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1.
J Gen Intern Med ; 2024 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-38886322

RESUMO

BACKGROUND: Community health centers grapple with high no-show rates, posing challenges to patient access and primary care provider (PCP) utilization. AIM: To address these challenges, we implemented a virtual waiting room (VWR) program in April 2023 to enhance patient access and boost PCP utilization. SETTING: Academic community health center in a small urban city in Massachusetts. PARTICIPANTS: Community health patients (n = 8706) and PCP (n = 14). PROGRAM DESCRIPTION: The VWR program, initiated in April 2023, involved nurse triage of same-day visit requests for telehealth appropriateness, then placing patients in a standby pool to fill in as a telehealth visit for no-shows or last-minute cancellations in PCP schedules. PROGRAM EVALUATION: Post-implementation, clinic utilization rates between July and September improved from 75.2% in 2022 to 81.2% in 2023 (p < 0.01). PCP feedback was universally positive. Patients experienced a mean wait time of 1.9 h, offering a timely and convenient alternative to urgent care or the ER. DISCUSSION: The VWR is aligned with the quadruple aim of improving patient experience, population health, cost-effectiveness, and PCP satisfaction through improving same-day access and improving PCP schedule utilization. This innovative and reproducible approach in outpatient offices utilizing telehealth holds the potential for enhancing timely access across various medical disciplines.

2.
J Thorac Oncol ; 18(6): 744-754, 2023 06.
Artigo em Inglês | MEDLINE | ID: mdl-36738930

RESUMO

INTRODUCTION: EGFR exon 20 insertion (ex20ins) mutations represent 5% to 10% of EGFR mutations in NSCLC. Identifying patients with EGFR ex20ins is challenging owing to the limited coverage of polymerase chain reaction (PCR) assays and the relatively recent use of next-generation sequencing (NGS). This study analyzes the spectrum of EGFR ex20ins variants in a large patient population from a global clinical trial and several real-world cohorts and the ability of PCR kits to identify these alterations. METHODS: We conducted this retrospective analysis in patients with NSCLC who underwent NGS or other sequencing testing and had a known EGFR ex20ins mutation. Patients were gathered from a clinical trial (NCT02716116), a chart review study in Germany, and the LC-SCRUM-Japan, GENIE, and U.S. COTA databases. Proportions of patients with ex20ins variants that could have been detected by six commercially available and widely used PCR kits were calculated in each data set. RESULTS: Overall, 636 patients with NSCLC harboring EGFR ex20ins mutations were included in this analysis and 104 unique EGFR ex20ins variants were identified across the data sources. The proportion of patients whose ex20ins could have been detected by any PCR test alone ranged from 11.8% to 58.9% across the data sources. CONCLUSIONS: Our findings suggest that the PCR tests evaluated would have missed more than 40% of patients with NSCLC harboring EGFR ex20ins mutations. NGS-based genetic testing is preferable than standard PCR assays and can substantially improve the identification of the diverse profile of EGFR ex20ins variants in NSCLC.


Assuntos
Carcinoma Pulmonar de Células não Pequenas , Neoplasias Pulmonares , Humanos , Neoplasias Pulmonares/genética , Estudos Retrospectivos , Receptores ErbB/genética , Carcinoma Pulmonar de Células não Pequenas/genética , Mutação , Éxons/genética , Inibidores de Proteínas Quinases
3.
Expert Rev Anticancer Ther ; 23(1): 95-106, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36537204

RESUMO

BACKGROUND: Mobocertinib has demonstrated durable clinical benefit in platinum-pretreated patients (PPP) with epidermal growth factor receptor exon 20 insertion-positive non-small cell lung cancer (NSCLC). RESEARCH DESIGN AND METHODS: Pooled safety analysis of two studies included patients with NSCLC (N = 257) treated with the recommended phase 2 dose (RP2D) of mobocertinib (160 mg once daily). We report overall safety (treatment-emergent adverse events [TEAEs]) in the RP2D population; characterization of GI and skin-related events in 114 PPP from a phase 1/2 study (NCT02716116); and clinical activity in PPP with and without dose reductions due to TEAEs. RESULTS: In the RP2D population (N = 257), the most common TEAEs were diarrhea (93%), nausea (47%), rash (38%), and vomiting (37%). In PPP (N = 114), median times to diarrhea onset and resolution were 5 and 2 days, respectively. Median times to onset and resolution of skin-related events were 9 and 78 days, respectively. Among PPP with (n = 29) or without (n = 85) dose reductions due to TEAEs, overall response rates were 21% and 31% and median durations of response were 5.7 and 17.5 months, respectively. CONCLUSIONS: GI and skin-related events are common with mobocertinib; minimizing dose reductions with proactive management may improve clinical outcomes. TRIAL REGISTRATION: NCT02716116; NCT03807778.


Mobocertinib is a treatment for patients with a certain type of lung cancer. We analyzed the safety of mobocertinib in 257 patients with lung cancer. The most common side effects with mobocertinib were diarrhea, nausea, vomiting, and skin rash. In 114 patients with lung cancer who were treated in the past with chemotherapy that included platinum-based drugs, diarrhea started after about 5 days of mobocertinib treatment and went away in about 2 days. Skin-related side effects started after about 9 days and went away in about 2.5 months. One-fifth of patients who had to receive a smaller amount of mobocertinib because of side effects responded to treatment compared with one-third of patients who received the recommended mobocertinib amount. Managing side effects quickly can better help patients with lung cancer who are treated with mobocertinib.


Assuntos
Carcinoma Pulmonar de Células não Pequenas , Neoplasias Pulmonares , Humanos , Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Neoplasias Pulmonares/tratamento farmacológico , Receptores ErbB/genética , Mutação , Diarreia/induzido quimicamente , Inibidores de Proteínas Quinases
4.
Curr Med Res Opin ; 38(8): 1341-1350, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-35621011

RESUMO

INTRODUCTION: EGFR exon 20 insertion mutation-positive non-small cell lung cancer (NSCLC) is rare, has a poor prognosis, and outcomes are not fully established. We describe and evaluate outcomes from real-world and clinical evidence in these patients. METHODS: A systematic literature review (SLR) identified interventional and real-world evidence (RWE) studies reporting clinical outcomes for EGFR exon 20 insertion mutation-positive NSCLC. Meta-analyses were conducted by line of therapy to synthesize pooled survival and response outcomes across RWE. Published evidence from interventional studies was summarized individually. RESULTS: The SLR identified 23 RWE and 19 original interventional studies. In the meta-analysis of RWE, pooled response and survival outcomes were low for first-line EGFR-tyrosine kinase inhibitors (TKIs) and immuno-oncology (IO) agents. First-line chemotherapy resulted in a pooled ORR 25.7%, pooled PFS 5.6 months, and pooled OS 18.3 months. Pooled outcomes were further reduced in second or later lines (≥2 L): pooled ORR was 5.0%, 3.3%, and 13.9%; pooled PFS was 2.1 months, 2.3 months, and 4.4 months; and pooled OS was 14.1 months, 8.8 months, and 17.1 months (not a pooled result) for EGFR-TKIs, IO agents, and chemotherapy, respectively. Interventional studies reported outcomes for TKIs (mobocertinib, poziotinib, osimertinib, afatinib, CLN-081, DZD9008), a monoclonal antibody (amivantamab), and a heat shock protein 90 inhibitor (luminespib). While there is limited RWE for the recently approved agents mobocertinib and amivantamab, which specifically target exon 20 insertion mutations, interventional evidence supports their potential as effective treatment options. CONCLUSIONS: Conventional treatments used in patients with EGFR exon 20 insertion mutation-positive NSCLC have limited efficacy, though chemotherapy appeared to be associated with better response and survival outcomes than non-exon 20 targeting EGFR-TKIs and IO agents. This supports the need to identify EGFR exon 20 insertion mutations as the availability of new targeted treatments may offer additional therapeutic options to these patients.


Assuntos
Carcinoma Pulmonar de Células não Pequenas , Receptores ErbB , Neoplasias Pulmonares , Anticorpos Biespecíficos , Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Carcinoma Pulmonar de Células não Pequenas/genética , Receptores ErbB/genética , Humanos , Neoplasias Pulmonares/tratamento farmacológico , Neoplasias Pulmonares/genética , Mutagênese Insercional , Mutação , Inibidores de Proteínas Quinases/uso terapêutico
5.
J Mol Cell Cardiol ; 51(6): 980-7, 2011 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-21920368

RESUMO

We previously found that in the hearts of hypertensive Dahl salt-sensitive rats, ßIIPKC levels increase during the transition from compensated cardiac hypertrophy to cardiac dysfunction. Here we showed that a six-week treatment of these hypertensive rats with a ßIIPKC-specific inhibitor, ßIIV5-3, prolonged their survival by at least 6weeks, suppressed myocardial fibrosis and inflammation, and delayed the transition from compensated hypertrophy to cardiac dysfunction. In addition, changes in the levels of the Ca(2+)-handling proteins, SERCA2 and the Na(+)/Ca(2+) exchanger, as well as troponin I phosphorylation, seen in the control-treated hypertensive rats were not observed in the ßΙΙPKC-treated rats, suggesting that ßΙΙPKC contributes to the regulation of calcium levels in the myocardium. In contrast, treatment with the selective inhibitor of ßIPKC, an alternative spliced form of ßIIPKC, had no beneficial effects in these rats. We also found that ßIIV5-3, but not ßIV5-3, improved calcium handling in isolated rat cardiomyocytes and enhanced contractility in isolated rat hearts. In conclusion, our data using an in vivo model of cardiac dysfunction (late-phase hypertrophy), suggest that ßIIPKC contributes to the pathology associated with heart failure and thus an inhibitor of ßIIPKC may be a potential treatment for this disease.


Assuntos
Cardiomegalia/enzimologia , Cardiomegalia/prevenção & controle , Peptídeos/farmacologia , Proteína Quinase C/antagonistas & inibidores , Inibidores de Proteínas Quinases/farmacologia , Sequência de Aminoácidos , Animais , Cálcio/metabolismo , Cardiomegalia/mortalidade , Cardiomiopatias/metabolismo , Cardiomiopatias/patologia , Modelos Animais de Doenças , Fibrose , Insuficiência Cardíaca/metabolismo , Insuficiência Cardíaca/mortalidade , Insuficiência Cardíaca/prevenção & controle , Masculino , Contração Miocárdica/efeitos dos fármacos , Miocárdio/metabolismo , Miocárdio/patologia , Miócitos Cardíacos/metabolismo , Proteína Quinase C beta , Ratos , Ratos Endogâmicos Dahl , ATPases Transportadoras de Cálcio do Retículo Sarcoplasmático/metabolismo , Trocador de Sódio e Cálcio/metabolismo
6.
Trends Endocrinol Metab ; 20(1): 25-33, 2009 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-19056296

RESUMO

Protein-protein interactions sequester enzymes close to their substrates. Protein kinase C (PKC) is one example of a ubiquitous signaling molecule with effects that are dependent upon localization. Short peptides derived from interaction sites between each PKC isozyme and its receptor for activated C kinase act as highly specific inhibitors and have become available as selective drugs in basic research and animal models of human diseases, such as myocardial infarction and hyperglycemia. Whereas the earlier inhibitory peptides are highly specific, we believe that peptides targeting additional interactions between PKC and selective substrates will generate even more selective tools that regulate different functions of individual isozymes. Here, we discuss the methodologies and applications for identifying selective regulators of PKC.


Assuntos
Desenho de Fármacos , Ativadores de Enzimas/síntese química , Inibidores Enzimáticos/síntese química , Fragmentos de Peptídeos/síntese química , Proteína Quinase C/metabolismo , Sequência de Aminoácidos , Animais , Ativação Enzimática/efeitos dos fármacos , Ativadores de Enzimas/química , Ativadores de Enzimas/farmacologia , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Humanos , Modelos Biológicos , Modelos Moleculares , Dados de Sequência Molecular , Fragmentos de Peptídeos/química , Fragmentos de Peptídeos/farmacologia , Ligação Proteica/efeitos dos fármacos , Proteína Quinase C/fisiologia
7.
J Mol Cell Cardiol ; 46(2): 278-84, 2009 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-18983847

RESUMO

The cardioprotective effects of moderate alcohol consumption have been well documented in animal models and in humans. Protection afforded against ischemia and reperfusion injury (I/R) proceeds through an ischemic preconditioning-like mechanism involving the activation of epsilon protein kinase C (varepsilonPKC) and is dependent on the time and duration of ethanol treatment. However, the substrates of varepsilonPKC and the molecular mechanisms by which the enzyme protects the heart from oxidative damage induced by I/R are not fully described. Using an open-chest model of acute myocardial infarction in vivo, we find that intraperitoneal injection of ethanol (0.5 g/kg) 60 min prior to (but not 15 min prior to) a 30-minute transient ligation of the left anterior descending coronary artery reduced I/R-mediated injury by 57% (measured as a decrease of creatine phosphokinase release into the blood). Only under cardioprotective conditions, ethanol treatment resulted in the translocation of varepsilonPKC to cardiac mitochondria, where the enzyme bound aldehyde dehydrogenase-2 (ALDH2). ALDH2 is an intra-mitochondrial enzyme involved in the detoxification of toxic aldehydes such as 4-hydroxy-2-nonenal (4-HNE) and 4-HNE mediates oxidative damage, at least in part, by covalently modifying and inactivating proteins (by forming 4-HNE adducts). In hearts subjected to I/R after ethanol treatment, the levels of 4-HNE protein adducts were lower and JNK1/2 and ERK1/2 activities were diminished relative to the hearts from rats subjected to I/R in the absence of ethanol. Together, this work provides an insight into the mitochondrial-dependent basis of ethanol-induced and varepsilonPKC-mediated protection from cardiac ischemia, in vivo.


Assuntos
Aldeído Desidrogenase/metabolismo , Etanol/farmacologia , Mitocôndrias Cardíacas/metabolismo , Isquemia Miocárdica/metabolismo , Proteína Quinase C-épsilon/metabolismo , Aldeído-Desidrogenase Mitocondrial , Transporte Biológico/efeitos dos fármacos , Transporte Biológico/fisiologia , Western Blotting , Imunoprecipitação , Precondicionamento Isquêmico Miocárdico , Mitocôndrias Cardíacas/efeitos dos fármacos , Traumatismo por Reperfusão Miocárdica , Estresse Oxidativo
9.
Circ Res ; 97(1): 78-85, 2005 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-15961716

RESUMO

Cardiac ischemia and reperfusion are associated with loss in the activity of the mitochondrial enzyme pyruvate dehydrogenase (PDH). Pharmacological stimulation of PDH activity improves recovery in contractile function during reperfusion. Signaling mechanisms that control inhibition and reactivation of PDH during reperfusion were therefore investigated. Using an isolated rat heart model, we observed ischemia-induced PDH inhibition with only partial recovery evident on reperfusion. Translocation of the redox-sensitive delta-isoform of protein kinase C (PKC) to the mitochondria occurred during reperfusion. Inhibition of this process resulted in full recovery of PDH activity. Infusion of the deltaPKC activator H2O2 during normoxic perfusion, to mimic one aspect of cardiac reperfusion, resulted in loss in PDH activity that was largely attributable to translocation of deltaPKC to the mitochondria. Evidence indicates that reperfusion-induced translocation of deltaPKC is associated with phosphorylation of the alphaE1 subunit of PDH. A potential mechanism is provided by in vitro data demonstrating that deltaPKC specifically interacts with and phosphorylates pyruvate dehydrogenase kinase (PDK)2. Importantly, this results in activation of PDK2, an enzyme capable of phosphorylating and inhibiting PDH. Thus, translocation of deltaPKC to the mitochondria during reperfusion likely results in activation of PDK2 and phosphorylation-dependent inhibition of PDH.


Assuntos
Mitocôndrias Cardíacas/enzimologia , Reperfusão Miocárdica , Proteína Quinase C/metabolismo , Proteínas Quinases/metabolismo , Complexo Piruvato Desidrogenase/antagonistas & inibidores , Animais , Ativação Enzimática , Peróxido de Hidrogênio/farmacologia , Masculino , Fosforilação , Proteína Quinase C-delta , Proteínas Serina-Treonina Quinases , Transporte Proteico , Piruvato Desidrogenase Quinase de Transferência de Acetil , Ratos , Ratos Sprague-Dawley
10.
Cardiovasc Res ; 70(2): 222-30, 2006 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-16635641

RESUMO

Ischemic heart disease is the leading cause of morbidity and mortality in the western world. Ischemic damage can occur by acute myocardial infarction, stable angina, cardiac stunning, and myocardial hibernation. In addition, 'scheduled' ischemic events, occurring during cardiac surgery, heart transplantation, and elective angioplasty, can also result in cardiac damage. Ischemic or pharmacological preconditioning can decrease the extent of damage to the myocardium. Although the mechanism of preconditioning-mediated cardioprotection is not fully understood, epsilonPKC has been implicated as a critical mediator of this process in animal studies. The use of isozyme-specific pharmacological tools has permitted a better elucidation of the upstream stimuli and the downstream transducers of epsilonPKC in the pathways leading to cardioprotection. While little is known about the role of epsilonPKC in these pathways in humans, animal studies suggest a potential therapeutic role of epsilonPKC. This review will focus on the role of epsilonPKC in cardiac protection and on the signal transduction cascades that have been implicated in this protection.


Assuntos
Precondicionamento Isquêmico Miocárdico , Isquemia Miocárdica/enzimologia , Miocárdio/enzimologia , Proteína Quinase C-épsilon/fisiologia , Transdução de Sinais/fisiologia , Animais , Ativadores de Enzimas/uso terapêutico , Transplante de Coração , Humanos , Isquemia Miocárdica/tratamento farmacológico , Proteína Quinase C-épsilon/antagonistas & inibidores , Espécies Reativas de Oxigênio/metabolismo , Receptores de Quinase C Ativada , Receptores de Superfície Celular/metabolismo
11.
Int J Parasitol Drugs Drug Resist ; 6(1): 74-84, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-27054066

RESUMO

Parasitic diseases cause ∼ 500,000 deaths annually and remain a major challenge for therapeutic development. Using a rational design based approach, we developed peptide inhibitors with anti-parasitic activity that were derived from the sequences of parasite scaffold proteins LACK (Leishmania's receptor for activated C-kinase) and TRACK (Trypanosoma receptor for activated C-kinase). We hypothesized that sequences in LACK and TRACK that are conserved in the parasites, but not in the mammalian ortholog, RACK (Receptor for activated C-kinase), may be interaction sites for signaling proteins that are critical for the parasites' viability. One of these peptides exhibited leishmanicidal and trypanocidal activity in culture. Moreover, in infected mice, this peptide was also effective in reducing parasitemia and increasing survival without toxic effects. The identified peptide is a promising new anti-parasitic drug lead, as its unique features may limit toxicity and drug-resistance, thus overcoming central limitations of most anti-parasitic drugs.


Assuntos
Leishmania/efeitos dos fármacos , Peptídeos/síntese química , Peptídeos/farmacologia , Proteínas de Protozoários/antagonistas & inibidores , Receptores de Superfície Celular/antagonistas & inibidores , Tripanossomicidas/farmacologia , Trypanosoma/efeitos dos fármacos , Sequência de Aminoácidos , Animais , Antígenos de Protozoários/química , Desenho de Fármacos , Leishmania/química , Leishmania/genética , Leishmaniose/tratamento farmacológico , Leishmaniose/parasitologia , Camundongos , Parasitemia/tratamento farmacológico , Peptídeos/administração & dosagem , Proteínas de Protozoários/química , Receptores de Quinase C Ativada , Receptores de Superfície Celular/química , Alinhamento de Sequência , Tripanossomicidas/administração & dosagem , Tripanossomicidas/química , Trypanosoma/genética , Tripanossomíase/tratamento farmacológico , Tripanossomíase/parasitologia
12.
Radiat Res ; 178(1): 69-74, 2012 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-22404739

RESUMO

Radiation-induced dermatitis is a debilitating clinical problem in cancer patients undergoing cancer radiation therapy. It is also a possible outcome of exposure to high levels of radiation due to accident or hostile activity. We report that activation of aldehyde dehydrogenase 2 (ALDH2) enzymatic activity using the allosteric agonist, Alda-1, significantly reduced 4-hydroxynonenal adducts accumulation, delayed the onset of radiation dermatitis and substantially reduced symptoms in a clinically-relevant model of radiation-induced dermatitis. Importantly, Alda-1 did not radioprotect tumors in mice. Rather, it increased the sensitivity of the tumors to radiation therapy. This is the first report of reactive aldehydes playing a role in the intrinsic radiosensitivity of normal and tumor tissues. Our findings suggest that ALDH2 represents a novel target for the treatment of radiation dermatitis without reducing the benefit of radiotherapy.


Assuntos
Aldeído Desidrogenase/metabolismo , Benzamidas/farmacologia , Benzodioxóis/farmacologia , Radiodermite/tratamento farmacológico , Aldeído-Desidrogenase Mitocondrial , Aldeídos/metabolismo , Animais , Benzamidas/administração & dosagem , Benzodioxóis/administração & dosagem , Ativação Enzimática , Masculino , Camundongos , Camundongos Endogâmicos C3H , Camundongos Endogâmicos C57BL , Radiodermite/enzimologia , Pele/enzimologia , Pele/patologia
13.
J Hematol Oncol ; 4: 49, 2011 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-22128838

RESUMO

Most non-Hodgkin's lymphomas (NHL) initially respond to chemotherapy, but relapse is common and treatment is often limited by chemotherapy-related toxicity. Bortezomib, is a highly selective proteasome inhibitor with anti-NHL activity; it is currently FDA approved for second-line treatment of mantle cell lymphoma (MCL). Bortezomib exerts its activity in part through the generation of reactive oxygen species (ROS) and also by the induction of apoptosis.We previously validated CD22 as a potential target in treating NHL and have shown that the anti-CD22 ligand blocking antibody, HB22.7, has significant independent lymphomacidal properties in NHL xenograft models. We sought to determine whether or not these agents would work synergistically to enhance cytotoxicity. Our results indicate that treatment of NHL cell lines with HB22.7 six hours prior to bortezomib significantly diminished cell viability. These effects were not seen when the agents were administered alone or when bortezomib was administered prior to HB22.7. Additionally, HB22.7 treatment prior to bortezomib increased apoptosis in part through enhanced ROS generation. Finally, in a mouse xenograft model, administration of HB22.7 followed 24 hours later by bortezomib resulted in 23% smaller tumor volumes and 20% enhanced survival compared to treatment with the reverse sequence. Despite the increased efficacy of HB22.7 treatment followed by bortezomib, there was no corresponding decrease in peripheral blood cell counts, indicating no increase in toxicity. Our results suggest that pre-treatment with HB22.7 increases bortezomib cytotoxicity, in part through increased reactive oxygen species and apoptosis, and that this sequential treatment combination has robust efficacy in vivo.


Assuntos
Anticorpos Monoclonais/farmacologia , Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Ácidos Borônicos/farmacologia , Linfoma de Burkitt/tratamento farmacológico , Linfoma de Célula do Manto/tratamento farmacológico , Pirazinas/farmacologia , Lectina 2 Semelhante a Ig de Ligação ao Ácido Siálico/imunologia , Animais , Anticorpos Monoclonais/imunologia , Protocolos de Quimioterapia Combinada Antineoplásica/imunologia , Apoptose/efeitos dos fármacos , Bortezomib , Linhagem Celular Tumoral , Sinergismo Farmacológico , Feminino , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Espécies Reativas de Oxigênio/metabolismo , Ensaios Antitumorais Modelo de Xenoenxerto
14.
Cardiovasc Res ; 85(2): 385-94, 2010 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-19820255

RESUMO

AIMS: The response of the myocardium to an ischaemic insult is regulated by two highly homologous protein kinase C (PKC) isozymes, delta and epsilonPKC. Here, we determined the spatial and temporal relationships between these two isozymes in the context of ischaemia/reperfusion (I/R) and ischaemic preconditioning (IPC) to better understand their roles in cardioprotection. METHODS AND RESULTS: Using an ex vivo rat model of myocardial infarction, we found that short bouts of ischaemia and reperfusion prior to the prolonged ischaemic event (IPC) diminished deltaPKC translocation by 3.8-fold and increased epsilonPKC accumulation at mitochondria by 16-fold during reperfusion. In addition, total cellular levels of deltaPKC decreased by 60 +/- 2.7% in response to IPC, whereas the levels of epsilonPKC did not significantly change. Prolonged ischaemia induced a 48 +/- 11% decline in the ATP-dependent proteasomal activity and increased the accumulation of misfolded proteins during reperfusion by 192 +/- 32%; both of these events were completely prevented by IPC. Pharmacological inhibition of the proteasome or selective inhibition of epsilonPKC during IPC restored deltaPKC levels at the mitochondria while decreasing epsilonPKC levels, resulting in a loss of IPC-induced protection from I/R. Importantly, increased myocardial injury was the result, in part, of restoring a deltaPKC-mediated I/R pro-apoptotic phenotype by decreasing pro-survival signalling and increasing cytochrome c release into the cytosol. CONCLUSION: Taken together, our findings indicate that IPC prevents I/R injury at reperfusion by protecting ATP-dependent 26S proteasomal function. This decreases the accumulation of the pro-apoptotic kinase, deltaPKC, at cardiac mitochondria, resulting in the accumulation of the pro-survival kinase, epsilonPKC.


Assuntos
Precondicionamento Isquêmico Miocárdico , Traumatismo por Reperfusão Miocárdica/prevenção & controle , Complexo de Endopeptidases do Proteassoma/metabolismo , Proteína Quinase C-delta/metabolismo , Trifosfato de Adenosina/fisiologia , Animais , Citocromos c/metabolismo , Mitocôndrias Cardíacas/metabolismo , Proteína Quinase C-épsilon/metabolismo , Transporte Proteico , Proteínas Proto-Oncogênicas c-akt/metabolismo , Ratos , Espécies Reativas de Oxigênio/metabolismo
15.
Cardiovasc Res ; 88(1): 83-92, 2010 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-20558438

RESUMO

AIMS: Protein kinase C epsilon (PKCepsilon) is critical for cardiac protection from ischaemia and reperfusion (IR) injury. PKCepsilon substrates that mediate cytoprotection reside in the mitochondria. However, the mechanism enabling mitochondrial translocation and import of PKCepsilon to enable phosphorylation of these substrates is not known. Heat shock protein 90 (HSP90) is a cytoprotective protein chaperone that participates in mitochondrial import of a number of proteins. Here, we investigated the role of HSP90 in mitochondrial import of PKCepsilon. METHODS AND RESULTS: Using an ex vivo perfused rat heart model of IR, we found that PKCepsilon translocates from the cytosol to the mitochondrial fraction following IR. Immunogold electron microscopy and mitochondrial fractionation demonstrated that following IR, mitochondrial PKCepsilon is localized within the mitochondria, on the inner mitochondrial membrane. Pharmacological inhibition of HSP90 prevented IR-induced interaction between PKCepsilon and the translocase of the outer membrane (Tom20), reduced mitochondrial import of PKCepsilon, and increased necrotic cell death by approximately 70%. Using a rational approach, we designed a 7-amino acid peptide activator of PKCepsilon, derived from an HSP90 homologous sequence located in the C2 domain of PKCepsilon (termed psiepsilonHSP90). Treatment with this peptide (conjugated to the cell permeating TAT protein-derived peptide, TAT(47-57)) increased PKCepsilon-HSP90 protein-protein interaction, enhanced mitochondrial translocation of PKCepsilon, increased phosphorylation and activity of an intra-mitochondrial PKCepsilon substrate, aldehyde dehydrogenase 2, and reduced cardiac injury in ex vivo and in vivo models of myocardial infarction. CONCLUSION: Our results suggest that HSP90-mediated mitochondrial import of PKCepsilon plays an important role in the protection of the myocardium from IR injury.


Assuntos
Proteínas de Choque Térmico HSP90/metabolismo , Mitocôndrias Cardíacas/enzimologia , Traumatismo por Reperfusão Miocárdica/prevenção & controle , Miocárdio/enzimologia , Proteína Quinase C-épsilon/metabolismo , Aldeído Desidrogenase/metabolismo , Aldeído-Desidrogenase Mitocondrial , Sequência de Aminoácidos , Animais , Citoproteção , Modelos Animais de Doenças , Desenho de Fármacos , Ativação Enzimática , Ativadores de Enzimas/química , Ativadores de Enzimas/farmacologia , Humanos , Masculino , Proteínas de Membrana Transportadoras , Mitocôndrias Cardíacas/efeitos dos fármacos , Mitocôndrias Cardíacas/patologia , Membranas Mitocondriais/enzimologia , Proteínas do Complexo de Importação de Proteína Precursora Mitocondrial , Proteínas Mitocondriais/metabolismo , Dados de Sequência Molecular , Contração Miocárdica , Traumatismo por Reperfusão Miocárdica/enzimologia , Traumatismo por Reperfusão Miocárdica/patologia , Traumatismo por Reperfusão Miocárdica/fisiopatologia , Miocárdio/patologia , Necrose , Oligopeptídeos/química , Oligopeptídeos/farmacologia , Fosforilação , Ligação Proteica , Transporte Proteico , Ratos , Ratos Wistar , Receptores de Superfície Celular , Receptores Citoplasmáticos e Nucleares/metabolismo , Recuperação de Função Fisiológica , Alinhamento de Sequência
16.
Transpl Immunol ; 23(1-2): 65-70, 2010 May.
Artigo em Inglês | MEDLINE | ID: mdl-20403439

RESUMO

BACKGROUND: We aimed to compare two techniques of heterotopic heart transplantation in rats. Non-volume-loaded (NL) and volume-loaded (VL) models were tested for their physiologic and immunologic properties to assess their suitability for transplant studies. METHODS: Syngeneic heterotopic heart transplants were performed according to the techniques previously described by Ono (NL) and Yokoyama (VL). Grafts were followed over 90 days with sequential echocardiography. Ex-vivo Langendorff perfusion was used to gain functional data. Allogeneic heart transplants were done to determine whether chronic allograft vasculopathy (CAV) develops at a different pace in both transplant models. RESULTS: The ischemic time during surgery was significantly longer using the VL model (p<0.001). The LV diameter of NL hearts decreased over time while that of the VL model significantly increased (p=0.004 on POD 90). Mean LV developed pressure and (dP/dt)max were significantly higher with the NL model (61.1+/-8.5 mmHg and 4261.7+/-419.6 mmHg/s) than with VL hearts (19.9+/-16.5 mmHg; p=0.011 and 924.8+/-605.6 mmHg/s; p<0.001). The mean weight of NL hearts (0.45+/-0.03 g) was significantly less than that of VL hearts (1.21+/-0.16 g, p<0.001). Histology of syngeneic NL grafts showed healthy, but partly atrophic myocardium, whereas the LV myocardium of VL hearts showed dilation and scarring typical for chronic ischemic injury. Heart allografts similarly developed CAV with luminal narrowing of 37.2+/-16.6% (NL) and 34.4+/-21.4% (VL), respectively by POD 90 (p=0.807). CONCLUSIONS: Since the coronary arteries in the VL model get perfused with partly deoxygenated blood, the myocardium suffers from chronic ischemic injury. We recommend using the NL model in preclinical transplant studies.


Assuntos
Volume Cardíaco/fisiologia , Transplante de Coração/métodos , Transplante Heterotópico , Animais , Aorta Abdominal/transplante , Aorta Torácica/diagnóstico por imagem , Diástole , Ecocardiografia , Coração/fisiopatologia , Masculino , Modelos Animais , Miocárdio/patologia , Ratos , Veia Cava Inferior/patologia
18.
Annu Rev Pharmacol Toxicol ; 48: 569-99, 2008.
Artigo em Inglês | MEDLINE | ID: mdl-17919087

RESUMO

Cardiovascular disease is the leading cause of death in the United States. Therefore, identifying therapeutic targets is a major focus of current research. Protein kinase C (PKC), a family of serine/threonine kinases, has been identified as playing a role in many of the pathologies of heart disease. However, the lack of specific PKC regulators and the ubiquitous expression and normal physiological functions of the 11 PKC isozymes has made drug development a challenge. Here we discuss the validity of therapeutically targeting PKC, an intracellular signaling enzyme. We describe PKC structure, function, and distribution in the healthy and diseased heart, as well as the development of rationally designed isozyme-selective regulators of PKC functions. The review focuses on the roles of specific PKC isozymes in atherosclerosis, fibrosis, and cardiac hypertrophy, and examines principles of pharmacology as they pertain to regulators of signaling cascades associated with these diseases.


Assuntos
Doenças Cardiovasculares/tratamento farmacológico , Sistemas de Liberação de Medicamentos , Proteína Quinase C/efeitos dos fármacos , Animais , Doenças Cardiovasculares/fisiopatologia , Doença Crônica , Desenho de Fármacos , Humanos , Isoenzimas/metabolismo , Proteína Quinase C/metabolismo , Transdução de Sinais
19.
Ther Adv Cardiovasc Dis ; 2(6): 469-83, 2008 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-19124442

RESUMO

The physiological effects of ethanol are dependent upon the amount and duration of consumption. Chronic excessive consumption can lead to diseases such as liver cirrhosis, and cardiac arrhythmias, while chronic moderate consumption can have therapeutic effects on the cardiovascular system. Recently, it has also been observed that acute administration of ethanol to animals prior to an ischemic event provides significant protection to the heart. This review focuses on the different modalities of chronic vs. acute ethanol consumption and discusses recent evidence for a protective effect of acute ethanol exposure and the possible use of ethanol as a therapeutic agent.


Assuntos
Depressores do Sistema Nervoso Central/uso terapêutico , Etanol/uso terapêutico , Isquemia Miocárdica/tratamento farmacológico , Isquemia Miocárdica/metabolismo , Proteína Quinase C/metabolismo , Animais , Humanos , Precondicionamento Isquêmico Miocárdico
20.
Science ; 321(5895): 1493-5, 2008 Sep 12.
Artigo em Inglês | MEDLINE | ID: mdl-18787169

RESUMO

There is substantial interest in the development of drugs that limit the extent of ischemia-induced cardiac damage caused by myocardial infarction or by certain surgical procedures. Here, using an unbiased proteomic search, we identified mitochondrial aldehyde dehydrogenase 2 (ALDH2) as an enzyme whose activation correlates with reduced ischemic heart damage in rodent models. A high-throughput screen yielded a small-molecule activator of ALDH2 (Alda-1) that, when administered to rats before an ischemic event, reduced infarct size by 60%, most likely through its inhibitory effect on the formation of cytotoxic aldehydes. In vitro, Alda-1 was a particularly effective activator of ALDH2*2, an inactive mutant form of the enzyme that is found in 40% of East Asian populations. Thus, pharmacologic enhancement of ALDH2 activity may be useful for patients with wild-type or mutant ALDH2 who are subjected to cardiac ischemia, such as during coronary bypass surgery.


Assuntos
Aldeído Desidrogenase/metabolismo , Benzamidas/farmacologia , Benzodioxóis/farmacologia , Cardiotônicos/farmacologia , Proteínas Mitocondriais/metabolismo , Infarto do Miocárdio/prevenção & controle , Traumatismo por Reperfusão Miocárdica/enzimologia , Miocárdio/enzimologia , Aldeído Desidrogenase/antagonistas & inibidores , Aldeído-Desidrogenase Mitocondrial , Aldeídos/metabolismo , Sequência de Aminoácidos , Animais , Cianamida/farmacologia , Ativação Enzimática , Etanol/farmacologia , Precondicionamento Isquêmico Miocárdico , Proteínas Mitocondriais/agonistas , Proteínas Mitocondriais/antagonistas & inibidores , Dados de Sequência Molecular , Infarto do Miocárdio/enzimologia , Infarto do Miocárdio/patologia , Miocárdio/patologia , Nitroglicerina/farmacologia , Fosforilação , Proteína Quinase C-épsilon/metabolismo , Proteômica , Ratos , Ratos Wistar
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