Differential control and function of Arabidopsis ProDH1 and ProDH2 genes on infection with biotrophic and necrotrophic pathogens.

Arabidopsis contains two proline dehydrogenase (ProDH) genes, ProDH1 and ProDH2, encoding for homologous and functional isoenzymes. Although ProDH1 has been studied extensively, especially under abiotic stress, ProDH2 has only started to be analysed in recent years. These genes display distinctive expression patterns and show weak transcriptional co-regulation, but are both activated in pathogen-infected tissues. We have demonstrated previously that Arabidopsis plants with silenced ProDH1/2 expression fail to trigger defences against the hemibiotrophic bacterial pathogen Pseudomonas syringae pv. tomato AvrRpm1 (Pst-AvrRpm1), and that ProDH1 and ProDH2 are differentially regulated by salicylic acid (SA). In the current work, we used prodh1 and prodh2 single-mutant plants to assess the particular contribution of each gene to resistance against Pst-AvrRpm1 and the necrotrophic fungal pathogen Botrytis cinerea. In addition, we studied the sensitivity of ProDH1 and ProDH2 to the jasmonic acid (JA) defence pathway. We found that ProDH1 and ProDH2 are both necessary to achieve maximum resistance against Pst-AvrRpm1 and B. cinerea. However, ProDH2 has a major effect on early restriction of B. cinerea growth. Interestingly, ProDH1 is up-regulated by SA and JA, whereas ProDH2 is only activated by JA, and both genes display transcriptional inter-regulation at basal and infection conditions. These studies provide the first evidence of the contribution of ProDH2 to disease resistance, and describe the differential regulation and non-redundant but complementary function of both enzyme isoforms in infected tissues, providing support for a fundamental role of ProDH in the control of biotrophic and necrotrophic pathogens.

Arabidopsis Proline Dehydrogenase Contributes to Flagellin-Mediated PAMP-Triggered Immunity by Affecting RBOHD.

Plants activate different defense systems to counteract the attack of microbial pathogens. Among them, the recognition of conserved microbial- or pathogen-associated molecular patterns (MAMPs or PAMPs) by pattern-recognition receptors stimulates MAMP- or PAMP-triggered immunity (PTI). In recent years, the elicitors, receptors, and signaling pathways leading to PTI have been extensively studied. However, the contribution of organelles to this program deserves further characterization. Here, we studied how processes altering the mitochondrial electron transport chain (mETC) influence PTI establishment. With particular emphasis, we evaluated the effect of proline dehydrogenase (ProDH), an enzyme that can load electrons into the mETC and regulate the cellular redox state. We found that mETC uncouplers (antimycin or rotenone) and manganese superoxide dismutase deficiency impair flg22-induced responses such as accumulation of reactive oxygen species (ROS) and bacterial growth limitation. ProDH mutants also reduce these defenses, decreasing callose deposition as well. Using ProDH inhibitors and ProDH inducers (exogenous Pro treatment), we showed that this enzyme modulates the generation of ROS by the plasma membrane respiratory burst NADPH oxidase homolog D. In this way, we contribute to the understanding of mitochondrial activities influencing early and late PTI responses and the coordination of the redox-associated mitochondrial enzyme ProDH with defense events initiated at the plasma membrane.

Relationship between polymorphisms in the proline dehydrogenase gene and schizophrenia risk.

Previous studies have suggested that an association exists between the proline dehydrogenase gene (PRODH) and increased schizophrenia risk. We examined the prevalence of the PRODH 757C/T (Arg185Trp), 1766A/G (Gly521Arg), and 1852G/A (intronic mutation) polymorphisms in 175 patients with schizophrenia and 185 control subjects. All subjects were of Iranian ancestry. The PRODH 757TT, 1852AA, and 1766GG genotypes were associated with an increased risk of schizophrenia (odds ratio = 1.38, 95% confidence interval: 0.88-2.16, P = 0.001, P = 0.001, respectively). The activity alleles in the PRODH genotype combinations were associated with an increased risk of schizophrenia (haplotype analysis, TAG genotype P = 0.007). Our findings support a major role for the PRODH 757TT, 1766GG, and 1852AA genotypes alone and in combination for schizophrenia susceptibility.

Comparative analysis of non-adherence to medication treatment for systemic arterial hypertension in urban and rural populations / Análise comparativa da não adesão ao tratamento medicamentoso da hipertensão arterial sistêmica em população urbana e rural / Análisis comparativa de la no adhesión al tratamiento medicamentoso de la hipertensión arterial sistémica en población urbana y rural

OBJECTIVE: to evaluate the indexes and the main factors associated with non-adherence to medication treatment for systemic arterial hypertension between urban and rural areas. METHOD: analytical study based on an epidemiological survey with a sample of 247 hypertensive residents of rural and urban areas, with application of a socio-demographic and economic questionnaire, and treatment adherence assessment. The Pearson's Chi-square test was used and the odds ratio (OD) was calculated to analyze the factors related to non-adherence. RESULTS: the prevalence of non-adherence was 61.9% and it was higher in urban areas (63.4%). Factors significantly associated with non-adherence were: male gender (OR=1.95; 95% CI 1.08-3.50), age 20-59 years old (OR=2.51; 95% CI 1.44-4.39), low economic status (OR=1.95; 95% CI 1.09-3.47), alcohol consumption (OR=5.92, 95% CI 1.73-20.21), short time of hypertension diagnosis (OR=3.07; 95% CI 1.35-6.96) and not attending the health service for routine consultations (OR=2.45; 1.35-4.42). CONCLUSION: the socio-demographic/economic characteristics, lifestyle habits and how to relate to health services were the factors that presented association with non-adherence regardless of the place of residence. .

OBJETIVO: avaliar os índices e os principais fatores associados a não adesão ao tratamento medicamentoso da hipertensão arterial sistêmica, entre área urbana e rural. MÉTODO: estudo analítico baseado em inquérito epidemiológico, realizado com amostra de 247 hipertensos moradores das áreas rural e urbana, com aplicação de questionário sociodemográfico, econômico e avaliação da adesão. Foi utilizado o teste quiquadrado de Pearson e calculado o Odds Ratio (OD) para análise dos fatores relacionados a não adesão. RESULTADOS: a prevalência da não adesão foi de 61,9%, sendo maior na área urbana (63,4%). Os fatores que apresentaram associação estatisticamente significativa com a não adesão foram: gênero masculino (OR=1,95; IC95% 1,08-3,50), faixa etária entre 20 e 59 anos (OR=2,51; IC95% 1,44-4,39), baixa classe econômica (OR=1,95; IC95% 1,09-3,47), etilismo (OR=5,92; IC 95% 1,73-20,21), tempo curto de diagnóstico de hipertensão (OR=3,07; IC95% 1,35-6,96) e não procura pelo serviço de saúde para consultas de rotina (OR=2,45; 1,35-4,42). CONCLUSÃO: as características sociodemográficas, econômicas, hábitos de vida e o modo de relacionar-se com os serviços de saúde foram os fatores que apresentaram associação com a não adesão, independentemente do local de residência. .

OBJETIVO: evaluar los índices y los principales factores asociados a la no adhesión al tratamiento medicamentoso de la hipertensión arterial sistémica entre área urbana y rural. MÉTODO: estudio analítico basado en investigación epidemiológica desarrollada con una muestra de 247 hipertensos moradores del área rural y urbana, con aplicación de un cuestionario sociodemográfico, económico y evaluación de la adhesión. Fue utilizado la prueba chi-cuadrado de Pearson y calculado el odds ratio (OD) para análisis de los factores relacionados a la no adhesión. RESULTADOS: la prevalencia de la no adhesión correspondió a 61,9%, siendo mayor en el área urbana (63,4%). Los factores que mostraron asociación estadísticamente significativa con la no adhesión fueron: género masculino (OR=1,95; IC95% 1,08-3,50), rango de edad entre 20 a 59 años (OR=2,51; IC95% 1,44-4,39), clase económica baja (OR=1,95; IC95% 1,09-3,47), etilismo (OR=5,92; IC 95% 1,73-20,21), tiempo corto de diagnóstico de hipertensión (OR=3,07; IC95% 1,35-6,96) y no procurar el servicio de salud para consultas de rutina (OR=2,45; 1,35-4,42). CONCLUSIÓN: las características sociodemográficas/económicas, hábitos de vida y el modo de relacionar con los servicios de salud fueron los factores que mostraron asociación con la no adhesión independientemente del local de residencia. .

PRODH polymorphisms, cortical volumes and thickness in schizophrenia.

Schizophrenia is a neurodevelopmental disorder with high heritability. Several lines of evidence indicate that the PRODH gene may be related to the disorder. Therefore, our study investigates the effects of 12 polymorphisms of PRODH on schizophrenia and its phenotypes. To further evaluate the roles of the associated variants in the disorder, we have conducted magnetic resonance imaging (MRI) scans to assess cortical volumes and thicknesses. A total of 192 patients were evaluated using the Structured Clinical Interview for DSM-IV (SCID), Positive and Negative Syndrome Scale (PANSS), Calgary Depression Scale, Global Assessment of Functioning (GAF) and Clinical Global Impression (CGI) instruments. The study included 179 controls paired by age and gender. The samples were genotyped using the real-time polymerase chain reaction (PCR), restriction fragment length polymorphism (RFLP)-PCR and Sanger sequencing methods. A sample of 138 patients and 34 healthy controls underwent MRI scans. One polymorphism was associated with schizophrenia (rs2904552), with the G-allele more frequent in patients than in controls. This polymorphism is likely functional, as predicted by PolyPhen and SIFT, but it was not associated with brain morphology in our study. In summary, we report a functional PRODH variant associated with schizophrenia that may have a neurochemical impact, altering brain function, but is not responsible for the cortical reductions found in the disorder.

Proline dehydrogenase regulates redox state and respiratory metabolism in Trypanosoma cruzi.

Over the past three decades, L-proline has become recognized as an important metabolite for trypanosomatids. It is involved in a number of key processes, including energy metabolism, resistance to oxidative and nutritional stress and osmoregulation. In addition, this amino acid supports critical parasite life cycle processes by acting as an energy source, thus enabling host-cell invasion by the parasite and subsequent parasite differentiation. In this paper, we demonstrate that L-proline is oxidized to Δ(1)-pyrroline-5-carboxylate (P5C) by the enzyme proline dehydrogenase (TcPRODH, E.C. 1.5.99.8) localized in Trypanosoma cruzi mitochondria. When expressed in its active form in Escherichia coli, TcPRODH exhibits a Km of 16.58±1.69 µM and a Vmax of 66±2 nmol/min mg. Furthermore, we demonstrate that TcPRODH is a FAD-dependent dimeric state protein. TcPRODH mRNA and protein expression are strongly upregulated in the intracellular epimastigote, a stage which requires an external supply of proline. In addition, when Saccharomyces cerevisiae null mutants for this gene (PUT1) were complemented with the TcPRODH gene, diminished free intracellular proline levels and an enhanced sensitivity to oxidative stress in comparison to the null mutant were observed, supporting the hypothesis that free proline accumulation constitutes a defense against oxidative imbalance. Finally, we show that proline oxidation increases cytochrome c oxidase activity in mitochondrial vesicles. Overall, these results demonstrate that TcPRODH is involved in proline-dependant cytoprotection during periods of oxidative imbalance and also shed light on the participation of proline in energy metabolism, which drives critical processes of the T. cruzi life cycle.

Proline dehydrogenase is a positive regulator of cell death in different kingdoms.

Proline dehydrogenase (ProDH) catalyzes the flavin-dependent oxidation of Pro into Δ1-pyrroline-5-carboxylate (P5C). This is the first of the two enzymatic reactions that convert proline (Pro) into glutamic acid (Glu). The P5C thus produced is non-enzymatically transformed into glutamate semialdehyde (GSA), which acts as a substrate of P5C dehydrogenase (P5CDH) to generate Glu. Activation of ProDH can generate different effects depending on the behaviour of other enzymes of this metabolism. Under different conditions it can generate toxic levels of P5C, alter the cellular redox homeostasis and even produce reactive oxygen species (ROS). Recent studies indicate that in Arabidopsis, the enzyme potentiates the oxidative burst and cell death associated to the Hypersensitive Responses (HR). Interestingly, activation of ProDH can also produce harmful effects in other organisms, suggesting that the enzyme may play a conserved role in the control of cell death.

Proline dehydrogenase contributes to pathogen defense in Arabidopsis.

L-proline (Pro) catabolism is activated in plants recovering from abiotic stresses associated with water deprivation. In this catabolic pathway, Pro is converted to glutamate by two reactions catalyzed by proline dehydrogenase (ProDH) and Δ(1)-pyrroline-5-carboxylate dehydrogenase (P5CDH), with Δ(1)-pyrroline-5-carboxylate (P5C) as the intermediate. Alternatively, under certain conditions, the P5C derived from Pro is converted back to Pro by P5C reductase, thus stimulating the Pro-P5C cycle, which may generate reactive oxygen species (ROS) as a consequence of the ProDH activity. We previously observed that Pro biosynthesis is altered in Arabidopsis (Arabidopsis thaliana) tissues that induce the hypersensitive response (HR) in response to Pseudomonas syringae. In this work, we characterized the Pro catabolic pathway and ProDH activity in this model. Induction of ProDH expression was found to be dependent on salicylic acid, and an increase in ProDH activity was detected in cells destined to die. To evaluate the role of ProDH in the HR, ProDH-silenced plants were generated. These plants displayed reduced ROS and cell death levels as well as enhanced susceptibility in response to avirulent pathogens. Interestingly, the early activation of ProDH was accompanied by an increase in P5C reductase but not in P5CDH transcripts, with few changes occurring in the Pro and P5C levels. Therefore, our results suggest that in wild-type plants, ProDH is a defense component contributing to HR and disease resistance, which apparently potentiates the accumulation of ROS. The participation of the Pro-P5C cycle in the latter response is discussed.

Over-expression of genes coding for proline oxidase, riboflavin kinase, cytochrome c oxidase and an MFS transporter induced by acriflavin in Trichophyton rubrum.

Acriflavin (3,6-acridinediamine) and other acridine derivatives act in both prokaryotic and eukaryotic cells at the level of DNA-coiling enzymes (topoisomerases) causing the stabilization of the enzyme-DNA cleavable complex. In order to better understand the mode of action of acriflavin, Differential Display RT-PCR was used to isolate transcripts specifically over-expressed during exposure of Trichophyton rubrum mycelia to this drug. Five transcripts, whose differential expressions were confirmed by Northern blotting, revealed genes not previously described in this dermatophyte. Functional grouping identified putative enzymes possibly involved in the mitochondrial respiratory electron-transport chain and in iron transport. These results may be relevant to our understanding of the molecular events involved in the stress response of T. rubrum to acriflavin.