The molecular pruning of a phosphoramidate peptidomimetic inhibitor of prostate-specific membrane antigen

To identify the pharmacophore of a phosphoramidate peptidomimetic inhibitor of prostate-specific membrane antigen (PSMA), a small analog library was designed and screened for inhibitory potency against PSMA. The design of the lead inhibitor was based upon N-acyl derivatives of endogenous substrate folyl-gamma-Glu and incorporates a phosphoramidate group to interact with the PSMA catalytic zinc atoms. The scope of the analog library was designed to test the importance of various functional groups to the inhibitory potency of the lead phosphoramidate. The IC(50) for the lead phosphoramidate inhibitor was 35 nM while the IC(50) values for the analog library presented a range from 0.86 nM to 4.1 microM. Computational docking, utilizing a recently solved X-ray crystal structure of the recombinant protein, along with enzyme inhibition data, was used to propose a pharmacophore model for the PSMA active site.     

Aspidosperma (Apocynaceae) plant cytotoxicity and activity towards malaria parasites. Part II: experimental studies with Aspidosperma ramiflorum in vivo and in vitro

Several species of Aspidosperma plants are used to treat diseases in the tropics, including Aspidosperma ramiflorum, which acts against leishmaniasis, an activity that is experimentally confirmed. The species, known as guatambu-yellow, yellow peroba, coffee-peroba andmatiambu, grows in the Atlantic Forest of Brazil in the South to the Southeast regions. Through a guided biofractionation of A. ramiflorum extracts, the plant activity against Plasmodium falciparum was evaluated in vitro for toxicity towards human hepatoma G2 cells, normal monkey kidney cells and nonimmortalised human monocytes isolated from peripheral blood. Six of the seven extracts tested were active at low doses (half-maximal drug inhibitory concentration < 3.8 µg/mL); the aqueous extract was inactive. Overall, the plant extracts and the purified compounds displayed low toxicity in vitro. A nonsoluble extract fraction and one purified alkaloid isositsirikine (compound 5) displayed high selectivity indexes (SI) (= 56 and 113, respectively), whereas compounds 2 and 3 were toxic (SI < 10). The structure, activity and low toxicity of isositsirikine in vitro are described here for the first time in A. ramiflorum, but only the neutral and precipitate plant fractions were tested for activity, which caused up to 53% parasitaemia inhibition of Plasmodium berghei in mice with blood-induced malaria. This plant species is likely to be useful in the further development of an antimalarial drug, but its pharmacological evaluation is still required.     

Geographic variation in cardiovascular inflammation among healthy women in the Women's Health Study

Background

Geographic variation in traditional cardiovascular disease (CVD) risk factors has been observed among women in the US. It is not known whether state-level variation in cardiovascular inflammation exists or could be explained by traditional clinical risk factors and behavioral lifestyle factors.

Methods and Results

We used multilevel linear regression to estimate state-level variation in inflammatory biomarker patterns adjusted for clinical and lifestyle characteristics among 26,029 women free of CVD. Participants derived from the Women''s Health Study, a national cohort of healthy middle-aged and older women. Inflammatory biomarker patterns (plasma levels of high-sensitivity C-reactive protein (hsCRP), soluble intercellular adhesion molecule-1 (sICAM-1), and fibrinogen) were compared to state-level patterns of traditional CVD risk factors and global risk scores. We found that all three inflammatory biomarkers exhibited significant state-level variation including hsCRP (lowest vs. highest state median 1.3 mg/L vs. 2.7 mg/L, unadjusted random effect estimate 1^st to 99^th percentile range for log hsCRP 0.52, p<.001), sICAM-1 (325 ng/ml vs. 366ng/ml, unadjusted random effect estimate 1^st to 99^th percentile range 0.44, p<.001), and fibrinogen (322 mg/dL vs. 367 mg/dL, unadjusted random effect estimate 1^st to 99^th percentile range 0.41, p = .001). Neither demographic, clinical or lifestyle characteristics explained away state-level effects in biomarker patterns. Southern and Appalachian states (Arkansas, West Virginia) had the highest inflammatory biomarker values. Regional geographic patterns of traditional CVD risk factors and risk scores did not completely overlap with biomarkers of inflammation.

Conclusions

There is state-level geographic variation in inflammatory biomarkers among otherwise healthy women that cannot be completely attributed to traditional clinical risk factors or lifestyle characteristics. Future research should aim to identify additional factors that may explain geographic variation in biomarkers of inflammation among healthy women.     

Genetic dissection of Al tolerance QTLs in the maize genome by high density SNP scan

Background

Aluminum (Al) toxicity is an important limitation to food security in tropical and subtropical regions. High Al saturation on acid soils limits root development, reducing water and nutrient uptake. In addition to naturally occurring acid soils, agricultural practices may decrease soil pH, leading to yield losses due to Al toxicity. Elucidating the genetic and molecular mechanisms underlying maize Al tolerance is expected to accelerate the development of Al-tolerant cultivars.

Results

Five genomic regions were significantly associated with Al tolerance, using 54,455 SNP markers in a recombinant inbred line population derived from Cateto Al237. Candidate genes co-localized with Al tolerance QTLs were further investigated. Near-isogenic lines (NILs) developed for ZmMATE2 were as Al-sensitive as the recurrent line, indicating that this candidate gene was not responsible for the Al tolerance QTL on chromosome 5, qALT5. However, ZmNrat1, a maize homolog to OsNrat1, which encodes an Al³⁺ specific transporter previously implicated in rice Al tolerance, was mapped at ~40 Mbp from qALT5. We demonstrate for the first time that ZmNrat1 is preferentially expressed in maize root tips and is up-regulated by Al, similarly to OsNrat1 in rice, suggesting a role of this gene in maize Al tolerance. The strongest-effect QTL was mapped on chromosome 6 (qALT6), within a 0.5 Mbp region where three copies of the Al tolerance gene, ZmMATE1, were found in tandem configuration. qALT6 was shown to increase Al tolerance in maize; the qALT6-NILs carrying three copies of ZmMATE1 exhibited a two-fold increase in Al tolerance, and higher expression of ZmMATE1 compared to the Al sensitive recurrent parent. Interestingly, a new source of Al tolerance via ZmMATE1 was identified in a Brazilian elite line that showed high expression of ZmMATE1 but carries a single copy of ZmMATE1.

Conclusions

High ZmMATE1 expression, controlled either by three copies of the target gene or by an unknown molecular mechanism, is responsible for Al tolerance mediated by qALT6. As Al tolerant alleles at qALT6 are rare in maize, marker-assisted introgression of this QTL is an important strategy to improve maize adaptation to acid soils worldwide.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2164-15-153) contains supplementary material, which is available to authorized users.     

Alpha Lipoic Acid Alleviates Oxidative Stress and Preserves Blood Brain Permeability in Rats with Subarachnoid Hemorrhage

The neuroprotective effect of alpha lipoic acid (ALA; 100 mg/kg, po), a dithiol antioxidant, on experimentally induced subarachnoid hemorrhage (SAH) was assessed in Wistar albino rats. Neurological examination scores recorded at the 48th h of SAH induction were increased in SAH groups, which were accompanied with significant increases in the formation of reactive oxygen species, DNA fragmentation ratios, malondialdehyde levels and myeloperoxidase activity, while significant decreases in the brain glutathione content and Na⁺, K⁺-ATPase activity were observed. On the other hand, ALA treatment reversed all these biochemical indices as well as SAH-induced histopathological alterations. Increased brain edema, impaired blood-brain-barrier permeability and neurological scores were also improved by ALA treatment. The results demonstrate that ALA exerts neuroprotective effects via the enhancement of endogenous antioxidant enzyme activity, the inhibition of neutrophil accumulation and free radical generation, suggesting a therapeutic potential in reducing secondary injury after SAH in patients.     

The Anabolic Androgenic Steroid Nandrolone Decanoate Disrupts Redox Homeostasis in Liver,Heart and Kidney of Male Wistar Rats

The abuse of anabolic androgenic steroids (AAS) may cause side effects in several tissues. Oxidative stress is linked to the pathophysiology of most of these alterations, being involved in fibrosis, cellular proliferation, tumorigenesis, amongst others. Thus, the aim of this study was to determine the impact of supraphysiological doses of nandrolone decanoate (DECA) on the redox balance of liver, heart and kidney. Wistar male rats were treated with intramuscular injections of vehicle or DECA (1 mg.100 g⁻¹ body weight) once a week for 8 weeks. The activity and mRNA levels of NADPH Oxidase (NOX), and the activity of catalase, glutathione peroxidase (GPx) and total superoxide dismutase (SOD), as well as the reduced thiol and carbonyl residue proteins, were measured in liver, heart and kidney. DECA treatment increased NOX activity in heart and liver, but NOX2 mRNA levels were only increased in heart. Liver catalase and SOD activities were decreased in the DECA-treated group, but only catalase activity was decreased in the kidney. No differences were detected in GPx activity. Thiol residues were decreased in the liver and kidney of treated animals in comparison to the control group, while carbonyl residues were increased in the kidney after the treatment. Taken together, our results show that chronically administered DECA is able to disrupt the cellular redox balance, leading to an oxidative stress state.