in mitochondria and exosomes. This review summarizes the latest advances in the channel-dependent and independent roles of connexins in fibrosis, the EMT, and wound healing, with a particular focus on eye diseases, emphasizing their potential as novel, promising therapeutic targets.
    MeSH term(s) Humans ; Connexins/metabolism ; Gap Junctions/metabolism ; Epithelial-Mesenchymal Transition ; Fibrosis ; Membrane Proteins/metabolism ; Wound Healing
    Chemical Substances Connexins ; Membrane Proteins
    Language English
    Publishing date 2023-12-14
    Publishing country Switzerland
    Document type Journal Article ; Review ; Research Support, Non-U.S. Gov't ; Research Support, N.I.H., Extramural
    ZDB-ID 2701262-1
    ISSN 2218-273X ; 2218-273X
    ISSN (online) 2218-273X
    ISSN 2218-273X
    DOI 10.3390/biom13121796
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  4. Article ; Online: Small leucine-rich proteoglycans in physiological and biomechanical function of bone.

    Hua, Rui / Jiang, Jean X

    Matrix biology plus

    2021  Volume 11, Page(s) 100063

    Abstract: Proteoglycans (PGs) contain long unbranched glycosaminoglycan (GAG) chains attached to core proteins. In the bone extracellular matrix, PGs represent a class of non-collagenous proteins, and have high affinity to minerals and collagen. Considering the ... ...

    Abstract Proteoglycans (PGs) contain long unbranched glycosaminoglycan (GAG) chains attached to core proteins. In the bone extracellular matrix, PGs represent a class of non-collagenous proteins, and have high affinity to minerals and collagen. Considering the highly negatively charged character of GAGs and their interfibrillar positioning interconnecting with collagen fibrils, PGs and GAGs play pivotal roles in maintaining hydrostatic and osmotic pressure in the matrix. In this review, we will discuss the role of PGs, especially the small leucine-rich proteoglycans, in regulating the bioactivity of multiple cytokines and growth factors, and the bone turnover process. In addition, we focus on the coupling effects of PGs and GAGs in the hydration status of bone extracellular matrix, thus modulating bone biomechanical properties under physiological and pathological conditions.
    Language English
    Publishing date 2021-05-06
    Publishing country Netherlands
    Document type Journal Article ; Review
    ISSN 2590-0285
    ISSN (online) 2590-0285
    DOI 10.1016/j.mbplus.2021.100063
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article ; Online: Small leucine-rich proteoglycans in physiological and biomechanical function of bone

    Rui Hua / Jean X. Jiang

    Matrix Biology Plus, Vol 11, Iss , Pp 100063- (2021)

    2021  

    Abstract: Proteoglycans (PGs) contain long unbranched glycosaminoglycan (GAG) chains attached to core proteins. In the bone extracellular matrix, PGs represent a class of non-collagenous proteins, and have high affinity to minerals and collagen. Considering the ... ...

    Abstract Proteoglycans (PGs) contain long unbranched glycosaminoglycan (GAG) chains attached to core proteins. In the bone extracellular matrix, PGs represent a class of non-collagenous proteins, and have high affinity to minerals and collagen. Considering the highly negatively charged character of GAGs and their interfibrillar positioning interconnecting with collagen fibrils, PGs and GAGs play pivotal roles in maintaining hydrostatic and osmotic pressure in the matrix. In this review, we will discuss the role of PGs, especially the small leucine-rich proteoglycans, in regulating the bioactivity of multiple cytokines and growth factors, and the bone turnover process. In addition, we focus on the coupling effects of PGs and GAGs in the hydration status of bone extracellular matrix, thus modulating bone biomechanical properties under physiological and pathological conditions.
    Keywords Proteoglycans ; Glycosaminoglycans ; Bound water ; Bone toughness ; Aging ; Biology (General) ; QH301-705.5
    Language English
    Publishing date 2021-08-01T00:00:00Z
    Publisher Elsevier
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  6. Article ; Online: Microinjection of Recombinant RCAS(A) Retrovirus into Embryonic Chicken Lens.

    Acosta, Francisca M / Ma, Bo / Gu, Sumin / Jiang, Jean X

    Journal of visualized experiments : JoVE

    2023  , Issue 199

    Abstract: Embryonic chicken (Gallus domesticus) is a well-established animal model for the study of lens development and physiology, given its high degree of similarity with the human lens. RCAS(A) is a replication-competent chicken retrovirus that infects ... ...

    Abstract Embryonic chicken (Gallus domesticus) is a well-established animal model for the study of lens development and physiology, given its high degree of similarity with the human lens. RCAS(A) is a replication-competent chicken retrovirus that infects dividing cells, which serves as a powerful tool to study the in situ expression and function of wild-type and mutant proteins during lens development by microinjection into the empty lumen of lens vesicle at early developmental stages, restricting its action to surrounding proliferating lens cells. Compared to other approaches, such as transgenic models and ex vivo cultures, the use of an RCAS(A) replication-competent avian retrovirus provides a highly effective, rapid, and customizable system to express exogenous proteins in chick embryos. Specifically, targeted gene transfer can be confined to proliferative lens fiber cells without the need for tissue-specific promoters. In this article, we will briefly overview the steps needed for recombinant retrovirus RCAS(A) preparation, provide a detailed, comprehensive overview of the microinjection procedure, and provide sample results of the technique.
    MeSH term(s) Chick Embryo ; Animals ; Humans ; Chickens ; Microinjections ; Lens, Crystalline ; Lenses ; Retroviridae/genetics
    Language English
    Publishing date 2023-09-01
    Publishing country United States
    Document type Review ; Journal Article ; Video-Audio Media ; Research Support, Non-U.S. Gov't ; Research Support, N.I.H., Extramural
    ZDB-ID 2259946-0
    ISSN 1940-087X ; 1940-087X
    ISSN (online) 1940-087X
    ISSN 1940-087X
    DOI 10.3791/65727
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  7. Article ; Online: Autocrine Factors Produced by Mesenchymal Stem Cells in Response to Cell-Cell Contact Inhibition Have Anti-Tumor Properties.

    Chen, Jerry P / Li, Rong / Jiang, Jean X / Chen, Xiao-Dong

    Cells

    2023  Volume 12, Issue 17

    Abstract: Recently, mesenchymal stem cell (MSC) therapies have been questioned as MSCs are capable of both promoting and inhibiting tumorigenesis. Both MSCs and tumor cells replicate to increase their population size; however, MSCs, but not tumor cells, stop ... ...

    Abstract Recently, mesenchymal stem cell (MSC) therapies have been questioned as MSCs are capable of both promoting and inhibiting tumorigenesis. Both MSCs and tumor cells replicate to increase their population size; however, MSCs, but not tumor cells, stop dividing when they reach confluence due to cell-cell contact inhibition and then differentiate. We hypothesized that contact inhibition results in the production of effector molecules by confluent MSCs and these effectors are capable of suppressing tumor cell growth. To test this hypothesis, we co-cultured breast cancer cells (MDA-MB-231) with either confluent or sub-confluent bone-marrow-derived MSCs (BM-MSCs); in addition, we treated various tumor cells with conditioned media (CM) obtained from either confluent or sub-confluent BM-MSCs. The results showed that the growth of tumor cells co-cultured with confluent BM-MSCs or treated with CM obtained from confluent BM-MSCs was inhibited, and this effect was significantly stronger than that seen with tumor cells co-cultured with sub-confluent BM-MSCs or CM obtained from sub-confluent BM-MSCs. Subcutaneous tumor formation was completely prevented by the inoculation of tumor cells mixed with CM. In the future, soluble anti-tumor effectors, produced by confluent MSCs, may be used as cell-free therapeutics; this approach provides a solution to current concerns associated with cell-based therapies.
    MeSH term(s) Humans ; Contact Inhibition ; Neoplasms ; Carcinogenesis ; Cell Cycle ; Culture Media, Conditioned/pharmacology ; Mesenchymal Stem Cells
    Chemical Substances Culture Media, Conditioned
    Language English
    Publishing date 2023-08-26
    Publishing country Switzerland
    Document type Journal Article ; Research Support, Non-U.S. Gov't ; Research Support, N.I.H., Extramural
    ZDB-ID 2661518-6
    ISSN 2073-4409 ; 2073-4409
    ISSN (online) 2073-4409
    ISSN 2073-4409
    DOI 10.3390/cells12172150
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  8. Article: Connexin 43 Hemichannels Regulate Osteoblast to Osteocyte Differentiation.

    Hua, Rui / Gu, Sumin / Jiang, Jean X

    Frontiers in cell and developmental biology

    2022  Volume 10, Page(s) 892229

    Abstract: Connexin 43 (Cx43) is the predominant connexin subtype expressed in osteocytes. Osteocytes, accounting for 90%-95% of total bone cells, function as orchestrators coordinating balanced activity between bone-resorbing osteoclasts and bone-forming ... ...

    Abstract Connexin 43 (Cx43) is the predominant connexin subtype expressed in osteocytes. Osteocytes, accounting for 90%-95% of total bone cells, function as orchestrators coordinating balanced activity between bone-resorbing osteoclasts and bone-forming osteoblasts. In this study, two newly developed osteocytic cell lines, OCY454 and IDG-SW3, were used to determine the role of Cx43 gap junctions and hemichannels (HCs) in the regulation of osteoblast to osteocyte differentiation. We found that the Cx43 level was substantially increased during the differentiation of IDG-SW3 cells and is also much higher than that of OCY454 cells. We knocked down Cx43 expression using the lentiviral CRISPR/Cas9 approach and inhibition of Cx43 HCs using Cx43 (E2) antibody in IDG-SW3 cells. Cx43 knockdown (KD) or Cx43 HC inhibition decreased gene expression for osteoblast and osteocyte markers, including alkaline phosphatase, type I collagen, dentin matrix protein 1, sclerostin, and fibroblast growth factor 23, whereas increasing the osteoclastogenesis indicator and the receptor activator of nuclear factor kappa-B ligand (RANKL)/osteoprotegerin (OPG) ratio at early and late differentiation stages. Moreover, mineralization was remarkably attenuated in differentiated Cx43-deficient IDG-SW3 cells compared to ROSA26 control. The conditioned medium collected from fully differentiated IDG-SW3 cells with Cx43 KD promoted osteoclastogenesis of RAW264.7 osteoclast precursors. Our results demonstrated that Cx43 HCs play critical roles in osteoblast to osteocyte differentiation process and regulate osteoclast differentiation
    Language English
    Publishing date 2022-05-27
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2737824-X
    ISSN 2296-634X
    ISSN 2296-634X
    DOI 10.3389/fcell.2022.892229
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  9. Article: Connexin 43 hemichannels and prostaglandin E

    Zhao, Dezhi / Wu, Jiawei / Acosta, Francisca M / Xu, Huiyun / Jiang, Jean X

    Frontiers in cell and developmental biology

    2023  Volume 11, Page(s) 1151838

    Abstract: Bone adapts to changes in the physical environment by modulating remodeling through bone resorption and formation to maintain optimal bone mass. As the most abundant connexin subtype in bone tissue, connexin 43 (Cx43)-forming hemichannels are highly ... ...

    Abstract Bone adapts to changes in the physical environment by modulating remodeling through bone resorption and formation to maintain optimal bone mass. As the most abundant connexin subtype in bone tissue, connexin 43 (Cx43)-forming hemichannels are highly responsive to mechanical stimulation by permitting the exchange of small molecules (<1.2 kDa) between bone cells and the extracellular environment. Upon mechanical stimulation, Cx43 hemichannels facilitate the release of prostaglandins E
    Language English
    Publishing date 2023-04-13
    Publishing country Switzerland
    Document type Journal Article ; Review
    ZDB-ID 2737824-X
    ISSN 2296-634X
    ISSN 2296-634X
    DOI 10.3389/fcell.2023.1151838
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  10. Article ; Online: Connexin 43 Hemichannels Regulate Osteoblast to Osteocyte Differentiation

    Rui Hua / Sumin Gu / Jean X. Jiang

    Frontiers in Cell and Developmental Biology, Vol

    2022  Volume 10

    Abstract: Connexin 43 (Cx43) is the predominant connexin subtype expressed in osteocytes. Osteocytes, accounting for 90%–95% of total bone cells, function as orchestrators coordinating balanced activity between bone-resorbing osteoclasts and bone-forming ... ...

    Abstract Connexin 43 (Cx43) is the predominant connexin subtype expressed in osteocytes. Osteocytes, accounting for 90%–95% of total bone cells, function as orchestrators coordinating balanced activity between bone-resorbing osteoclasts and bone-forming osteoblasts. In this study, two newly developed osteocytic cell lines, OCY454 and IDG-SW3, were used to determine the role of Cx43 gap junctions and hemichannels (HCs) in the regulation of osteoblast to osteocyte differentiation. We found that the Cx43 level was substantially increased during the differentiation of IDG-SW3 cells and is also much higher than that of OCY454 cells. We knocked down Cx43 expression using the lentiviral CRISPR/Cas9 approach and inhibition of Cx43 HCs using Cx43 (E2) antibody in IDG-SW3 cells. Cx43 knockdown (KD) or Cx43 HC inhibition decreased gene expression for osteoblast and osteocyte markers, including alkaline phosphatase, type I collagen, dentin matrix protein 1, sclerostin, and fibroblast growth factor 23, whereas increasing the osteoclastogenesis indicator and the receptor activator of nuclear factor kappa-B ligand (RANKL)/osteoprotegerin (OPG) ratio at early and late differentiation stages. Moreover, mineralization was remarkably attenuated in differentiated Cx43-deficient IDG-SW3 cells compared to ROSA26 control. The conditioned medium collected from fully differentiated IDG-SW3 cells with Cx43 KD promoted osteoclastogenesis of RAW264.7 osteoclast precursors. Our results demonstrated that Cx43 HCs play critical roles in osteoblast to osteocyte differentiation process and regulate osteoclast differentiation via secreted factors.
    Keywords IDG-SW3 cells ; Cx43 ; CRISPR/Cas9 ; osteoblast differentiation ; mineralization ; osteoclastogenesis ; Biology (General) ; QH301-705.5
    Subject code 616
    Language English
    Publishing date 2022-05-01T00:00:00Z
    Publisher Frontiers Media S.A.
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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