Disclosing Ribose-5-Phosphate Isomerase B Essentiality in Trypanosomatids.

Ribose-5-phosphate isomerase (RPI) belongs to the non-oxidative branch of the pentose phosphate pathway, catalysing the inter-conversion of D-ribose-5-phosphate and D-ribulose-5-phosphate. Trypanosomatids encode a type B RPI, whereas humans have a structurally unrelated type A, making RPIB worthy of exploration as a potential drug target. Null mutant generation in Leishmania infantum was only possible when an episomal copy of RPIB gene was provided, and the latter was retained both in vitro and in vivo in the absence of drug pressure. This suggests the gene is essential for parasite survival. Importantly, the inability to remove the second allele of RPIB gene in sKO mutants complemented with an episomal copy of RPIB carrying a mutation that abolishes isomerase activity suggests the essentiality is due to its metabolic function. In vitro, sKO promastigotes exhibited no defect in growth, metacyclogenesis or macrophage infection, however, an impairment in intracellular amastigotes' replication was observed. Additionally, mice infected with sKO mutants rescued by RPIB complementation had a reduced parasite burden in the liver. Likewise, Trypanosoma brucei is resistant to complete RPIB gene removal and mice infected with sKO mutants showed prolonged survival upon infection. Taken together our results genetically validate RPIB as a potential drug target in trypanosomatids.We would like to thank Professor Ana Tomás from the Institute for Molecular and Cell Biology, University of Porto, Portugal, for providing LimTXNPx antibody; Dr. Paul Michels from Université Catholique de Louvain, Belgium, for providing Tbenolase antibody; Professor Graham Coombs, Strathclyde University, Glasgow, for LmCS antibody; Professor Buddy Ullman, School of Medicine, Oregan Health and Science University, USA, for LdHGPRT antibody; Dr. Christine Clayton, Zentrum fur Molekulare Biologie der Universitat Heidelberg, Germany, for TbAldolase antibody. We would also like to thank Professor Jeremy Mottram, University of Glasgow, for pGL345HYG and Professor Marc Ouellette, Centre de Recherche en Infectiologie, of Laval University, Canada, for pSPαNEOα and pSPαBLASTα. We would also like to thank Dr. Jane MacDougall from Photeomix, France, for proofreading the English of the manuscript. The research leading to these results has received funding from the European Community’s Seventh Framework Programme under grant agreement No. 602773 (Project KINDRED).’ The COST Action CM1307: Targeted chemotherapy towards diseases caused by endoparasites has also contributed for this work. We would like to acknowledge Fundação para a Ciência e Tecnologia (FTC) for supporting Joana Faria (SFRH/BD/79712/2011) and Inês Loureiro (SFRH/BD/64528/2009). Inês Loureiro was also supported by the European Community’s Seventh Framework Programme (KINDRED-PR300102-BD). JT is an Investigator FCT funded by National funds through FCT and co-funded through European Social Fund within the Human Potential Operating Programme. Nuno Santarem and Pedro Cecílio are supported by fellowships from the European Community’s Seventh Framework Programme under grant agreements No. 602773 (Project KINDRED) and No. 603181 (Project MuLeVaClin), respectively

Ribose-5-phosphate isomerase A regulates hepatocarcinogenesis via PP2A and ERK signaling

[[abstract]]The deregulated nonoxidative pentose phosphate pathway (PPP) is known to promote oncogenesis, but the molecular mechanism remains unknown. Here, we report that human ribose-5-phosphate isomerase A (RPIA) plays a role in human hepatocellular carcinoma (HCC). A significant increase in RPIA expression was detected both in tumor biopsies of HCC patients and in a liver cancer tissue array. Importantly, the clinicopathological analysis indicated that RPIA mRNA levels were highly correlated with clinical stage, grade, tumor size, types, invasion and alpha-fetoprotein levels in the HCC patients. In addition, we demonstrated that the ability of RPIA to regulate cell proliferation and colony formation in different liver cancer cell lines required ERK signaling as well as the negative modulation of PP2A activity and that the effects of RPIA could be modulated by the addition of either a PP2A inhibitor or activator. Furthermore, the xenograft studies in nude mice revealed that the modulation of RPIA in liver cancer cells regulated tumor growth and that NIH3T3 cells overexpressing RPIA exhibited increased proliferation, enhanced colony formation, elevated levels of p-ERK1/2 and accelerated tumor growth. This study provides new insight into the molecular mechanisms by which RPIA overexpression can induce oncogenesis in HCC. Furthermore, it suggests that RPIA can be a good prognosis biomarker and a potential target for HCC therapy

Improving Nutrition Utilization and Meat Quality of Broiler Chickens Through Solid-State Fermentation of Agricultural By-Products by Aureobasidium Pullulans

ABSTRACT A 35 d trial was conducted to evaluate the effects of dietary supplementation of co-fermented agricultural by-products, soybean hulls and Pleurotus eryngii stalk residue (PESR), with Aureobasidium pullulans on nutrients digestibility and meat quality in broilers fed on conventional corn-soybean meal basal diet. A total of 400 1-d-old Ross broilers were allotted to 4 dietary treatments with 4 replicate pens (25 birds per pen). Birds were fed the corn-soybean meal diets supplemented with 0% (CON), 0.5% fermented soybean hulls (0.5% FSBH), 0.5% fermented soybean hulls partially replaced with PESR (0.5% FSHP) and 1.0% FSHP. The broilers fed on the diet that contained fermented products had higher total tract apparent digestibility for hemicellulose than those on CON (p<0.05). Meanwhile, the birds fed on 0.5% FSHP also showed the lightest duodenum and jejunum weight among all groups. Compared with the CON, the inclusion of 1.0% FSHP in the diet significantly decreased ammonia N concentration in cecum followed by 0.5% FSHP and subsequent 0.5% FSBH group. Dietary supplementation of fermented products significantly improved WHC and increased protein content in meat as compared with the CON. Moreover, the fat content in meat decreased in the broilers that received 0.5% FSBH and 1.0% FSHP. In conclusion, dietary supplementation of co-fermented agricultural by-products, PESR and soybean meal, could improve the digestibility of hemicellulose and decrease the cecal ammonia N concentration; moreover, the increased WHC and protein level as well as decreased fat content in meat suggested the promising utilization of these low-cost materials as broiler feed additives

Improving Nutrition Utilization and Meat Quality of Broiler Chickens Through Solid-State Fermentation of Agricultural By-Products by Aureobasidium Pullulans

<div><p>ABSTRACT A 35 d trial was conducted to evaluate the effects of dietary supplementation of co-fermented agricultural by-products, soybean hulls and Pleurotus eryngii stalk residue (PESR), with Aureobasidium pullulans on nutrients digestibility and meat quality in broilers fed on conventional corn-soybean meal basal diet. A total of 400 1-d-old Ross broilers were allotted to 4 dietary treatments with 4 replicate pens (25 birds per pen). Birds were fed the corn-soybean meal diets supplemented with 0% (CON), 0.5% fermented soybean hulls (0.5% FSBH), 0.5% fermented soybean hulls partially replaced with PESR (0.5% FSHP) and 1.0% FSHP. The broilers fed on the diet that contained fermented products had higher total tract apparent digestibility for hemicellulose than those on CON (p<0.05). Meanwhile, the birds fed on 0.5% FSHP also showed the lightest duodenum and jejunum weight among all groups. Compared with the CON, the inclusion of 1.0% FSHP in the diet significantly decreased ammonia N concentration in cecum followed by 0.5% FSHP and subsequent 0.5% FSBH group. Dietary supplementation of fermented products significantly improved WHC and increased protein content in meat as compared with the CON. Moreover, the fat content in meat decreased in the broilers that received 0.5% FSBH and 1.0% FSHP. In conclusion, dietary supplementation of co-fermented agricultural by-products, PESR and soybean meal, could improve the digestibility of hemicellulose and decrease the cecal ammonia N concentration; moreover, the increased WHC and protein level as well as decreased fat content in meat suggested the promising utilization of these low-cost materials as broiler feed additives.</p></div