scholarly journals Inhibition of cAMP/PKA/CREB Signaling Axis Improves Fibroblast Plasticity for Direct Cardiac Reprogramming

2021 ◽  
Author(s):  
Emre Bektik ◽  
Yu Sun ◽  
Adrienne Dennis ◽  
Phraew Sakon ◽  
Dandan Yang ◽  
...  
Keyword(s):  
Signaling Pathways ◽  
Primary Cell Culture ◽  
Myofibroblast Differentiation ◽  
Camp Concentration ◽  
Cultured Fibroblasts ◽  
Downstream Signaling ◽  
Upstream Regulator ◽  
Reprogramming Efficiency ◽  
Signaling Axis

Direct cardiac reprogramming of fibroblasts into induced cardiomyocytes (iCMs) is a promising approach but remains a challenging technology of regenerative medicine for damaged myocardium. Efforts have been focused on improving the efficiency by understanding fundamental mechanisms. One of the major challenges is that the plasticity of cultured fibroblast varies batch to batch with unknown mechanisms. Here, we noticed that a portion of in vitro cultured fibroblasts have been activated to differentiate into myofibroblasts, marked by the expression of αSMA, even in the primary cell culture of tissues. Both forskolin, which activates adenylyl cyclase and increases cAMP concentration, and TGFbeta inhibitor SB431542 can efficiently suppress myofibroblast differentiation of cultured fibroblasts. However, SB431542 improved but forskolin blocked iCM reprogramming of fibroblasts that were infected with retroviruses of Gata4, Mef2c and Tbx5 (GMT). Moreover, inhibitors of cAMP downstream signaling pathways, PKA or CREB-CBP, significantly improved the efficiency of iCM reprogramming. Consistently, inhibition of p38/MAPK, another upstream regulator of CREB-CBP, also improved reprogramming efficiency. We then investigated if inhibition of these signaling pathways in primary cultured fibroblast could improve their plasticity for reprogramming, and found that preconditioning of cultured fibroblasts with CREB-CBP inhibitor significantly improved the cellular plasticity of fibroblasts to be reprogrammed, yielding ~2-fold amount of reprogrammed iCMs compared to that of untreated control cells. In conclusion, suppression of cAMP/PKA/CREB signaling axis improves fibroblast plasticity for direct cardiac reprogramming.

scholarly journals Inhibition of CREB-CBP Signaling Improves Fibroblast Plasticity for Direct Cardiac Reprogramming

Cells ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1572
Author(s):  
Emre Bektik ◽  
Yu Sun ◽  
Adrienne T. Dennis ◽  
Phraew Sakon ◽  
Dandan Yang ◽  
...  
Keyword(s):  
Signaling Pathways ◽  
Cell Cultures ◽  
Myofibroblast Differentiation ◽  
Heart Regeneration ◽  
Cultured Fibroblasts ◽  
Downstream Signaling ◽  
Upstream Regulator ◽  
Reprogramming Efficiency ◽  
Camp Levels

Direct cardiac reprogramming of fibroblasts into induced cardiomyocytes (iCMs) is a promising approach but remains a challenge in heart regeneration. Efforts have focused on improving the efficiency by understanding fundamental mechanisms. One major challenge is that the plasticity of cultured fibroblast varies batch to batch with unknown mechanisms. Here, we noticed a portion of in vitro cultured fibroblasts have been activated to differentiate into myofibroblasts, marked by the expression of αSMA, even in primary cell cultures. Both forskolin, which increases cAMP levels, and TGFβ inhibitor SB431542 can efficiently suppress myofibroblast differentiation of cultured fibroblasts. However, SB431542 improved but forskolin blocked iCM reprogramming of fibroblasts that were infected with retroviruses of Gata4, Mef2c, and Tbx5 (GMT). Moreover, inhibitors of cAMP downstream signaling pathways, PKA or CREB-CBP, significantly improved the efficiency of reprogramming. Consistently, inhibition of p38/MAPK, another upstream regulator of CREB-CBP, also improved reprogramming efficiency. We then investigated if inhibition of these signaling pathways in primary cultured fibroblasts could improve their plasticity for reprogramming and found that preconditioning of cultured fibroblasts with CREB-CBP inhibitor significantly improved the cellular plasticity of fibroblasts to be reprogrammed, yielding ~2-fold more iCMs than untreated control cells. In conclusion, suppression of CREB-CBP signaling improves fibroblast plasticity for direct cardiac reprogramming.

scholarly journals Receptor Tyrosine Kinases and Their Signaling Pathways as Therapeutic Targets of Curcumin in Cancer

2021 ◽  
Vol 12 ◽  
Author(s):  
Sareshma Sudhesh Dev ◽  
Syafiq Asnawi Zainal Abidin ◽  
Reyhaneh Farghadani ◽  
Iekhsan Othman ◽  
Rakesh Naidu
Keyword(s):  
Signaling Pathways ◽  
Cancer Progression ◽  
Tyrosine Kinases ◽  
Receptor Tyrosine Kinases ◽  
Surface Proteins ◽  
Downstream Signaling ◽  
Anti Cancer ◽  
Rtk Inhibitors

Receptor tyrosine kinases (RTKs) are transmembrane cell-surface proteins that act as signal transducers. They regulate essential cellular processes like proliferation, apoptosis, differentiation and metabolism. RTK alteration occurs in a broad spectrum of cancers, emphasising its crucial role in cancer progression and as a suitable therapeutic target. The use of small molecule RTK inhibitors however, has been crippled by the emergence of resistance, highlighting the need for a pleiotropic anti-cancer agent that can replace or be used in combination with existing pharmacological agents to enhance treatment efficacy. Curcumin is an attractive therapeutic agent mainly due to its potent anti-cancer effects, extensive range of targets and minimal toxicity. Out of the numerous documented targets of curcumin, RTKs appear to be one of the main nodes of curcumin-mediated inhibition. Many studies have found that curcumin influences RTK activation and their downstream signaling pathways resulting in increased apoptosis, decreased proliferation and decreased migration in cancer both in vitro and in vivo. This review focused on how curcumin exhibits anti-cancer effects through inhibition of RTKs and downstream signaling pathways like the MAPK, PI3K/Akt, JAK/STAT, and NF-κB pathways. Combination studies of curcumin and RTK inhibitors were also analysed with emphasis on their common molecular targets.

scholarly journals Pharmacological Modulation of Ubiquitin-Proteasome Pathways in Oncogenic Signaling

2021 ◽  
Vol 22 (21) ◽  
pp. 11971
Author(s):  
Anmol Sharma ◽  
Heena Khan ◽  
Thakur Gurjeet Singh ◽  
Amarjot Kaur Grewal ◽  
Agnieszka Najda ◽  
...  
Keyword(s):  
Signaling Pathways ◽  
Cell Cycle Control ◽  
In Vivo Studies ◽  
Oncogenic Signaling ◽  
Aberrant Expression ◽  
Downstream Signaling ◽  
Ubiquitin Proteasome ◽  
Progressive Growth

The ubiquitin-proteasome pathway (UPP) is involved in regulating several biological functions, including cell cycle control, apoptosis, DNA damage response, and apoptosis. It is widely known for its role in degrading abnormal protein substrates and maintaining physiological body functions via ubiquitinating enzymes (E1, E2, E3) and the proteasome. Therefore, aberrant expression in these enzymes results in an altered biological process, including transduction signaling for cell death and survival, resulting in cancer. In this review, an overview of profuse enzymes involved as a pro-oncogenic or progressive growth factor in tumors with their downstream signaling pathways has been discussed. A systematic literature review of PubMed, Medline, Bentham, Scopus, and EMBASE (Elsevier) databases was carried out to understand the nature of the extensive work done on modulation of ubiquitin-proteasome pathways in oncogenic signaling. Various in vitro, in vivo studies demonstrating the involvement of ubiquitin-proteasome systems in varied types of cancers and the downstream signaling pathways involved are also discussed in the current review. Several inhibitors of E1, E2, E3, deubiquitinase enzymes and proteasome have been applied for treating cancer. Some of these drugs have exhibited successful outcomes in in vivo studies on different cancer types, so clinical trials are going on for these inhibitors. This review mainly focuses on certain ubiquitin-proteasome enzymes involved in developing cancers and certain enzymes that can be targeted to treat cancer.

scholarly journals EV20/NMS-P945, a Novel Thienoindole Based Antibody-Drug Conjugate Targeting HER-3 for Solid Tumors

Pharmaceutics ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 483
Author(s):  
Emily Capone ◽  
Rossano Lattanzio ◽  
Fabio Gasparri ◽  
Paolo Orsini ◽  
Cosmo Rossi ◽  
...  
Keyword(s):  
Critical Role ◽  
Ovarian Cancer Cells ◽  
Antibody Drug Conjugate ◽  
Dna Minor Groove ◽  
Drug Conjugate ◽  
Downstream Signaling ◽  
Toxicological Studies ◽  
Signaling Axis ◽  
Antibody Drug

HER-3 is becoming an attractive target for antibody–drug conjugate (ADC)-based therapy. Indeed, this receptor and its ligands are found to be overexpressed in several malignancies, and re-activation of its downstream signaling axis is known to play a critical role in modulating the sensitivity of targeted therapeutics in different tumors. In this study, we generated a novel ADC named EV20/NMS-P945 by coupling the anti-HER-3 antibody EV20 with a duocarmycin-like derivative, the thienoindole (TEI) NMS-P528, a DNA minor groove alkylating agent through a peptidic cleavable linker. This ADC showed target-dependent cytotoxic activity in vitro on several tumor cell lines and therapeutic activity in mouse xenograft tumor models, including those originating from pancreatic, prostatic, head and neck, gastric and ovarian cancer cells and melanoma. Pharmacokinetics and toxicological studies in monkeys demonstrated that this ADC possesses a favorable terminal half-life and stability and it is well tolerated. These data support further EV20/NMS-P945 clinical development as a therapeutic agent against HER-3-expressing malignancies.

scholarly journals Warfarin Treatment Alters Gas6 and Protein S Activity and Their Downstream Signaling Pathways in Brain, and Stimulates Microglial Activity (P24-002-19)

2019 ◽  
Vol 3 (Supplement_1) ◽  
Author(s):  
Guylaine Ferland ◽  
Pierre Allaire ◽  
Bouchra Ouliass
Keyword(s):  
Signaling Pathways ◽  
Tyrosine Kinases ◽  
Protein S ◽  
Convincing Evidence ◽  
Bdnf Expression ◽  
Behavioral Impairment ◽  
Downstream Signaling ◽  
Funding Sources ◽  
Male Wistar Rats

Abstract Objectives There is now convincing evidence that vitamin K (VK) has important actions in the nervous system and cognition. Two VK-dependent proteins are closely linked to the brain namely Gas6 and protein S (PS). Functionally, both proteins are ligands for receptors of tyrosine kinases Tyro3, Axl, and Mer. In vitro, Gas6 and PS have been shown to possess pro-survival activity towards neurons and glia through stimulation of the extracellular signal-regulated (ERK) and serine-threonine (Akt) kinases pathways. In a previous study, targeted depletion of VK in brain induced by warfarin (W) treatment, a VK antagonist, resulted in cognitive and behavioral impairment. In the present study, we aimed to characterize the role of Gas6 and PS and their signaling pathways in W-treated rats fed or not with supplemental menaquinone-4 (MK-4), the principal K vitamer in brain. Methods Male Wistar rats (n = 5–7/gp) were randomly allocated to a AIN-93 based diet containing 750 mcg phylloquinone (K1)/kg/d supplemented with 100 mg MK-4/kg/d (MK-4) or not (N). After one week, rats were administered 14 mg W/kg/d (in drinking water) and subcutaneous K1 (94 mg/kg), 3X/wk, for 9 wks. [Subcutaneous K1 treatment is required to maintain the coagulation function]. A control gp (C) treated with normal water and injected with saline was also included. Gas6, PS, pAkt, pERK as well as brain-derived neurotrophic factor (BDNF) and microglial CD11b/c protein, were assessed in hippocampus (HPP), frontal cortex (FC) and striatum (STR), three regions involved in cognition, by immunoblotting. Group difference were tested by one-way ANOVA. Results Impact of W treatment was particularly marked in HPP, rats from N group showing decreased Gas6, PS and ERK activity as well as decreased BDNF expression, compared to C gp. Further, rats from N group presented increased expression of CD11bc, a marker of inflammation (all P < 0.05). Supplementing the diet with MK-4 normalized PS activity and BDNF and CD11bc expression in HPP, Gas6 and pERK in CF, and pAkt in STR (all P < 0.05). Conclusions Results indicate that W treatment as used in the present study alters Gas6 and PS activity and their downstream signaling pathways, and stimulates microglial activity. Supplementing the diet with large amounts of MK-4 normalized much of the phenotype. Funding Sources Study funded by CIHR.

scholarly journals CD14 dependence of TLR4 endocytosis and TRIF signaling displays ligand specificity and is dissociable in endotoxin tolerance

2015 ◽  
Vol 112 (27) ◽  
pp. 8391-8396 ◽  
Author(s):  
Rajesh Rajaiah ◽  
Darren J. Perkins ◽  
Derek D. C. Ireland ◽  
Stefanie N. Vogel
Keyword(s):  
Signaling Pathways ◽  
Lipid A ◽  
Endotoxin Tolerance ◽  
Murine Macrophages ◽  
Receptor Endocytosis ◽  
Downstream Signaling ◽  
Tnf Α ◽  
Signaling Axis ◽  
Myeloid Differentiation Factor ◽  
Cluster Of Differentiation

Dimerization of Toll-like receptor 4 (TLR4)/myeloid differentiation factor 2 (MD2) heterodimers is critical for both MyD88- and TIR-domain–containing adapter-inducing IFN-β (TRIF)-mediated signaling pathways. Recently, Zanoni et al. [(2011)Cell147(4):868–880] reported that cluster of differentiation 14 (CD14) is required for LPS-/Escherichia coli- induced TLR4 internalization into endosomes and activation of TRIF-mediated signaling in macrophages. We confirmed their findings with LPS but report here that CD14 is not required for receptor endocytosis and downstream signaling mediated by TLR4/MD2 agonistic antibody (UT12) and synthetic small-molecule TLR4 ligands (1Z105) in murine macrophages. CD14 deficiency completely ablated the LPS-induced TBK1/IRF3 signaling axis that mediates production of IFN-β in murine macrophages without affecting MyD88-mediated signaling, including NF-κB, MAPK activation, and TNF-α and IL-6 production. However, neither the MyD88- nor TRIF-signaling pathways and their associated cytokine profiles were altered in the absence of CD14 in UT12- or 1Z105-treated murine macrophages. Eritoran (E5564), a lipid A antagonist that binds the MD2 “pocket,” completely blocked LPS- and 1Z105-driven, but not UT12-induced, TLR4 dimerization and endocytosis. Furthermore, TLR4 endocytosis is induced in macrophages tolerized by exposure to either LPS or UT12 and is independent of CD14. These data indicate that TLR4 receptor endocytosis and the TRIF-signaling pathway are dissociable and that TLR4 internalization in macrophages can be induced by UT12, 1Z105, and during endotoxin tolerance in the absence of CD14.

The Bcr-Abl SH2-Kinase Domain Interface Is Critical for Leukemogenesis and An Additional Therapeutic Target in CML.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 37-37
Author(s):  
Oliver D. Hantschel ◽  
Florian Grebien ◽  
Ines Kaupe ◽  
Boris Kovacic ◽  
John Wojcik ◽  
...  
Keyword(s):  
Tyrosine Kinase ◽  
Signaling Pathways ◽  
Kinase Activity ◽  
Critical Factor ◽  
Kinase Domain ◽  
Sh2 Domain ◽  
Wild Type ◽  
Tyrosine Kinase Activity ◽  
Downstream Signaling

Abstract Abstract 37 We previously showed that the Abl SH2 domain is an allosteric activator of c-Abl tyrosine kinase activity and substrate phosphorylation (Filippakopoulos et al. (2008) Cell 134(5), 793-803). This effect is exerted directly by docking of the SH2 domain onto the N-lobe of the kinase domain in the active conformation of c-Abl. We also showed that the same structural mechanism is a critical factor for full activation of the oncogenic fusion kinase Bcr-Abl. Disruption of binding of the SH2 domain to the kinase domain in Bcr-Abl by the Ile164Glu mutation in the SH2 domain, led to a strong reduction in in vitro tyrosine kinase activity and Bcr-Abl autophosphorylation. Unexpectedly, we observed a differential attenuation of downstream signaling pathways upon disruption of the SH2-kinase domain interface, indicating different activation thresholds of Bcr-Abl downstream signaling pathways. Here, we show that disrupting the SH2-kinase domain interface abrogates the transforming capacity of Bcr-Abl. Cells expressing the Bcr-Abl Ile164Glu mutant were unable to generate cytokine-independent colonies in vitro. Furthermore, mice transplanted with Bcr-Abl Ile164Glu expressing bone marrow cells did not develop the characteristic MPD-like disease that is caused by wild-type Bcr-Abl. Mice that received Bcr-Abl Ile164Glu cells showed normal survival, blood counts and histology after more than 100 days post-transplant, despite the presence of Bcr-Abl Ile164Glu-expressing cells in all blood lineages. This shows that the formation of the SH2-kinase domain interface is strictly necessary for Bcr-Abl to cause CML. Together with our data that show sensitization to imatinib inhibition of Bcr-Abl Ile164Glu as compared to Bcr-Abl wild-type, this argues for the SH2-kinase domain interface as an additional drug target on Bcr-Abl that may synergize with tyrosine kinase inhibitors and may be useful to inhibit tyrosine kinase inhibitor resistant Bcr-Abl clones. To address possibilities to interfere with the SH2-kinase domain interface, we are using an engineered binding protein that binds to the Abl SH2 domain with high-affinity and specificity and supposedly disrupts the interface with the kinase domain, resulting in a decrease in Bcr-Abl kinase activity. In conclusion, we provide strong evidence that the structural positioning of the SH2 domain is a crucial factor for constitutive activity, signal transduction and leukemogenicity of Bcr-Abl. Besides oligomerization via the N-terminal coiled-coiled domain and loss of the auto-inhibitory N-terminal myristoyl group, the proper positioning of the SH2 domain appears to be another critical factor that is required for constitutive activation of Bcr-Abl. Inhibitors of the SH2-kinase domain interface of Bcr-Abl may comprise alternative or additional points of pharmacological intervention for the treatment of imatinib-sensitive or -resistant CML or Ph+ acute lymphocytic leukemia. Disclosures: No relevant conflicts of interest to declare.

scholarly journals TC21 causes transformation by Raf-independent signaling pathways.

1996 ◽  
Vol 16 (11) ◽  
pp. 6132-6140 ◽  
Author(s):  
S M Graham ◽  
A B Vojtek ◽  
S Y Huff ◽  
A D Cox ◽  
G J Clark ◽  
...  
Keyword(s):  
Cell Growth ◽  
Signaling Pathways ◽  
Amino Acid Identity ◽  
Nucleotide Exchange ◽  
Wild Type ◽  
Downstream Signaling ◽  
Transforming Activity ◽  
Cell Growth And Differentiation

Although the Ras-related protein TC21/R-Ras2 has only 55% amino acid identity with Ras proteins, mutated forms of TC21 exhibit the same potent transforming activity as constitutively activated forms of Ras. Therefore, like Ras, TC21 may activate signaling pathways that control normal cell growth and differentiation. To address this possibility, we determined if regulators and effectors of Ras are also important for controlling TC21 activity. First, we determined that Ras guanine nucleotide exchange factors (SOS1 and RasGRF/CDC25) synergistically enhanced wild-type TC21 activity in vivo and that Ras GTPase-activating proteins (GAPs; p120-GAP and NF1-GAP) stimulated wild-type TC21 GTP hydrolysis in vitro. Thus, extracellular signals that activate Ras via SOS1 activation may cause coordinate activation of Ras and TC21. Second, we determined if Raf kinases were effectors for TC21 transformation. Unexpectedly, yeast two-hybrid binding analyses showed that although both Ras and TC21 could interact with the isolated Ras-binding domain of Raf-1, only Ras interacted with full-length Raf-1, A-Raf, or B-Raf. Consistent with this observation, we found that Ras- but not TC21-transformed NIH 3T3 cells possessed constitutively elevated Raf-1 and B-Raf kinase activity. Thus, Raf kinases are effectors for Ras, but not TC21, signaling and transformation. We conclude that common upstream signals cause activation of Ras and TC21, but activated TC21 controls cell growth via distinct Raf-independent downstream signaling pathways.

scholarly journals Signaling Pathways in Proton and Non-proton ASIC1a Activation

2021 ◽  
Vol 15 ◽  
Author(s):  
Libia Catalina Salinas Castellanos ◽  
Osvaldo Daniel Uchitel ◽  
Carina Weissmann
Keyword(s):  
Signaling Pathways ◽  
Sodium Influx ◽  
Downstream Signaling ◽  
Pathological Conditions ◽  
Acid Sensing Ion Channels ◽  
Sustained Effect ◽  
Pathological Mechanism ◽  
Large Extracellular Loop ◽  
Downstream Signaling Pathway

Acid-sensing ion channels (ASICs) regulate synaptic activities and play important roles in neurodegenerative diseases as well as pain conditions. Classically, ASICs are described as transiently activated by a reduced pH, followed by desensitization; the activation allows sodium influx, and in the case of ASIC1a-composed channels, also calcium to some degree. Several factors are emerging and extensively analyzed as modulators, activating, inhibiting, and potentiating specific channel subunits. However, the signaling pathways triggered by channel activation are only starting to be revealed.The channel has been recently shown to be activated through a mechanism other than proton-mediated. Indeed, the large extracellular loop of these channels opens the possibility that other non-proton ligands might exist. One such molecule discovered was a toxin present in the Texas coral snake venom. The finding was associated with the activation of the channel at neutral pH via the toxin and causing intense and unremitting pain.By using different pharmacological tools, we analyzed the downstream signaling pathway triggered either by the proton and non-proton activation for human, mouse, and rat ASIC1a-composed channels in in vitro models. We show that for all species analyzed, the non-protonic mode of activation determines the activation of the ERK signaling cascade at a higher level and duration compared to the proton mode.This study adds to the growing evidence of the important role ASIC1a channels play in different physiological and pathological conditions and also hints at a possible pathological mechanism for a sustained effect.

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