Redox imbalance induces remodeling of glucose metabolism in Rhipicephalus microplus embryonic cell line.

Carbohydrate metabolism not only functions in supplying cellular energy but also has an important role in maintaining physiological homeostasis and in preventing oxidative damage caused by reactive oxygen species. Previously, we showed that arthropod embryonic cell lines have high tolerance to H2O2 exposure. Here, we describe that Rhipicephalus microplus tick embryonic cell line (BME26) employs an adaptive glucose metabolism mechanism that confers tolerance to hydrogen peroxide at concentrations too high for other organisms. This adaptive mechanism sustained by glucose metabolism remodeling promotes cell survival and redox balance in BME26 cell line after millimolar H2O2 exposure. The present work shows that this tick cell line could tolerate high H2O2 concentrations by initiating a carbohydrate-related adaptive response. We demonstrate that gluconeogenesis was induced as a compensation strategy that involved, among other molecules, the metabolic enzymes NADP-ICDH, G6PDH, and PEPCK. We also found that this phenomenon was coupled to glycogen accumulation and glucose uptake, supporting the pentose phosphate pathway to sustain NADPH production and leading to cell survival and proliferation. Our findings suggest that the described response is not atypical, being also observed in cancer cells, which highlights the importance of this model to all proliferative cells. We propose that these results will be useful in generating basic biological information to support the development of new strategies for disease treatment and parasite control.

Virtual Reality Exposure Treatment in Phobias: a Systematic Review.

We compare the relative efficacy of virtual reality therapy exposure (VRET) versus in vivo therapy exposure among individuals suffering from phobias. A systematic search was completed up to 03 April 2020, using the following databases: ACM Digital Library, ResearchGate, IEEE, Science Direct, MIT PressJournals, Center for Direct Scientific Communication (CCSD) and Mary Ann Liebert Publishers. Five authors searched the databases using the following terms: Virtual Reality, Phobia, Mental health, Computing, Therapy, HMD, CAVE, Virtual ambient, in virtuo, Avoidance, Exposure, VRET, in vivo, Anxiety, Agoraphobia, Social Phobia, Stimuli, Cognitive-behaviour. All studies that evaluate the effect of in virtuo exposure towards phobia rehabilitation were selected. By reviewing the article, each author then applied the inclusion and exclusion criteria, and 30 articles were selected. Data extracted included the number of samples, amount of sessions, study variables that may affect the final outcome, therapy technology. The data provided was synthesized using a meta-analysis based on the results. The results demonstrated a positive outcome of Virtual Reality Exposure Treatment in the treatment of most phobias. In contrast, some of these treatments did not work for a few specific phobias in which the standard procedures were more effective. The findings suggest that for some specific phobias treatment, Virtual Reality Exposure Treatment does not reach the in vivo exposure level of immersion and presence. Further research is needed to perform studies with higher-dimension samples, since many papers report a low sample size and that is probably why many of them have inconclusive results.

Mannitol reduces nephron loss after warm renal ischemia in a porcine model.

BACKGROUND: Mannitol has been employed to ameliorate renal warm ischemia damage during partial nephrectomy, however, there is limited scientific evidence to support the use of mannitol during partial nephrectomy. The objective of the present study was to investigate the glomerular number after renal warm ischemia, with and without the use of mannitol in a Pig Model. METHODS: Twenty-four male pigs were assigned into three groups. Eight animals were allocated to the sham group that was subjected to laparoscopic dissection of the left renal hilum, without renal ischemia. Eight animals were allocated to the ischemia group that had the left renal hilum clamped for 30 min through laparoscopic access. Eight animals received mannitol (250 mg/kg) before the occlusion of renal hilum for 30 min. The kidneys were collected after the euthanasia of the pigs 21 days post surgery. The right kidney was utilized as a self-control for each animal. Serum creatinine, urea levels, the weight and volume of the kidneys were measured. Glomerular volumetric density, volume-weighted glomerular volume, and cortical volume were quantified through stereological methods and employed to determine the number of nephrons per kidney. Student's t test and ANOVA were used for statistical analysis. RESULTS: In the ischemia group, the left kidney recorded a reduction of 24.6% (290, 000 glomeruli) in the number of glomeruli in comparison to the right kidney. Kidneys subjected to ischemia also displayed decreased weight and volume in comparison to the sham and mannitol groups. No difference was observed between the left and right kidneys from the sham and mannitol groups. Further, no distinction in serum creatinine and urea among the groups was observed. CONCLUSION: The use of mannitol significantly reduces nephron loss during warm ischemia in pigs.

Glomerular Morphology and Renal Function after Warm Ischemia by Main Artery or Selective Clamping in a Porcine Model.

OBJECTIVE: The study aimed to evaluate the ischemic and non-ischemic areas after selective arterial occlusion by using stereological analysis of glomeruli, and to compare them with main arterial clamping and sham-operated animals. MATERIALS AND METHODS: Twenty-four male pigs were used in the study. The animals were divided into 3 groups with 8 animals in each as follows: group sham, submitted to laparoscopic dissection of the renal pedicle but not submitted to ischemia; group arterial (A), submitted to left renal artery clamping; and group selective (S), submitted to left renal artery caudal branch occlusion. Groups A and S underwent 30 min of warm ischemia. Left and right kidneys were collected after 21 days and renal fragments were processed for stereological evaluation. Glomerular volume density (Vv[glom]), mean glomerular volume (MGV), and glomerular density were measured. Serum creatinine and urea were assessed preoperatively, 10 days after surgery, and before euthanasia. RESULTS: There was no significant difference among groups with regard to renal function. Renal weight and volume were similar among groups. Also, no difference was observed between the groups with regard to Vv[glom], MGV, and glomerular density, both when compared to its right control or when left kidneys were compared. CONCLUSIONS: Selective arterial clamping technique was neither superior nor inferior to main artery clamping.

Glycogen Synthase Kinase-3 is involved in glycogen metabolism control and embryogenesis of Rhodnius prolixus.

Rhodnius prolixus is a blood-feeding insect that transmits Trypanosoma cruzi and Trypanosoma rangeli to vertebrate hosts. Rhodnius prolixus is also a classical model in insect physiology, and the recent availability of R. prolixus genome has opened new avenues on triatomine research. Glycogen synthase kinase 3 (GSK-3) is classically described as a key enzyme involved in glycogen metabolism, also acting as a downstream component of the Wnt pathway during embryogenesis. GSK-3 has been shown to be highly conserved among several organisms, mainly in the catalytic domain region. Meanwhile, the role of GSK-3 during R. prolixus embryogenesis or glycogen metabolism has not been investigated. Here we show that chemical inhibition of GSK-3 by alsterpaullone, an ATP-competitive inhibitor of GSK3, does not affect adult survival rate, though it alters oviposition and egg hatching. Specific GSK-3 gene silencing by dsRNA injection in adult females showed a similar phenotype. Furthermore, bright field and 4'-6-diamidino-2-phenylindole (DAPI) staining analysis revealed that ovaries and eggs from dsGSK-3 injected females exhibited specific morphological defects. We also demonstrate that glycogen content was inversely related to activity and transcription levels of GSK-3 during embryogenesis. Lastly, after GSK-3 knockdown, we observed changes in the expression of the Wingless (Wnt) downstream target ß-catenin as well as in members of other pathways such as the receptor Notch. Taken together, our results show that GSK-3 regulation is essential for R. prolixus oogenesis and embryogenesis.

Non-classical gluconeogenesis-dependent glucose metabolism in Rhipicephalus microplus embryonic cell line BME26.

In this work we evaluated several genes involved in gluconeogenesis, glycolysis and glycogen metabolism, the major pathways for carbohydrate catabolism and anabolism, in the BME26 Rhipicephalus microplus embryonic cell line. Genetic and catalytic control of the genes and enzymes associated with these pathways are modulated by alterations in energy resource availability (primarily glucose). BME26 cells in media were investigated using three different glucose concentrations, and changes in the transcription levels of target genes in response to carbohydrate utilization were assessed. The results indicate that several genes, such as glycogen synthase (GS), glycogen synthase kinase 3 (GSK3), phosphoenolpyruvate carboxykinase (PEPCK), and glucose-6 phosphatase (GP) displayed mutual regulation in response to glucose treatment. Surprisingly, the transcription of gluconeogenic enzymes was found to increase alongside that of glycolytic enzymes, especially pyruvate kinase, with high glucose treatment. In addition, RNAi data from this study revealed that the transcription of gluconeogenic genes in BME26 cells is controlled by GSK-3. Collectively, these results improve our understanding of how glucose metabolism is regulated at the genetic level in tick cells.

The conserved role of the AKT/GSK3 axis in cell survival and glycogen metabolism in Rhipicephalus (Boophilus) microplus embryo tick cell line BME26.

BACKGROUND: Tick embryogenesis is a metabolically intensive process developed under tightly controlled conditions and whose components are poorly understood. METHODS: In order to characterize the role of AKT (protein kinase B) in glycogen metabolism and cell viability, glycogen determination, identification and cloning of an AKT from Rhipicephalus microplus were carried out, in parallel with experiments using RNA interference (RNAi) and chemical inhibition. RESULTS: A decrease in glycogen content was observed when AKT was chemically inhibited by 10-DEBC treatment, while GSK3 inhibition by alsterpaullone had an opposing effect. RmAKT ORF is 1584-bp long and encodes a polypeptide chain of 60.1 kDa. Phylogenetic and sequence analyses showed significant differences between vertebrate and tick AKTs. Either AKT or GSK3 knocked down cells showed a 70% reduction in target transcript levels, but decrease in AKT also reduced glycogen content, cell viability and altered cell membrane permeability. However, the GSK3 reduction promoted an increase in glycogen content. Additionally, either GSK3 inhibition or gene silencing had a protective effect on BME26 viability after exposure to ultraviolet radiation. R. microplus AKT and GSK3 were widely expressed during embryo development. Taken together, our data support an antagonistic role for AKT and GSK3, and strongly suggest that such a signaling axis is conserved in tick embryos, with AKT located upstream of GSK3. GENERAL SIGNIFICANCE: The AKT/GSK3 axis is conserved in tick in a way that integrates glycogen metabolism and cell survival, and exhibits phylogenic differences that could be important for the development of novel control methods.

Assessing the hydration free energy of a homologous series of polyols with classical and quantum mechanical solvation models.

Molecular dynamics (MD) simulations associated with the thermodynamic integration (TI) scheme and the polarizable continuum model (PCM) in combination with the SMD solvation model were used to study the hydration free energy of the homologous series of polyols, C(n)H(n+2)(OH)n (1 ≤ n ≤ 7). Both solvation models predict a nonlinear behavior for the hydration free energy with the increase of the number of hydroxyl groups. This study also indicates that there is a sizable solute polarization in aqueous solution and that the inclusion of the polarization effect is important for a reliable description of the free energy differences considered here.

Influence of conspecifics and road noise on the properties of the advertisement call of Phyllodytes luteolus (Anura, Hylidae).

Acoustic communication in animals can be affected by multiple biotic (intra and interspecific) and abiotic (e.g., wind and rain) natural noises. In addition, human beings produce additional novel sources of noise, which can reduce or inhibit the reception of acoustic signals by conspecifics, leading to behavioral changes. In this study, we investigated whether sound of conspecifics and road noise additively affect the acoustic parameters of the advertisement call of males of a Yellow Heart-tongued Frog (Phyllodytes luteolus). We hypothesized that males that vocalize in choruses (males calling nearby) and in areas close to highways (anthropic noise) will increase their temporal and spectral acoustic parameters, respectively, to avoid acoustic signal masking. We recorded the vocalizations of 38 males in environments close (N = 18) to and distant (N = 20) from highways in different social contexts (many or few individuals calling nearby). Contrary to our expectation, the results indicated that males calling in areas close to highways had lower dominant frequency calls than those from natural areas (far from highways), and that the density of males in the chorus had no influence on the acoustic parameters. Furthermore, we found a positive relationship between body size and intensity, indicating that larger individuals can emit calls that can reach greater distances. The advertisement call of Phyllodytes luteolus has a high dominant frequency, with little overlap with the frequency of anthropic noises (roads), which may explain its presence and reproductive success of this species in bromeliads from urbanized areas.

Endoscopic management of ureteral calculus in a patient with ureterosigmoidostomy diversion.

Lithiasis after urinary diversion is an uncommon condition that poses therapeutic challenges. The authors report the case of a patient submitted to cystectomy and ureterosigmoidostomy 35 years ago due to bladder endometriosis. The patient presented with a ureteral stone and was treated by retrograde endoscopic extraction.

Quantum biochemistry, molecular docking, and dynamics simulation revealed synthetic peptides induced conformational changes affecting the topology of the catalytic site of SARS-CoV-2 main protease.

The recent outbreak caused by SARS-CoV-2 continues to threat and take many lives all over the world. The lack of an efficient pharmacological treatments are serious problems to be faced by scientists and medical staffs worldwide. In this work, an in silico approach based on the combination of molecular docking, dynamics simulations, and quantum biochemistry revealed that the synthetic peptides RcAlb-PepI, PepGAT, and PepKAA, strongly interact with the main protease (Mpro) a pivotal protein for SARS-CoV-2 replication. Although not binding to the proteolytic site of SARS-CoV-2 Mpro, RcAlb-PepI, PepGAT, and PepKAA interact with other protein domain and allosterically altered the protease topology. Indeed, such peptide-SARS-CoV-2 Mpro complexes provoked dramatic alterations in the three-dimensional structure of Mpro leading to area and volume shrinkage of the proteolytic site, which could affect the protease activity and thus the virus replication. Based on these findings, it is suggested that RcAlb-PepI, PepGAT, and PepKAA could interfere with SARS-CoV-2 Mpro role in vivo. Also, unlike other antiviral drugs, these peptides have no toxicity to human cells. This pioneering in silico investigation opens up opportunity for further in vivo research on these peptides, towards discovering new drugs and entirely new perspectives to treat COVID-19.Communicated by Ramaswamy H. Sarma.

Comparative study between trimetazidine and ice slush hypothermia in protection against renal ischemia/reperfusion injury in a porcine model.

PURPOSE: The aim of the study was to compare the effects of renal ice slush hypothermia and the use of trimetazidine in the protection against ischemia/reperfusion (I/R) injury. MATERIALS AND METHODS: Fifteen farm pigs were submitted to left kidney ischemia and right nephrectomy during the same procedure. Animals were divided into three groups. Group 1 was submitted to warm ischemia; Group 2 was submitted to cold ischemia with ice slush; and Group 3 received trimetazidine 20 mg one day and 4 hours before surgery. Ischemia time was 120 minutes in all three groups. Serum creatinine (SCr) and plasma iohexol clearance (CLioh) were measured before surgery and on postoperative days (PODs) 1,3,7, and 14. Semi-quantitative analyses of histological alterations were performed by a pathologist. A p value of < 0.05 was considered significant. RESULTS: All groups showed elevation of serum creatinine in the first week. Serum creatinine was higher in Group 3 in the first and third postoperative days (Mean Cr: 5.5 and 8.1 respectively). Group 2 showed a lower increase in creatinine and a lower decrease in iohexol clearance than the others. Renal function stabilized in the fourteenth POD in all three groups. Analyses of histological alterations did not reach statistical significance between groups. CONCLUSION: Trimetazidine did not show protection against renal I/R injury in comparison to warm ischemia or hypothermia in a porcine model submitted to 120 minutes of renal ischemia.

Aedes fluviatilis cell lines as new tools to study metabolic and immune interactions in mosquito-Wolbachia symbiosis.

In the present work, we established two novel embryonic cell lines from the mosquito Aedes fluviatilis containing or not the naturally occurring symbiont bacteria Wolbachia, which were called wAflu1 and Aflu2, respectively. We also obtained wAflu1 without Wolbachia after tetracycline treatment, named wAflu1.tet. Morphofunctional characterization was performed to help elucidate the symbiont-host interaction in the context of energy metabolism regulation and molecular mechanisms of the immune responses involved. The presence of Wolbachia pipientis improves energy performance in A. fluviatilis cells; it affects the regulation of key energy sources such as lipids, proteins, and carbohydrates, making the distribution of actin more peripheral and with extensions that come into contact with neighboring cells. Additionally, innate immunity mechanisms were activated, showing that the wAflu1 and wAflu1.tet cells are responsive after the stimulus using Gram negative bacteria. Therefore, this work confirms the natural, mutually co-regulating symbiotic relationship between W. pipientis and A. fluviatilis, modulating the host metabolism and immune pathway activation. The results presented here add important resources to the current knowledge of Wolbachia-arthropod interactions.

Germ band retraction as a landmark in glucose metabolism during Aedes aegypti embryogenesis.

BACKGROUND: The mosquito A. aegypti is vector of dengue and other viruses. New methods of vector control are needed and can be achieved by a better understanding of the life cycle of this insect. Embryogenesis is a part of A. aegypty life cycle that is poorly understood. In insects in general and in mosquitoes in particular energetic metabolism is well studied during oogenesis, when the oocyte exhibits fast growth, accumulating carbohydrates, lipids and proteins that will meet the regulatory and metabolic needs of the developing embryo. On the other hand, events related with energetic metabolism during A. aegypti embryogenesis are unknown. RESULTS: Glucose metabolism was investigated throughout Aedes aegypti (Diptera) embryonic development. Both cellular blastoderm formation (CBf, 5 h after egg laying - HAE) and germ band retraction (GBr, 24 HAE) may be considered landmarks regarding glucose 6-phosphate (G6P) destination. We observed high levels of glucose 6-phosphate dehydrogenase (G6PDH) activity at the very beginning of embryogenesis, which nevertheless decreased up to 5 HAE. This activity is correlated with the need for nucleotide precursors generated by the pentose phosphate pathway (PPP), of which G6PDH is the key enzyme. We suggest the synchronism of egg metabolism with carbohydrate distribution based on the decreasing levels of phosphoenolpyruvate carboxykinase (PEPCK) activity and on the elevation observed in protein content up to 24 HAE. Concomitantly, increasing levels of hexokinase (HK) and pyruvate kinase (PK) activity were observed, and PEPCK reached a peak around 48 HAE. Glycogen synthase kinase (GSK3) activity was also monitored and shown to be inversely correlated with glycogen distribution during embryogenesis. CONCLUSIONS: The results herein support the hypothesis that glucose metabolic fate changes according to developmental embryonic stages. Germ band retraction is a moment that was characterized as a landmark in glucose metabolism during Aedes aegypti embryogenesis. Furthermore, the results also suggest a role for GSK3 in glycogen balance/distribution during morphological modifications.

The hallmarks of GSK-3 in morphogenesis and embryonic development metabolism in arthropods.

Several research groups around the world have studied diverse aspects of energy metabolism in arthropod disease vectors, with the aim of discovering potential control targets. As in all oviparous organisms, arthropod embryonic development is characterized by the mobilization of maternally-derived metabolites for the formation of new tissues and organs. Glycogen synthase kinase-3 (GSK-3) is a serine-threonine kinase described as an important regulator of metabolism and development in a wide range of organisms. GSK-3 was first identified based on its action upon glycogen synthase, a central enzyme in glycogen biosynthesis. Currently, it is recognized as a key component of multiple cellular processes such as glucose metabolism, apoptosis, cell proliferation, transcription, cell migration, and immune response. The present review will describe the current knowledge on GSK-3 activation and its role in morphogenesis and embryonic metabolism in arthropods. Altogether, the information discussed here can spark new approaches and strategies for further studies, enhancing our understanding of these important arthropod vectors and strengthening the resources in the search for novel control methods.

Expression and activity of glycogen synthase kinase during vitellogenesis and embryogenesis of Rhipicephalus (Boophilus) microplus.

Glycogen synthase kinase 3 (GSK-3) is classically described as a key enzyme involved in glycogen metabolism in mammals. GSK-3 belongs to a highly conserved family of serine/threonine protein kinases, whose members are involved in hormonal regulation, nuclear signaling, and cell fate determination in higher eukaryotes. We have cloned and characterized the RmGSK-3 gene from Rhipicephalus (Boophilus) microplus tick embryos. DNA and protein sequence analysis depicted high similarity to the corresponding enzyme, from both vertebrate and invertebrate animals. In addition, the mRNA transcription profile identified during embryogenesis was analyzed. We observed that the RmGSK-3 mRNA rapidly decreases from the 1st to 3rd day of development, and increases from the 3rd to 15th day. After the 15th day of development, we observed a near 50% reduction in RmGSK-3 mRNA transcription in comparison to the 1st day. We detected the GSK-3beta isoform in egg homogenates throughout embryogenesis using Western blot analysis. RmGSK-3 mRNA was present in fat body, midgut and ovary from partially and fully engorged adult female ticks. The highest mRNA level was observed in ovaries from both developmental stages and in first-day eggs. Furthermore, RmGSK-3 activity correlated with glycogen content variation. Finally, kinase activity in egg homogenates was inhibited by the specific inhibitor, SB-216763. These data suggest that RmGSK-3beta may be involved in glycogen metabolism regulation during R. microplus embryogenesis.

TOR as a Regulatory Target in Rhipicephalus microplus Embryogenesis.

Embryogenesis is a metabolically intensive process carried out under tightly controlled conditions. The insulin signaling pathway regulates glucose homeostasis and is essential for reproduction in metazoan model species. Three key targets are part of this signaling pathway: protein kinase B (PKB, or AKT), glycogen synthase kinase 3 (GSK-3), and target of rapamycin (TOR). While the role of AKT and GSK-3 has been investigated during tick embryonic development, the role of TOR remains unknown. In this study, TOR and two other downstream effectors, namely S6 kinase (S6K) and eukaryotic translation initiation factor 4E-binding protein 1 (4E-BP1), were investigated in in vitro studies using the tick embryonic cell line BME26. First, we show that exogenous insulin can stimulate TOR transcription. Second, TOR chemical inhibition led to a decrease in BME26 cell viability, loss of membrane integrity, and downregulation of S6K and 4E-BP1 transcription. Conversely, treating BME26 cells with chemical inhibitors of AKT or GSK-3 did not affect S6K and 4E-BP1 transcription, showing that TOR is specifically required to activate its downstream targets. To address the role of TOR in tick reproduction, in vivo studies were performed. Analysis of relative transcription during different stages of tick embryonic development showed different levels of transcription for TOR, and a maternal deposition of S6K and 4E-BP1 transcripts. Injection of TOR double-stranded RNA (dsRNA) into partially fed females led to a slight delay in oviposition, an atypical egg external morphology, decreased vitellin content in eggs, and decreased larval hatching. Taken together, our data show that the TOR signaling pathway is important for tick reproduction, that TOR acts as a regulatory target in Rhipicephalus microplus embryogenesis and represents a promising target for the development of compounds for tick control.

Antioxidants as Renoprotective Agents for Ischemia during Partial Nephrectomy.

Small renal masses have been diagnosed increasingly in recent decades, allowing surgical treatment by partial nephrectomy. This treatment option is associated with better renal function preservation, in comparison with radical nephrectomy. However, for obtaining a bloodless field during surgery, occlusion of renal artery and veins is often required, which results in transitory ischemia. The renal ischemia-reperfusion injury is associated with increased reactive oxygen species production leading to renal tissue damage. Thus, the use of antioxidants has been advocated in the partial nephrectomy perioperative period. Several antioxidants were investigated in regard to renal ischemia-reperfusion injury. The present manuscript aims to present the literature on the most commonly studied antioxidants used during partial nephrectomy. The results of experimental and clinical studies using antioxidants during partial nephrectomy are reported. Further, alimentary sources of some antioxidants are presented, stimulating future studies focusing on perioperative antioxidant-rich diets.

Carbohydrate Metabolic Compensation Coupled to High Tolerance to Oxidative Stress in Ticks.

Reactive oxygen species (ROS) are natural byproducts of metabolism that have toxic effects well documented in mammals. In hematophagous arthropods, however, these processes are not largely understood. Here, we describe that Rhipicephalus microplus ticks and embryonic cell line (BME26) employ an adaptive metabolic compensation mechanism that confers tolerance to hydrogen peroxide (H2O2) at concentrations too high for others organisms. Tick survival and reproduction are not affected by H2O2 exposure, while BME26 cells morphology was only mildly altered by the treatment. Furthermore, H2O2-tolerant BME26 cells maintained their proliferative capacity unchanged. We evaluated several genes involved in gluconeogenesis, glycolysis, and pentose phosphate pathway, major pathways for carbohydrate catabolism and anabolism, describing a metabolic mechanism that explains such tolerance. Genetic and catalytic control of the genes and enzymes associated with these pathways are modulated by glucose uptake and energy resource availability. Transient increase in ROS levels, oxygen consumption, and ROS-scavenger enzymes, as well as decreased mitochondrial superoxide levels, were indicative of cell adaptation to high H2O2 exposure, and suggested a tolerance strategy developed by BME26 cells to cope with oxidative stress. Moreover, NADPH levels increased upon H2O2 challenge, and this phenomenon was sustained mainly by G6PDH activity. Interestingly, G6PDH knockdown in BME26 cells did not impair H2O2 tolerance, but generated an increase in NADP-ICDH transcription. In agreement with the hypothesis of a compensatory NADPH production in these cells, NADP-ICDH knockdown increased G6PDH relative transcript level. The present study unveils the first metabolic evidence of an adaptive mechanism to cope with high H2O2 exposure and maintain redox balance in ticks.