Inhibition of PI3K Prevents the Proliferation and Differentiation of Human Lung Fibroblasts into Myofibroblasts: The Role of Class I P110 Isoforms

Conte, Enrico; Fruciano, Mary; Fagone, Evelina; Gili, Elisa; Caraci, Filippo; Iemmolo, Maria; Crimi, Nunzio; Vancheri, Carlo

doi:10.1371/journal.pone.0024663

Cited by 131 publications

(106 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…S4 and S5). Consistently, Conte et al have shown that LY294002 can also inhibit myofibroblast differentiation of human lung fibroblasts on TCPS (24). The PI3K/AKT pathway is not only necessary for myofibroblast activation on stiff substrates; endogenous AKT activation .…”

Section: Discussionmentioning

confidence: 68%

Hydrogels preserve native phenotypes of valvular fibroblasts through an elasticity-regulated PI3K/AKT pathway

Wang

Tibbitt

Langer

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

142

168

View full text Add to dashboard Cite

Matrix elasticity regulates proliferation, apoptosis, and differentiation of many cell types across various tissues. In particular, stiffened matrix in fibrotic lesions has been shown to promote pathogenic myofibroblast activation. To better understand the underlying pathways by which fibroblasts mechano-sense matrix elasticity, we cultured primary valvular interstitial cells (VICs) isolated from porcine aortic valves on poly(ethylene glycol)-based hydrogels with physiologically relevant and tunable elasticities. We show that soft hydrogels preserve the quiescent fibroblast phenotype of VICs much better than stiff plastic plates. We demonstrate that the PI3K/AKT pathway is significantly upregulated when VICs are cultured on stiff gels or tissue culture polystyrene compared with freshly isolated VICs. In contrast, myofibroblasts de-activate and pAKT/AKT decreases as early as 2 h after reducing the substrate modulus. When PI3K or AKT is inhibited on stiff substrates, myofibroblast activation is blocked. When constitutively active PI3K is overexpressed, the myofibroblast phenotype is promoted even on soft substrates. These data suggest that valvular fibroblasts are sensing the changes in matrix elasticity through the PI3K/AKT pathway. This mechanism may be used by other mechano-sensitive cells in response to substrate modulus, and this pathway may be a worthwhile target for treating matrix stiffness-associated diseases. Furthermore, hydrogels can be designed to recapitulate important mechanical cues in native tissues to preserve aspects of the native phenotype of primary cells for understanding basic cellular responses to biophysical and biochemical signals, and for tissue-engineering applications.mechanosensing | tissue stiffening | phosphatidylinositide 3-kinase signaling E very cell has its distinct microenvironment. Fibroblasts reside in the interstitial mesenchyme, maintaining the balance and structure of the matrix; muscle satellite cells reside between the basal lamina and muscle fibers, waiting to be activated upon injury. In a basic sense, the cellular microenvironment is defined as the extracellular space surrounding and supporting the cell. This microenvironment is often comprised of extracellular matrix (ECM), soluble chemical factors, and neighboring cells. The ECM in particular does not just act as a passive scaffold, but instructs cell fate through the coordinated and dynamic presentation of biochemical and biophysical cues. For example, in fibrotic tissues stiffened by excessive collagen deposition, resident fibroblasts acquire an activated myofibroblast phenotype with α-smooth muscle actin (αSMA) stress fibers (1). The integrity and signaling of the ECM are essential for regulating normal cellular function and maintaining organ homeostasis.The aortic valve, which controls the unidirectional flow of blood during heart contractions, is composed of elastin-, proteoglycanand collagen-rich layers of ECM (2) and supports survival and metabolism of valvular interstitial cells (VICs). VICs are the main fib...

show abstract

Section: Discussionmentioning

confidence: 68%

Hydrogels preserve native phenotypes of valvular fibroblasts through an elasticity-regulated PI3K/AKT pathway

Wang

Tibbitt

Langer

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

142

168

View full text Add to dashboard Cite

show abstract

“…ROS can act as both an upstream and downstream mediator of PDGFR phosphorylation, and the involvement of mitochondrial ROS in PDGFR activation has been reported in cases of autophagy inhibition (22). Furthermore, PI3K/AKT activation (which is downstream of the PDGFR signaling pathway) participates in the regulation of myofibroblast differentiation (23,24). ATG5 knockdown-mediated activation of the PDGFRs/PI3K/AKT signaling pathway was elucidated by the detection of phosphorylated forms of PDGFRs, PI3K, and AKT by Western blotting (Fig.…”

Section: Atg5 Knockdown Induces Mitochondrial Ros Production Activatmentioning

confidence: 99%

Involvement of PARK2-Mediated Mitophagy in Idiopathic Pulmonary Fibrosis Pathogenesis

Kobayashi

Araya

Minagawa

et al. 2016

The Journal of Immunology

113

117

View full text Add to dashboard Cite

Fibroblastic foci, known to be the leading edge of fibrosis development in idiopathic pulmonary fibrosis (IPF), are composed of fibrogenic myofibroblasts. Autophagy has been implicated in the regulation of myofibroblast differentiation. Insufficient mitophagy, the mitochondria-selective autophagy, results in increased reactive oxygen species, which may modulate cell signaling pathways for myofibroblast differentiation. Therefore, we sought to investigate the regulatory role of mitophagy in myofibroblast differentiation as a part of IPF pathogenesis. Lung fibroblasts were used in in vitro experiments. Immunohistochemical evaluation in IPF lung tissues was performed. PARK2 was examined as a target molecule for mitophagy regulation, and a PARK2 knockout mouse was employed in a bleomycin-induced lung fibrosis model. We demonstrated that PARK2 knockdown-mediated mitophagy inhibition was involved in the mechanism for activation of the platelet-derived growth factor receptor (PDGFR)/PI3K/AKT signaling pathway accompanied by enhanced myofibroblast differentiation and proliferation, which were clearly inhibited by treatment with both antioxidants and AG1296, a PDGFR inhibitor. Mitophagy inhibition–mediated activation of PDGFR signaling was responsible for further autophagy suppression, suggesting the existence of a self-amplifying loop of mitophagy inhibition and PDGFR activation. IPF lung demonstrated reduced PARK2 with concomitantly increased PDGFR phosphorylation. Furthermore, bleomycin-induced lung fibrosis was enhanced in PARK2 knockout mice and subsequently inhibited by AG1296. These findings suggest that insufficient mitophagy-mediated PDGFR/PI3K/AKT activation, which is mainly attributed to reduced PARK2 expression, is a potent underlying mechanism for myofibroblast differentiation and proliferation in fibroblastic foci formation during IPF pathogenesis.

show abstract

“…The small interfering RNA (siRNA)-mediated specific knockdown of PI3K (class I) was applied to inhibit the activation of downstream Akt. Scramble siRNA, a non-functional and non-targeting siRNA, was used as the control group [35]. The results showed that TMP significantly suppressed PI3K (class I) and blocked downstream Akt activation.…”

Section: Tmp Completely Reversed the Apoptotic Detrimental Effects Inmentioning

confidence: 99%

Tetramethylpyrazine Ameliorated Hypoxia-Induced Myocardial Cell Apoptosis via HIF-1α/JNK/p38 and IGFBP3/BNIP3 Inhibition to Upregulate PI3K/Akt Survival Signaling

Lin

Kuo²,

Jiang

et al. 2015

Cell Physiol Biochem

View full text Add to dashboard Cite

Background: Hemorrhagic shock (HS) is the major cause of death from trauma. Hemorrhagic shock may lead to cellular hypoxia and organ damage. Our previous findings showed that HS induced a cardiac apoptosis pathway and synergistically caused myocardial cell damage in diabetic rats under trauma-induced HS. Tetramethylpyrazine (TMP) is a major biologically active ingredient purified from the rhizome of Ligusticum wallichii (called Chuang Xiong in Chinese). Chuan Xiong rescued cells from synergistic cardiomyoblast cell injury under high-glucose (HG) conditions plus hypoxia. TMP is one of the most important active ingredients that elevated the survival rate in ischemic brain injury and prevented inducible NO synthase expression to have anti-inflammatory effects against cell damage in different cell types. Method: Here, we further investigate whether TMP can protect against hypoxic (<1% oxygen) conditions in H9c2 cardiomyoblast cells for 24 hrs. Results: Our results showed that hypoxia mediated through HIF-1α/JNK/p38 activation significantly elevated the levels of the hypoxia-related proteins HIF-1α, BNIP3 and IGFBP3, further enhanced the pro-apoptotic protein Bak and upregulated downstream Caspase 9 and 3, resulting in cell death. All of these phenomena were fully recovered under TMP treatment. We observed that TMP exerted this effect by activating the IGF1 receptor survival pathway, dependent primarily on PI3K/Akt. When PI3K (class I) was blocked by specific siRNA, the hypoxia-induced activated caspase 3 and cell apoptosis could not be reversed by TMP treatment. Conclusion: Our results strongly suggest that TMP could be used to restore hypoxia-induced myocardial cell apoptosis and cardiac hypoxic damage.

show abstract

Inhibition of PI3K Prevents the Proliferation and Differentiation of Human Lung Fibroblasts into Myofibroblasts: The Role of Class I P110 Isoforms

Cited by 131 publications

References 24 publications

Hydrogels preserve native phenotypes of valvular fibroblasts through an elasticity-regulated PI3K/AKT pathway

Hydrogels preserve native phenotypes of valvular fibroblasts through an elasticity-regulated PI3K/AKT pathway

Involvement of PARK2-Mediated Mitophagy in Idiopathic Pulmonary Fibrosis Pathogenesis

Tetramethylpyrazine Ameliorated Hypoxia-Induced Myocardial Cell Apoptosis via HIF-1α/JNK/p38 and IGFBP3/BNIP3 Inhibition to Upregulate PI3K/Akt Survival Signaling

Contact Info

Product

Resources

About