Interactions between Trypanosoma cruzi Secreted Proteins and Host Cell Signaling Pathways

Chagas disease is one of the prevalent neglected tropical diseases, affecting at least 6-7 million individuals in Latin America. It is caused by the protozoan parasite Trypanosoma cruzi, which is transmitted to vertebrate hosts by blood-sucking insects. After infection, the parasite invades and multiplies in the myocardium, leading to acute myocarditis that kills around 5% of untreated individuals. T. cruzi secretes proteins that manipulate multiple host cell signaling pathways to promote host cell invasion. The primary secreted lysosomal peptidase in T. cruzi is cruzipain, which has been shown to modulate the host immune response. Cruzipain hinders macrophage activation during the early stages of infection by interrupting the NF-kB P65 mediated signaling pathway. This allows the parasite to survive and replicate, and may contribute to the spread of infection in acute Chagas disease. Another secreted protein P21, which is expressed in all of the developmental stages of T. cruzi, has been shown to modulate host phagocytosis signaling pathways. The parasite also secretes soluble factors that exert effects on host extracellular matrix, such as proteolytic degradation of collagens. Finally, secreted phospholipase A from T. cruzi contributes to lipid modifications on host cells and concomitantly activates the PKC signaling pathway. Here, we present a brief review of the interaction between secreted proteins from T cruzi and the host cells, emphasizing the manipulation of host signaling pathways during invasion.Fundação de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES)CNNUniv Fed Sao Paulo, Escola Paulista Med, Dept Microbiol Imunol & Parasitol, Sao Paulo, BrazilUniv Fed Minas Gerais, Inst Ciencias Biol, Dept Biol Geral, Belo Horizonte, MG, BrazilUniv Fed Sao Paulo, Escola Paulista Med, Dept Microbiol Imunol & Parasitol, Sao Paulo, BrazilFAPESP: 07/50551-2FAPESP: 11/51475-3Web of Scienc

Isokinetic assessment of the hip muscles in patients with osteoarthritis of the knee

OBJECTIVES: To evaluate the difference in isokinetic strength of hip muscles between patients with knee osteoarthritis (OA) and matched healthy controls, and to establish the correlation between this isokinetic strength and pain and function in patients with knee OA. METHODS: 25 patients with a diagnosis of unilateral knee OA, 25 patients with bilateral knee OA, and 50 matched controls were evaluated using the visual analog scale for pain, knee Lequesne index, Western Ontario and McMaster Universities questionnaire and an isokinetic test. RESULTS: The groups were matched for age, gender and body mass index. The results of the isokinetic test revealed lower peak torque of the hip in patients with OA of the knee than in the control group for all movements studied. Strong correlations were found between the peak torque, visual analog scale and function. CONCLUSIONS: Patients with OA of the knee exhibit lower isokinetic strength in the hip muscles than healthy control subjects. Strengthening the muscles surrounding the hip joint may help to decrease pain in people with knee OA. Some correlations between pain/function and peak torque were found

Hippocampal biomarkers of fear memory in an animal model of generalized anxiety disorder

Generalized anxiety disorder (GAD) is highly prevalent and incapacitating. Here we used the Carioca High-Conditioned Freezing (CHF) rats, a previously validated animal model for GAD, to identify biomarkers and structural changes in the hippocampus that could be part of the underlying mechanisms of their high-anxiety profile. Spatial and fear memory was assessed in the Morris water maze and passive avoidance test. Serum corticosterone levels, immunofluorescence for glucocorticoid receptors (GR) in the dentate gyrus (DG), and western blotting for hippocampal brain derived neurotrophic factor (BDNF) were performed. Immunohistochemistry for markers of cell proliferation (bromodeoxiuridine/Ki-67), neuroblasts (doublecortin), and cell survival were undertaken in the DG, along with spine staining (Golgi) and dendritic arborization tracing. Hippocampal GABA release was assessed by neurochemical assay. Fear memory was higher among CHF rats whilst spatial learning was preserved. Serum corticosterone levels were increased, with decreased GR expression. No differences were observed in hippocampal cell proliferation/survival, but the number of newborn neurons was decreased, along with their number and length of tertiary dendrites. Increased expression of proBDNF and dendritic spines was observed; lower ratio of GABA release in the hippocampus was also verified. These findings suggest that generalized anxiety/fear could be associated with different hippocampal biomarkers, such as increased spine density, possibly as a compensatory mechanism for the decreased hippocampal number of neuroblasts and dendritic arborization triggered by high corticosterone. Disruption of GABAergic signaling and BDNF impairment are also proposed as part of the hippocampal mechanisms possibly underlying the anxious phenotype of this model

Canagliflozin and renal outcomes in type 2 diabetes and nephropathy

BACKGROUND Type 2 diabetes mellitus is the leading cause of kidney failure worldwide, but few effective long-term treatments are available. In cardiovascular trials of inhibitors of sodium–glucose cotransporter 2 (SGLT2), exploratory results have suggested that such drugs may improve renal outcomes in patients with type 2 diabetes. METHODS In this double-blind, randomized trial, we assigned patients with type 2 diabetes and albuminuric chronic kidney disease to receive canagliflozin, an oral SGLT2 inhibitor, at a dose of 100 mg daily or placebo. All the patients had an estimated glomerular filtration rate (GFR) of 30 to <90 ml per minute per 1.73 m2 of body-surface area and albuminuria (ratio of albumin [mg] to creatinine [g], >300 to 5000) and were treated with renin–angiotensin system blockade. The primary outcome was a composite of end-stage kidney disease (dialysis, transplantation, or a sustained estimated GFR of <15 ml per minute per 1.73 m2), a doubling of the serum creatinine level, or death from renal or cardiovascular causes. Prespecified secondary outcomes were tested hierarchically. RESULTS The trial was stopped early after a planned interim analysis on the recommendation of the data and safety monitoring committee. At that time, 4401 patients had undergone randomization, with a median follow-up of 2.62 years. The relative risk of the primary outcome was 30% lower in the canagliflozin group than in the placebo group, with event rates of 43.2 and 61.2 per 1000 patient-years, respectively (hazard ratio, 0.70; 95% confidence interval [CI], 0.59 to 0.82; P=0.00001). The relative risk of the renal-specific composite of end-stage kidney disease, a doubling of the creatinine level, or death from renal causes was lower by 34% (hazard ratio, 0.66; 95% CI, 0.53 to 0.81; P<0.001), and the relative risk of end-stage kidney disease was lower by 32% (hazard ratio, 0.68; 95% CI, 0.54 to 0.86; P=0.002). The canagliflozin group also had a lower risk of cardiovascular death, myocardial infarction, or stroke (hazard ratio, 0.80; 95% CI, 0.67 to 0.95; P=0.01) and hospitalization for heart failure (hazard ratio, 0.61; 95% CI, 0.47 to 0.80; P<0.001). There were no significant differences in rates of amputation or fracture. CONCLUSIONS In patients with type 2 diabetes and kidney disease, the risk of kidney failure and cardiovascular events was lower in the canagliflozin group than in the placebo group at a median follow-up of 2.62 years

Omecamtiv mecarbil in chronic heart failure with reduced ejection fraction, GALACTIC‐HF: baseline characteristics and comparison with contemporary clinical trials

Aims: The safety and efficacy of the novel selective cardiac myosin activator, omecamtiv mecarbil, in patients with heart failure with reduced ejection fraction (HFrEF) is tested in the Global Approach to Lowering Adverse Cardiac outcomes Through Improving Contractility in Heart Failure (GALACTIC‐HF) trial. Here we describe the baseline characteristics of participants in GALACTIC‐HF and how these compare with other contemporary trials. Methods and Results: Adults with established HFrEF, New York Heart Association functional class (NYHA) ≥ II, EF ≤35%, elevated natriuretic peptides and either current hospitalization for HF or history of hospitalization/ emergency department visit for HF within a year were randomized to either placebo or omecamtiv mecarbil (pharmacokinetic‐guided dosing: 25, 37.5 or 50 mg bid). 8256 patients [male (79%), non‐white (22%), mean age 65 years] were enrolled with a mean EF 27%, ischemic etiology in 54%, NYHA II 53% and III/IV 47%, and median NT‐proBNP 1971 pg/mL. HF therapies at baseline were among the most effectively employed in contemporary HF trials. GALACTIC‐HF randomized patients representative of recent HF registries and trials with substantial numbers of patients also having characteristics understudied in previous trials including more from North America (n = 1386), enrolled as inpatients (n = 2084), systolic blood pressure < 100 mmHg (n = 1127), estimated glomerular filtration rate < 30 mL/min/1.73 m2 (n = 528), and treated with sacubitril‐valsartan at baseline (n = 1594). Conclusions: GALACTIC‐HF enrolled a well‐treated, high‐risk population from both inpatient and outpatient settings, which will provide a definitive evaluation of the efficacy and safety of this novel therapy, as well as informing its potential future implementation

Secretoma E Interactoma Comparativo De Trypanosoma Cruzi E Trypanosoma Rangeli

Chagas disease, a zoonosis caused by the flagellate protozoan Trypanosoma cruzi, is a chronic and systemic parasitic infection that affects approximately 8 million patients in Latin America, being an emerging public health problem due to the lack of immunization and effective chemotherapy. According to recent studies, there are several T. cruzi secreted proteins that interact with the human host during cell invasion. Moreover, several comparative studies with T. rangeli, non-pathogenic for humans, have been performed in order to identify proteins directly involved in the pathogenesis of the disease. Regarding identification and large-scale protein characterization, bioinformatics has grown significantly with the evolution of specific computational softwares for proteins prediction. In this study, we present an integrated computational network in order to analyze secreted proteins of both species. Additionally, we propose an interactome and phylogenetic trees of some selected proteins. In T. cruzi, we identified 463 exclusively secreted proteins; compared to 202 in T. rangeli. Among the secreted proteins identified in T. cruzi, we found several trans-sialidases, mucins, MASPs, proteins with phospholipase 2 domain (PLA2-like) and Hsp70 domain (Hsp70-like) which were previously characterized by other studies and were demonstrated to be related to T. cruzi virulence. Proteins found in T. rangeli were related to protozoan metabolism as carboxylases and phosphatases. Furthermore, there were also proteins that may interact with the human's immune system such as heat shock and MASP proteins, but in a smaller number compared to T. cruzi. Finally, another selected protein, HYOU1, an orthologous human protein to the identified Hsp70-like protein, present in both species, showed interaction with other proteins of the immune system. These results will pave the way for a better understanding of the pathophysiology of Chagas disease and ultimately leading to the identification of molecular targets for drug development.A doença de Chagas, zoonose causada pelo protozoário flagelado Trypanosoma cruzi, é uma infecção parasitária crônica e sistêmica que afeta cerca de 8 milhões de pacientes na América Latina, sendo um problema de saúde emergente devido a ausência de imunização e quimioterapia eficaz. De acordo com estudos recentes, existem diversas proteínas secretadas de T. cruzi que interagem com o hospedeiro humano durante a invasão celular. Além disso, foram realizados diversos estudos comparativos com a espécie T. rangeli, não patogênica em humanos, para identificar proteínas diretamente envolvidas na patogênese da doença. Para identificação e caracterização proteica em grande escala, a bioinformática tem crescido expressamente com a evolução de programas computacionais específicos para análise e predição de proteínas. Neste trabalho, nós apresentamos uma rede computacional integrada para análise de proteínas secretadas de ambas as espécies. Além disso, foram propostos interactomas e construção de árvores filogenéticas das proteínas selecionadas. Em T. cruzi, nós identificamos 463 proteínas exclusivamente secretadas; comparado com 202 em T. rangeli. Dentre as proteínas secretadas identificadas em T. cruzi, foram encontradas diversas trans-sialidades, mucinas, MASPs, proteínas com domínio em fosfolipase 2 (PLA2) e Hsp70 (Hsp70-like) que foram previamente caracterizadas por outros estudos e demonstraram apresentar relação com a virulência de T. cruzi. As proteínas encontradas em T. rangeli estavam relacionadas ao metabolismo do protozoário como carboxilases, fosfatases. Também havia proteínas que interagiam com o sistema imune do homem como proteínas heat shock e MASP, porém em menor número em comparação com T. cruzi. Adicionalmente, com a proposta de interactoma, foi observado que as proteínas do parasita podem interferir no hospedeiro humano. A proteína HYOU1, proteína ortóloga humana da proteína Hsp70-like identificada, presente nas duas espécies, demonstrou interação com outras proteínas do sistema imune, por exemplo. Estes resultados poderão abrir caminho para uma melhor compreensão da fisiopatologia da doença de Chagas e, em última análise, conduzirão à identificação de alvos moleculares para o desenvolvimento de fármacos.Dados abertos - Sucupira - Teses e dissertações (2017

Interactions between Trypanosoma cruzi secreted proteins and host cell signaling pathways

Chagas disease is one of the prevalent neglected tropical diseases, affecting at least 6-7 million individuals in Latin America. It is caused by the protozoan parasite Trypanosoma cruzi (T. cruzi), which is transmitted to vertebrate hosts by blood-sucking insects. After infection, the parasite invades and multiplies in the myocardium, leading to acute myocarditis that kills around 5% of untreated individuals. T. cruzi secretes proteins that manipulate multiple host cell signaling pathways to promote host cell invasion. The primary secreted lysosomal peptidase in T. cruzi is cruzipain, which has been shown to modulate the host immune response. Cruzipain hinders macrophage activation during the early stages of infection by interrupting the NF-kB P65 mediated signaling pathway. This allows the parasite to survive and replicate, and may contribute to the spread of infection in acute Chagas disease. Another secreted protein P21, which is expressed in all of the developmental stages of T. cruzi, has been shown to modulate host phagocytosis signaling pathways. The parasite also secretes soluble factors that exert effects on host extracellular matrix, such as proteolytic degradation of collagens. Finally, secreted phospholipase A from T. cruzi contributes to lipid modifications on host cells and concomitantly activates the PKC signaling pathway. Here we present a brief review of the interaction between secreted proteins from T. cruzi and the host cells, emphasizing the manipulation of host signaling pathways during invasion