Browsing by Subject "Integrin"

Now showing 1 - 7 of 7
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    Alcohol exposure decreases osteopontin expression during fracture healing and osteopontin-mediated mesenchymal stem cell migration in vitro
    (BMC, 2018-04-27) Natoli, Roman M.; Yu, Henry; Meislin, Megan Conti-Mica; Abbasnia, Pegah; Roper, Philip; Vuchkovska, Aleksandra; Xiao, Xianghui; Stock, Stuart R.; Callaci, John J.; Orthopaedic Surgery, School of Medicine
    BACKGROUND: Alcohol consumption is a risk factor for impaired fracture healing, though the mechanism(s) by which this occurs are not well understood. Our laboratory has previously shown that episodic alcohol exposure of rodents negatively affects fracture callus development, callus biomechanics, and cellular signaling which regulates stem cell differentiation. Here, we examine whether alcohol alters chemokine expression and/or signaling activity in the mouse fracture callus during early fracture healing. METHODS: A mouse model for alcohol-impaired tibia fracture healing was utilized. Early fracture callus was examined for alcohol-effects on tissue composition, expression of chemokines involved in MSC migration to the fracture site, and biomechanics. The effects of alcohol on MSC migration and cell adhesion receptors were examined in an in vitro system. RESULTS: Mice exposed to alcohol showed decreased evidence of external callus formation, decreased callus-related osteopontin (OPN) expression levels, and decreased biomechanical stiffness. Alcohol exposure decreased rOPN-mediated MSC migration and integrin β1 receptor expression in vitro. CONCLUSIONS: The effects of alcohol exposure demonstrated here on fracture callus-associated OPN expression, rOPN-mediated MSC migration in vitro, and MSC integrin β1 receptor expression in vitro have not been previously reported. Understanding the effects of alcohol exposure on the early stages of fracture repair may allow timely initiation of treatment to mitigate the long-term complications of delayed healing and/or fracture non-union.
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    Cross-Talk between Transforming Growth Factor-β and Periostin Can Be Targeted for Pulmonary Fibrosis
    (American Thoracic Society, 2020-02) Nanri, Yasuhiro; Nunomura, Satoshi; Terasaki, Yasuhiro; Yoshihara, Tomohito; Hirano, Yusuke; Yokosaki, Yasuyuki; Yamaguchi, Yukie; Feghali-Bostwick, Carol; Ajito, Keiichi; Murakami, Shoichi; Conway, Simon J.; Izuhara, Kenji; Pediatrics, School of Medicine
    Idiopathic pulmonary fibrosis (IPF) is a devastating disease characterized as progressive and irreversible fibrosis in the interstitium of lung tissues. There is still an unmet need to develop a novel therapeutic drug for IPF. We have previously demonstrated that periostin, a matricellular protein, plays an important role in the pathogenesis of pulmonary fibrosis. However, the underlying mechanism of how periostin causes pulmonary fibrosis remains unclear. In this study, we sought to learn whether the cross-talk between TGF-β (transforming growth factor-β), a central mediator in pulmonary fibrosis, and periostin in lung fibroblasts leads to generation of pulmonary fibrosis and whether inhibitors for integrin αVβ3, a periostin receptor, can block pulmonary fibrosis in model mice and the TGF-β signals in fibroblasts from patients with IPF. We found that cross-talk exists between TGF-β and periostin signals via αVβ3/β5 converging into Smad3. This cross-talk is necessary for the expression of TGF-β downstream effector molecules important for pulmonary fibrosis. Moreover, we identified several potent integrin low-molecular-weight inhibitors capable of blocking cross-talk with TGF-β signaling. One of the compounds, CP4715, attenuated bleomycin-induced pulmonary fibrosis in vivo in mice and the TGF-β signals in vitro in fibroblasts from patients with IPF. These results suggest that the cross-talk between TGF-β and periostin can be targeted for pulmonary fibrosis and that CP4715 can be a potential therapeutic agent to block this cross-talk.
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    Oncostatin M Improves Cutaneous Wound Re-Epithelialization and Is Deficient under Diabetic Conditions
    (Elsevier, 2022) Das, Amitava; Madeshiya, Amit K.; Biswas, Nirupam; Ghosh, Nandini; Gorain, Mahadeo; Rawat, Atul; Mahajan, Sanskruti P.; Khanna, Savita; Sen, Chandan K.; Roy, Sashwati; Surgery, School of Medicine
    Impaired re-epithelialization characterized by hyperkeratotic non-migratory wound epithelium is a hallmark of non-healing diabetic wounds. In chronic wounds, copious release of oncostatin M (OSM) from wound macrophages is evident. OSM is a potent keratinocyte activator. This work sought to understand the signal transduction pathway responsible for wound-re-epithelialization, the primary mechanism underlying wound closure. Daily topical treatment of full-thickness excisional wounds of C57bl/6 mice with recombinant murine OSM improved wound re-epithelialization and accelerated wound closure by bolstering keratinocyte proliferation and migration. OSM activated the JAK-STAT pathway as manifested by STAT3 phosphorylation. Such signal transduction in the human keratinocyte induced TP63, the master regulator of keratinocyte function. Elevated TP63 induced integrin beta 1, a known effector of keratinocyte migration. In diabetic wounds, OSM was more abundant compared to the level in non-diabetic wounds. However, in diabetic wounds OSM activity was compromised by glycation. Aminoguanidine, a deglycation agent, rescued compromised keratinocyte migration caused by glycated OSM. Finally, topical application of recombinant OSM improved keratinocyte migration and accelerated wound closure in db/db mice. This work recognizes that despite its abundance at the wound-site, OSM is inactivated by glycation and topical delivery of exogenous OSM is likely to be productive in accelerating diabetic wound closure.
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    The Outside-In Journey of Tissue Transglutaminase in Cancer
    (MDPI, 2022-05-29) Sima, Livia Elena; Matei, Daniela; Condello, Salvatore; Obstetrics and Gynecology, School of Medicine
    Tissue transglutaminase (TG2) is a member of the transglutaminase family that catalyzes Ca2+-dependent protein crosslinks and hydrolyzes guanosine 5'-triphosphate (GTP). The conformation and functions of TG2 are regulated by Ca2+ and GTP levels; the TG2 enzymatically active open conformation is modulated by high Ca2+ concentrations, while high intracellular GTP promotes the closed conformation, with inhibition of the TG-ase activity. TG2's unique characteristics and its ubiquitous distribution in the intracellular compartment, coupled with its secretion in the extracellular matrix, contribute to modulate the functions of the protein. Its aberrant expression has been observed in several cancer types where it was linked to metastatic progression, resistance to chemotherapy, stemness, and worse clinical outcomes. The N-terminal domain of TG2 binds to the 42 kDa gelatin-binding domain of fibronectin with high affinity, facilitating the formation of a complex with β-integrins, essential for cellular adhesion to the matrix. This mechanism allows TG2 to interact with key matrix proteins and to regulate epithelial to mesenchymal transition and stemness. Here, we highlight the current knowledge on TG2 involvement in cancer, focusing on its roles translating extracellular cues into activation of oncogenic programs. Improved understanding of these mechanisms could lead to new therapeutic strategies targeting this multi-functional protein.
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    Periostin activates distinct modules of inflammation and itching downstream of the type 2 inflammation pathway
    (Elsevier, 2023) Nunomura, Satoshi; Uta, Daisuke; Kitajima, Isao; Nanri, Yasuhiro; Matsuda, Kosuke; Ejiri, Naoko; Kitajima, Midori; Ikemitsu, Hitoshi; Koga, Misaki; Yamamoto, Sayaka; Honda, Yuko; Takedomi, Hironobu; Andoh, Tsugunobu; Conway, Simon J.; Izuhara, Kenji; Pediatrics, School of Medicine
    Atopic dermatitis (AD) is a chronic relapsing skin disease accompanied by recurrent itching. Although type 2 inflammation is dominant in allergic skin inflammation, it is not fully understood how non-type 2 inflammation co-exists with type 2 inflammation or how type 2 inflammation causes itching. We have recently established the FADS mouse, a mouse model of AD. In FADS mice, either genetic disruption or pharmacological inhibition of periostin, a downstream molecule of type 2 inflammation, inhibits NF-κB activation in keratinocytes, leading to downregulating eczema, epidermal hyperplasia, and infiltration of neutrophils, without regulating the enhanced type 2 inflammation. Moreover, inhibition of periostin blocks spontaneous firing of superficial dorsal horn neurons followed by a decrease in scratching behaviors due to itching. Taken together, periostin links NF-κB-mediated inflammation with type 2 inflammation and promotes itching in allergic skin inflammation, suggesting that periostin is a promising therapeutic target for AD.
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    The Ras-related protein, Rap1A, mediates thrombin-stimulated, integrin-dependent glioblastoma cell proliferation and tumor growth
    (ASBMB, 2014-05-01) Sayyah, Jacqueline; Bartakova, Alena; Nogal, Nekeisha; Quilliam, Lawrence A.; Stupak, Dwayne G.; Brown, Joan Heller; Department of Biochemistry & Molecular Biology, IU School of Medicine
    Rap1 is a Ras family GTPase with a well documented role in ERK/MAP kinase signaling and integrin activation. Stimulation of the G-protein-coupled receptor PAR-1 with thrombin in human 1321N1 glioblastoma cells led to a robust increase in Rap1 activation. This response was sustained for up to 6 h and mediated through RhoA and phospholipase D (PLD). Thrombin treatment also induced a 5-fold increase in cell adhesion to fibronectin, which was blocked by down-regulating PLD or Rap1A or by treatment with a β1 integrin neutralizing antibody. In addition, thrombin treatment led to increases in phospho-focal adhesion kinase (tyrosine 397), ERK1/2 phosphorylation and cell proliferation, which were significantly inhibited in cells treated with β1 integrin antibody or Rap1A siRNA. To assess the role of Rap1A in tumor formation in vivo, we compared growth of 1321N1 cells stably expressing control, Rap1A or Rap1B shRNA in a mouse xenograft model. Deletion of Rap1A, but not of Rap1B, reduced tumor mass by >70% relative to control. Similar observations were made with U373MG glioblastoma cells in which Rap1A was down-regulated. Collectively, these findings implicate a Rap1A/β1 integrin pathway, activated downstream of G-protein-coupled receptor stimulation and RhoA, in glioblastoma cell proliferation. Moreover, our data demonstrate a critical role for Rap1A in glioblastoma tumor growth in vivo.
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    Regulatory role of cholesterol in modulating actin dynamics and cell adhesive interactions in the trabecular meshwork
    (bioRxiv, 2024-02-04) Wang, Ting; Kimmel, Hannah R. C.; Park, Charles; Ryoo, Hyeon; Liu, Jing; Underhill, Gregory H.; Pattabirama, Padmanabhan P.; Ophthalmology, School of Medicine
    The trabecular meshwork (TM) tissue plays a crucial role in maintaining intraocular pressure (IOP) homeostasis. Increased TM contractility and stiffness are directly correlated with elevated IOP. Although cholesterol is known to be a determinant of glaucoma occurrence and elevated IOP, the underlying mechanisms remain elusive. In this study, we used human TM (HTM) cells to unravel the effects of cholesterol on TM stiffness. We achieved this by performing acute cholesterol depletion with Methyl-β-cyclodextrin (MβCD) and cholesterol enrichment/replenishment with MβCD cholesterol complex (CHOL). Interestingly, cholesterol depletion triggered notable actin depolymerization and decreased focal adhesion formation, while enrichment/replenishment promoted actin polymerization, requiring the presence of actin monomers. Using a specific reporter of phosphatidylinositol 4,5-bisphosphate (PIP2), we demonstrated that cholesterol depletion decreases PIP2 levels on the cell membrane, whereas enrichment increases them. Given the critical role of PIP2 in actin remodeling and focal adhesion formation, we postulate that cholesterol regulates actin dynamics by modulating PIP2 levels on the membrane. Furthermore, we showed that cholesterol levels regulate integrin α5β1 and αVβ3 distribution and activation, subsequently altering cell-extracellular matrix (ECM) interactions. Notably, the depletion of cholesterol, as a major lipid constituent of the cell membrane, led to a decrease in HTM cell membrane tension, which was reversed upon cholesterol replenishment. Overall, our systematic exploration of cholesterol modulation on TM stiffness highlights the critical importance of maintaining appropriate membrane and cellular cholesterol levels for achieving IOP homeostasis.