scholarly journals Cardioprotective actions of the sodium-activated potassium channel Slack (aka Slo2.2, KNa1.1 or KCNT1)

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
A Kuret ◽  
R Ehinger ◽  
H Bischof ◽  
A Luczak ◽  
A Bausch ◽  
...  
Keyword(s):  
Potassium Channel ◽  
Research Unit ◽  
In Vivo Model ◽  
Extracellular Potassium ◽  
Funding Source ◽  
Cardiac Damage ◽  
Independent Manner ◽  
And Function

Abstract Background Sodium-activated potassium channels (KNa) Slack (sequence like a calcium-activated potassium channel, aka Slo 2.2, KNa1.1 or KCNT1) are widely expressed throughout neuronal tissue, whereas their presence and function in the cardiovascular system is not well understood. Due to high intracellular sodium concentrations ([Na+]i) necessary to induce half-maximal channel activation, we hypothesized that Slack function is attributed to pathophysiological conditions such as myocardial ischemia. Purpose To elucidate the putative functions of Slack in the murine heart and in cardiomyocytes (CMs) and to explore whether the ischemia and reperfusion (I/R)-induced cardiac damage is affected by endogenous Slack channel activity. Methods I/R injury was evaluated in global and CM-specific Slack knockout mice (Slack gKO, CM Slack KO) and compared to litter-matched controls (Slack gWT, CM Slack CTR) by applying an in vivo model of acute myocardial infarction (MI). Infarct size (IS) was assessed at baseline, after ischemic pre- (iPre) and postconditioning (iPost) and in response to cinaciguat (CIN), a cGMP-elevating agent. Moreover, Slack expression and function in CMs was studied by biochemical and electrophysiological means and by utilizing the newly developed FRET-based K+ probe GEPII 1.0. Results IS in Slack gKO mice was increased in comparison to gWT littermates. In addition, the cardioprotection afforded by iPost was attenuated in the absence of Slack. To test if the increased vulnerability to I/R injury of the Slack gKO mouse model was originating from Slack activity in CMs, we subjected CM-specific Slack CTR and KO mutants to an identical MI procedure. IS measurements confirmed increased cardiac damage at baseline and reduced cardioprotective effects afforded by iPre and iPost in CM Slack KO mice. Interestingly, CIN (i.p., 30 min prior to I/R) reduced IS to a similar extent in both genotypes, suggesting that Slack functions in a cGMP-independent manner. Whole-cell patch clamp experiments on CMs demonstrated a reduction of the KNa-inhibitors clofilium- and chinidine-sensitive K+ outward currents in Slack gKO CM. Extracellular potassium ([K+]ex) accumulation measured with GEPII 1.0 was lower in Slack gKO versus gWT CM pools exposed to membrane permeabilizing agent digitonin. Accordingly, [K+]ex evoked by the Slack activators niclosamide and bithionol was lower in the absence of functional Slack in CMs. Conclusion The presented findings establish an important role of Slack channels for cardioprotective signalling mechanisms during I/R in vivo and for mediating beneficial effects of mechanical conditioning on IS. Corroborating in vitro studies on adult CMs exhibit an impaired [K+]ex dynamic in response to genetic or pharmacological modulation of Slack activity. Thus, we conclude that Slack-dependent K+ signalling pathways in CMs may represent a promising drug target that renders the heart muscle less vulnerable to the I/R-induced damage. Funding Acknowledgement Type of funding source: Public grant(s) – National budget only. Main funding source(s): Work in the authors' laboratories is supported by grants from the Deutsche Forschungsgemeinschaft (DFG) (to R.L.) and the DFG Research Unit 2060, “cGMP Signaling in Cell Growth and Survival” (to R.L. and P.R.).

Cyclic AMP-independent ATF family members interact with NF-kappa B and function in the activation of the E-selectin promoter in response to cytokines

1993 ◽  
Vol 13 (11) ◽  
pp. 7180-7190 ◽  
Author(s):  
W Kaszubska ◽  
R Hooft van Huijsduijnen ◽  
P Ghersa ◽  
A M DeRaemy-Schenk ◽  
B P Chen ◽  
...  
Keyword(s):  
Cyclic Amp ◽  
Consensus Sequence ◽  
Direct Interaction ◽  
Nf Kappa B ◽  
Independent Manner ◽  
Protein Protein Interaction ◽  
Responsive Element ◽  
And Function

We previously reported that NF-kappa B and a complex we referred to as NF-ELAM1 play a central role in cytokine-induced expression of the E-selectin gene. In this study we identify cyclic AMP (cAMP)-independent members of the ATF family binding specifically to the NF-ELAM1 promoter element. The NF-ELAM1 element (TGACATCA) differs by a single nucleotide substitution from the cAMP-responsive element consensus sequence. We demonstrate that this sequence operates in a cAMP-independent manner to induce transcription and thus define it as a non-cAMP-responsive element (NCRE). We show that ATFa is a component of the NF-ELAM1 complex and its overexpression activates the E-selectin promoter. In addition, ATFa, ATF2, and ATF3 interact directly with NF-kappa B in vitro, linking two unrelated families of transcription factors in a novel protein-protein interaction. Furthermore, we demonstrate that the ability of overexpressed NF-kappa B to transactivate the E-selectin promoter in vivo is dependent on the NF-ELAM1 complex. Our results suggest that a direct interaction between ATFs and NF-kappa B is, at least in part, the mechanism by which these factors specifically regulate E-selectin promoter activity.

Preclinical Efficacy of the Investigational Orally Bioavailable Proteasome Inhibitor MLN9708 in Myeloma Bone Disease

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 4014-4014
Author(s):  
Antonio Garcia-Gomez ◽  
Dalia Quwaider ◽  
Enrique M Ocio ◽  
Laura San-Segundo ◽  
Teresa Paíno ◽  
...  
Keyword(s):  
Mouse Model ◽  
Bone Formation ◽  
Proteasome Inhibitor ◽  
Serum Levels ◽  
In Vivo Model ◽  
Healthy Donors ◽  
And Function ◽  
Rpmi 8226

Abstract Abstract 4014 Introduction: Bone destruction, a hallmark of multiple myeloma (MM), arises as a consequence of the interactions between MM cells and the bone marrow microenvironment, which lead to an increase in the bone-resorptive activity and number of osteoclasts (OC) and a reduction of the bone-forming activity and differentiation of osteoblasts (OB). MLN9708, which hydrolyzes to pharmacologically active MLN2238 in aqueous solution, is an investigational proteasome inhibitor (PI) with demonstrated preclinical anti-myeloma activity. However, it is currently not known whether MLN9708, may have a beneficial effect on myeloma-associated bone disease. Here, we have conducted in vitro and in vivo studies to evaluate its ability to promote osteogenic differentiation and to inhibit OC formation and function in the myeloma setting. Patient samples, material and methods: The human MM cell lines RPMI-8226 and MM.1S (or RPMI-8226-luc and MM.1S-luc) together with the mesenchymal stem hMSC-TERT cell line were employed. Also, MSCs from BM samples of healthy donors and MM patients were used in OB differentiation studies, whereas PBMCs from healthy volunteers were used to generate OCs. NOD.SCID.IL2Rγ−/− mice were used in the in vivo model of disseminated human MM. MLN2238 and bortezomib (Velcade) were provided by Millennium Pharmaceuticals, Inc. OB differentiation from MSCs and OB function were investigated by measurement of ALP activity, quantitative mineralization, luciferase reporter assays, siRNA gene silencing and real time RT-PCR. The effect of the new PI on OC formation was assessed by enumeration of multinucleated (≥3) TRAP-positive cells. Measurement of resorbed area, immunofluorescence and flow cytometry were used to further investigate the effect of MLN2238 on OC function. In our in vivo model, bioluminescence imaging, micro-CT analysis and serum levels of Igλ and bone markers were determined. Results: Physiologic concentrations of MLN2238 were able to stimulate the osteogenic differentiation of MSCs from both myeloma patients and healthy donors in vitro to an extent comparable to bortezomib; this was assessed by increased levels of ALP activity, higher expression of bone formation markers (Runx2, osterix, osteopontin and osteocalcin) and augmented matrix mineralization. The enhanced OB formation and function induced by MLN2238 was at least partly due to induction of T-cell factor 4 (TCF4) transcriptional activity, as well as to activation of the unfolded protein response. A similar range of MLN2238 doses also markedly inhibited OC formation and resorption from human progenitors. Similarly to that described with bortezomib, MLN2238 treatment of human pre-OCs prevented RANKL-induced NF-κB activation, disrupted the integrity of the F-actin ring and also reduced the expression of the αVβ3 integrin, thus contributing to inhibition of OC function. MLN2238 was also able to overcome the growth advantage conferred to MM.1S-luc cells by co-culture with MSCs or OCs. Oral administration of MLN2238 in a mouse model of disseminated human MM decreased human RPMI-8226-luc tumor burden as assessed by diminished bioluminescence signal and decreased serum levels of Igλ secreted by RPMI-8226-luc cells. In addition, MLN2238 prevented tumor-associated bone loss with significant increases in femoral trabecular bone parameters as compared to vehicle control animals. Serum markers of bone turnover showed that MLN2238 inhibited bone resorption (decreased levels of CTX) while enhancing bone formation (increased levels of P1NP). Conclusion: MLN2238 in vitro was capable of promoting osteoblastogenesis and OB activity as well as of inhibiting OC formation and function to an extent similar to bortezomib. In a disseminated human MM mouse model, orally administered MLN2238 showed anti-resorptive and bone-anabolic effects in addition to its anti-tumor properties. Given the thus far available data on the preclinical safety and favorable pharmacologic properties of MLN2238, it is conceivable that MLN9708, the clinical formulation of this proteasome inhibitor, may also achieve bone benefits in myeloma patients. Disclosures: Berger: Millennium Pharmaceuticals, Inc.: Employment. San-Miguel:Millennium Pharmaceuticals, Inc.: Consultancy.

scholarly journals Bacterial cell wall-induced hepatic granulomas. An in vivo model of T cell-dependent fibrosis.

1986 ◽  
Vol 163 (4) ◽  
pp. 884-902 ◽  
Author(s):  
S M Wahl ◽  
D A Hunt ◽  
J B Allen ◽  
R L Wilder ◽  
L Paglia ◽  
...  
Keyword(s):  
T Cell ◽  
T Lymphocyte ◽  
Mononuclear Cells ◽  
Specific Antigen ◽  
Physicochemical Analysis ◽  
In Vivo Model ◽  
Fibroblast Growth ◽  
And Function

In vitro studies implicate a molecular link between inflammatory mononuclear cells and alterations in fibroblast growth and function. We have extended these observations in an experimental animal model in which we document the T cell-dependence of fibrosis that occurs after activation of the cell-mediated immune system by specific antigen. Chronic granulomatous lesions were induced in the livers of susceptible rats by the intraperitoneal injection of group A streptococcal cell walls (SCW). The development of granulomas that are composed primarily of lymphocytes and macrophages was associated with the recruitment and proliferation of connective tissue cells. Furthermore, this expanded population of fibroblasts generated a collagenous structure consisting primarily of types I and III collagen around the granuloma. The progression of these chronic inflammatory lesions leads to the formation of fibrotic nodules throughout the livers of the treated animals. Intact granulomas, as well as mononuclear cells derived from the granulomas, spontaneously elaborated a soluble factor(s) that stimulates fibroblast proliferation. Physicochemical analysis revealed that the primary granuloma-derived peak of fibroblast growth activity corresponded to an apparent Mr of 40,000, which is consistent with a previously described T lymphocyte--derived fibroblast-activating factor (FAF) in guinea pig and human. Furthermore, the fibrosis that occurs in the granuloma is apparently T cell--dependent, since no fibrotic lesions developed in SCW-injected athymic nude rats nor in SCW-injected animals treated with the T cell inhibitor, cyclosporin A (CsA). Mononuclear cells from neither of these functionally T cell--deficient animals could generate FAF activity. These data show a role for T lymphocyte--derived cytokines in the development of hepatic fibrosis in SCW-injected rats.

scholarly journals Cyclic AMP-independent ATF family members interact with NF-kappa B and function in the activation of the E-selectin promoter in response to cytokines.

1993 ◽  
Vol 13 (11) ◽  
pp. 7180-7190 ◽  
Author(s):  
W Kaszubska ◽  
R Hooft van Huijsduijnen ◽  
P Ghersa ◽  
A M DeRaemy-Schenk ◽  
B P Chen ◽  
...  
Keyword(s):  
Cyclic Amp ◽  
Consensus Sequence ◽  
Direct Interaction ◽  
Nf Kappa B ◽  
Independent Manner ◽  
Protein Protein Interaction ◽  
Responsive Element ◽  
And Function

We previously reported that NF-kappa B and a complex we referred to as NF-ELAM1 play a central role in cytokine-induced expression of the E-selectin gene. In this study we identify cyclic AMP (cAMP)-independent members of the ATF family binding specifically to the NF-ELAM1 promoter element. The NF-ELAM1 element (TGACATCA) differs by a single nucleotide substitution from the cAMP-responsive element consensus sequence. We demonstrate that this sequence operates in a cAMP-independent manner to induce transcription and thus define it as a non-cAMP-responsive element (NCRE). We show that ATFa is a component of the NF-ELAM1 complex and its overexpression activates the E-selectin promoter. In addition, ATFa, ATF2, and ATF3 interact directly with NF-kappa B in vitro, linking two unrelated families of transcription factors in a novel protein-protein interaction. Furthermore, we demonstrate that the ability of overexpressed NF-kappa B to transactivate the E-selectin promoter in vivo is dependent on the NF-ELAM1 complex. Our results suggest that a direct interaction between ATFs and NF-kappa B is, at least in part, the mechanism by which these factors specifically regulate E-selectin promoter activity.

scholarly journals Cbfa1-independent decrease in osteoblast proliferation, osteopenia, and persistent embryonic eye vascularization in mice deficient in Lrp5, a Wnt coreceptor

2002 ◽  
Vol 157 (2) ◽  
pp. 303-314 ◽  
Author(s):  
Masaki Kato ◽  
Millan S. Patel ◽  
Regis Levasseur ◽  
Ivan Lobov ◽  
Benny H.-J. Chang ◽  
...  
Keyword(s):  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Osteoblast Proliferation ◽  
Targeted Disruption ◽  
Independent Manner ◽  
Wnt Proteins ◽  
Density Lipoprotein Receptor ◽  
And Function

The low-density lipoprotein receptor–related protein (Lrp)-5 functions as a Wnt coreceptor. Here we show that mice with a targeted disruption of Lrp5 develop a low bone mass phenotype. In vivo and in vitro analyses indicate that this phenotype becomes evident postnatally, and demonstrate that it is secondary to decreased osteoblast proliferation and function in a Cbfa1-independent manner. Lrp5 is expressed in osteoblasts and is required for optimal Wnt signaling in osteoblasts. In addition, Lrp5-deficient mice display persistent embryonic eye vascularization due to a failure of macrophage-induced endothelial cell apoptosis. These results implicate Wnt proteins in the postnatal control of vascular regression and bone formation, two functions affected in many diseases. Moreover, these features recapitulate human osteoporosis-pseudoglioma syndrome, caused by LRP5 inactivation.

Tamarix articulata (T. articulata) - An Important Halophytic Medicinal Plant with Potential Pharmacological Properties

2019 ◽  
Vol 20 (4) ◽  
pp. 285-292 ◽  
Author(s):  
Abdullah M. Alnuqaydan ◽  
Bilal Rah
Keyword(s):  
Medicinal Plant ◽  
Biological Activities ◽  
Wide Spectrum ◽  
Biological Properties ◽  
In Vivo Model ◽  
Drug Candidate ◽  
Phytochemical Analysis ◽  
Pharmacological Properties

Background:Tamarix Articulata (T. articulata), commonly known as Tamarisk or Athal in Arabic region, belongs to the Tamaricaece species. It is an important halophytic medicinal plant and a good source of polyphenolic phytochemical(s). In traditional medicines, T. articulata extract is commonly used, either singly or in combination with other plant extracts against different ailments since ancient times.Methods:Electronic database survey via Pubmed, Google Scholar, Researchgate, Scopus and Science Direct were used to review the scientific inputs until October 2018, by searching appropriate keywords. Literature related to pharmacological activities of T. articulata, Tamarix species, phytochemical analysis of T. articulata, biological activities of T. articulata extracts. All of these terms were used to search the scientific literature associated with T. articulata; the dosage of extract, route of administration, extract type, and in-vitro and in-vivo model.Results:Numerous reports revealed that T. articulata contains a wide spectrum of phytochemical(s), which enables it to have a wide window of biological properties. Owing to the presence of high content of phytochemical compounds like polyphenolics and flavonoids, T. articulata is a potential source of antioxidant, anti-inflammatory and antiproliferative properties. In view of these pharmacological properties, T. articulata could be a potential drug candidate to treat various clinical conditions including cancer in the near future.Conclusion:In this review, the spectrum of phytochemical(s) has been summarized for their pharmacological properties and the mechanisms of action, and the possible potential therapeutic applications of this plant against various diseases discussed.

scholarly journals Radiofrequency Irradiation Modulates TRPV1-Related Burning Sensation in Rosacea

Molecules ◽  
2021 ◽  
Vol 26 (5) ◽  
pp. 1424
Author(s):  
Seyeon Oh ◽  
Myeongjoo Son ◽  
Joonhong Park ◽  
Donghwan Kang ◽  
Kyunghee Byun
Keyword(s):  
Burning Sensation ◽  
In Vivo Model ◽  
Molecular Evidence ◽  
Exposed Skin ◽  
Heat Treated ◽  
Vitro Model ◽  
Effective Use ◽  
Inflammatory Molecules

Rosacea is a skin inflammatory condition that is accompanied by not only redness and flushing but also unseen symptoms, such as burning, stinging, and itching. TRPV1 expression in UVB-exposed skin can lead to a painful burning sensation. Upregulated TRPV1 expression helps release neuropeptides, including calcitonin gene-related peptide, pituitary adenylate cyclase-activating polypeptide, and vasoactive intestinal peptide, which can activate macrophage and inflammatory molecules. In this study, we found that radiofrequency (RF) irradiation reduced TRPV1 activation and neuropeptide expression in a UVB-exposed in vivo model and UVB- or heat-treated in an in vitro model. RF irradiation attenuated neuropeptide-induced macrophage activation and inflammatory molecule expression. Interestingly, the burning sensation in the skin of UVB-exposed mice and patients with rosacea was significantly decreased by RF irradiation. These results can provide experimental and molecular evidence on the effective use of RF irradiation for the burning sensation in patients with rosacea.

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