Metabolic Reprogramming of Klebsiella pneumoniae Exposed to Serum and Its Potential Implications in Host Immune System Evasion and Resistance.

The aim of this study was to identify, using proteomics, the molecular alterations caused by human serum exposure to Klebsiella pneumoniae ACH2. The analysis was performed under two different conditions, native serum from healthy donors and heat-inactivated serum (to inactivate the complement system), and at two different times, after 1 and 4 h of serum exposure. More than 1,000 bacterial proteins were identified at each time point. Enterobactin, a siderophore involved in iron uptake, and proteins involved in translation were upregulated at 1 h, while the chaperone ProQ and the glyoxylate cycle were identified after 4 h. Enzymes involved in the stress response were downregulated, and the SOD activity was validated using an enzymatic assay. In addition, an intricate metabolic adaptation was observed, with pyruvate and thiamine possibly involved in survival and virulence in the first hour of serum exposure. The addition of exogenous thiamine contributes to bacterial growth in human serum, corroborating this result. During 4 h of serum exposure, the glyoxylate cycle (GC) probably plays a central role, and the addition of exogenous succinate suppresses the GC, inducing a decrease in serum resistance. Therefore, serum exposure causes important changes in iron acquisition, the expression of virulence factors, and metabolic reprogramming, which could contribute to bacterial serum resistance.

Preconditioning by Moderate-Intensity Exercise Prevents Gentamicin-Induced Acute Kidney Injury.

A strict correlation among proximal tubule epithelial cell dysfunction, proteinuria, and modulation of the Renin-Angiotensin System and Kalikrein-Kinin System are crucial factors in the pathogenesis of Acute Kidney Injury (AKI). In this study, we investigated the potential protective effect of preconditioning by moderate-intensity aerobic exercise on gentamicin-induced AKI. Male Wistar rats were submitted to a moderate-intensity treadmill exercise protocol for 8 weeks, and then injected with 80 mg/kg/day s.c. gentamicin for 5 consecutive days. Four groups were generated: 1) NT+SAL (control); 2) NT+AKI (non-trained with AKI); 3) T+SAL (trained); and 4) T+AKI (trained with AKI). The NT+AKI group presented: 1) impairment in glomerular function parameters; 2) increased fractional excretion of Na + , K + , and water; 4) proteinuria and increased urinary γ-glutamyl transferase activity (a marker of tubular injury) accompanied by acute tubular necrosis; 5) an increased renal angiotensin-converting enzyme and bradykinin B1 receptor mRNA expression. Interestingly, the preconditioning by moderate-intensity aerobic exercise attenuated all alterations observed in gentamicin-induced AKI (T+AKI group). Taken together, our results show that the preconditioning by moderate-intensity aerobic exercise ameliorates the development of gentamicin-induced AKI. Our findings help to expand the current knowledge regarding the effect of physical exercise on kidneys during physiological and pathological conditions.

An Ixodes persulcatus Inhibitor of Plasmin and Thrombin Hinders Keratinocyte Migration, Blood Coagulation, and Endothelial Permeability.

The skin is the first host tissue that the tick mouthparts, tick saliva, and a tick-borne pathogen contact during feeding. Tick salivary glands have evolved a complex and sophisticated pharmacological arsenal, consisting of bioactive molecules, to assist blood feeding and pathogen transmission. In this work, persulcatin, a multifunctional molecule that targets keratinocyte function and hemostasis, was identified from Ixodes persulcatus female ticks. The recombinant persulcatin was expressed and purified and is a 25-kDa acidic protein with 2 Kunitz-type domains. Persulcatin is a classical tight-binding competitive inhibitor of proteases, targeting plasmin (Ki: 28 nM) and thrombin (Ki: 115 nM). It blocks plasmin generation on keratinocytes and inhibits their migration and matrix protein degradation; downregulates matrix metalloproteinase 2 and matrix metalloproteinase 9; and causes a delay in blood coagulation, endothelial cell activation, and thrombin-induced fibrinocoagulation. It interacts with exosite I of thrombin and reduces thrombin-induced endothelial cell permeability by inhibiting vascular endothelial-cadherin disruption. The multifaceted roles of persulcatin as an inhibitor and modulator within the plasminogen-plasmin system and thrombin not only unveil further insights into the intricate mechanisms governing wound healing but also provide a fresh perspective on the intricate interactions between ticks and their host organisms.

Metarhizium anisopliae E6 secretome reveals molecular players in host specificity and toxicity linked to cattle tick infection.

Although Metarhizium anisopliae is one of the most studied fungal biocontrol agents, its infection mechanism is far from being completely understood. Using multidimensional protein identification technology (MudPIT), we evaluated the differential secretome of M. anisopliae E6 induced by the host Rhipicephalus microplus cuticle. The proteomic result showed changes in the expression of 194 proteins after exposure to host cuticle, such as proteins involved in adhesion, penetration, stress and fungal defense. Further, we performed a comparative genomic distribution of differentially expressed proteins of the M. anisopliae secretome against another arthropod pathogen, using the Beauveria bassiana ARSEF2860 protein repertory. Among 47 analyzed protein families, thirty were overexpressed in the M. anisopliae E6 predicted genome compared to B. bassiana. An in vivo toxicity assay using a Galleria mellonella model confirmed that the M. anisopliae E6 secretome was more toxic in cattle tick infections compared to other secretomes, including B. bassiana with cattle ticks and M. anisopliae E6 with the insect Dysdereus peruvianus, which our proteomic results had also suggested. These results help explain molecular aspects associated with host infection specificity due to genetic differences and gene expression control at the protein level in arthropod-pathogenic fungi.

Differential proteomics of Zika virus (ZIKV) infection reveals molecular changes potentially involved in immune system evasion by a Brazilian strain of ZIKV.

Zika virus (ZIKV) is an arbovirus that was responsible for multiple outbreaks from 2007 to 2015. It has been linked to cases of microcephaly in Brazil in 2015, among other neurological disorders. Differences among strains might be the reason for different clinical outcomes of infection. To evaluate this hypothesis, we performed a comparative proteomic analysis of Vero cells infected with the African strain MR766 (ZIKVAFR) and the Brazilian strain 17 SM (ZIKVBR). A total of 550 proteins were identified as differentially expressed in ZIKVAFR- or ZIKVBR-infected cells compared to the control. The main findings included upregulation of immune system pathways (neutrophil degranulation and adaptive/innate immune system) and potential activation of immune-system-related pathways by ZIKVAFR (mTOR, JAK-STAT, NF-κB, and others) compared with the ZIKVBR/control. In addition, phagocytosis by macrophages and engulfment of leukocytes were activated in ZIKVAFR infection. An in vivo analysis using an immunocompetent C57BL/6N mouse model identified interstitial pneumonia with neutrophil infiltration in the lungs only in mice infected with ZIKVBR at 48 hours postinfection, with a significant amount of virus detected. Likewise, only animals infected with ZIKVBR had viral material in the cytoplasm of lung macrophages. These results suggest that activation of the immune system by ZIKVAFR infection may lead to faster viral clearance by immune cells.

The proteomic and particle composition of human platelet lysate for cell therapy products.

Following health agencies warning, the use of animal origin supplements should be avoided in biological products proposed as therapy in humans. Platelet lysate and several other growth factors sources are alternatives to replace fetal calf serum, the current gold standard in clinical-grade cell culture. However, the platelet supplement's content lacks data due to different production methods. The principle behind these products relays on the lysis of platelets that release several proteins, some of which are contained in heterogeneous granules and coordinate biological functions. This study aims to analyze the composition and reproducibility of a platelet lysate produced with a standardized method, by describing several batches' protein and particle content using proteomics and dynamic light scattering. Proteomics data revealed a diversified protein content, with some related to essential cellular processes such as proliferation, morphogenesis, differentiation, biosynthesis, adhesion, and metabolism. It also detected proteins responsible for activation and binding of transforming growth factor beta, hepatocyte growth factor, and insulin-like growth factor. Total protein, biochemical, and growth factors quantitative data showed consistent and reproducible values across batches. Novel data on two major particle populations is presented, with high dispersion level at 231 ± 96 d.nm and at 30 ± 8 d.nm, possibly being an important way of protein trafficking through the cellular microenvironment. This experimental and descriptive analysis aims to support the content definition and quality criteria of a cell supplement for clinical applications.

In vitro and in vivo anti-inflammatory and anticoagulant activities of Myrciaria plinioides D. Legrand ethanol leaf extract.

Myrciaria plinioides D. Legrand (Myrtaceae) is a native plant of Southern Brazil, which have potential in the food industry due to its edible fruits. Many plants belonging to this genus have been used for a variety of illnesses, including inflammatory disorders due to antioxidant properties. However, therapeutic uses of M. plinioides have been poorly studied. The aim of study was to assess the anti-inflammatory and anticoagulant activities of the ethanol leaf extract of M. plinioides. In M. plinioides extract-treated RAW 264.7 cells, assessments of cell viability, TNF-α release and p38 MAPK pathway-dependent protein expression were detected. In addition, rat paw edema models were used to analyze the anti-inflammatory effect of the extract. Macrophages cell line treated with M. plinioides extract showed a slight decrease in cell viability. In LPS-stimulated macrophages treated with different concentrations of the extract for 24 h, TNF-α release was inhibited, while modulation of p38 signaling pathway and inhibition of NF-κB p65 protein expression were dose-dependent. In rats, the extract inhibited the formation of paw edema, while an inhibitory effect on trypsin-like enzymes derived from mast cells was seen. Furthermore, the extract presented anticoagulant activity via extrinsic pathway, being able to block specifically factor Xa and thrombin. The study suggests that extract possess potent anti-inflammatory and anticoagulant effects. M. plinioides present great biological potential as a source for the development of anti-inflammatory and anticoagulant drugs. Additional studies can be proposed to better elucidate the mechanism by which M. plinioides exerts its effects.

Effect of Lonomia obliqua Venom on Human Neutrophils.

The significant incidence of deforestation in South America culminates in the contact of humans with typical forests species. Among these species, one may highlight Lonomia obliqua caterpillar, which, when touched by humans, can poison them through their bristles. Therefore, better acknowledging the mechanisms involved in envenomation caused by Lonomia obliqua caterpillar bristle extract (LOCBE) may contribute to further treatments. Recently, we demonstrated that LOCBE induces a pro-inflammatory profile in endothelial cells; thus, we decided to investigate the effects of LOCBE on human polymorphonuclear neutrophils (PMN), which are the first leukocytes that migrate to the inflammatory focus. Our results showed that treatment with LOCBE induced PMN chemotaxis together with alterations in actin cytoskeleton and focal adhesion kinase (FAK) activation, favoring migration. Concurrently, LOCBE induced PMN adhesion to matrix proteins, such as collagen IV, fibronectin, and fibrinogen. Moreover, we observed that LOCBE attenuated PMN apoptosis and increased reactive oxygen species (ROS) production together with nuclear factor kB (NF-κB) activation-a redox-sensitive transcription factor-as well as interleukin (IL)-1ß and IL-8 release. We call attention to the ROS-dependent effect of LOCBE on increased cell migration once an antioxidant treatment reverted it. In summary, we report that LOCBE activates PMN, inducing pro-inflammatory responses modulated by ROS.

Zika Virus Infection Associated with Autism Spectrum Disorder: A Case Report.

INTRODUCTION: The aim of this case was to investigate the association of the Zika virus infection in utero with the autism spectrum disorder (ASD) as clinical outcome that presented no congenital anomalies. METHODS: ASD was diagnosed in the second year of life by different child neurologists and confirmed by DSM-5 and ASQ. After that, an extensive clinical, epidemiological, and genetic evaluations were performed, with main known ASD causes ruled out. RESULTS: An extensive laboratorial search was done, with normal findings. SNP array identified no pathogenic variants. Normal neuroimaging and EEG findings were also obtained. ZIKV (Zika virus) IgG was positive, while IgM was negative. Other congenital infections were negative. The exome sequencing did not reveal any pathogenic variant in genes related to ASD. CONCLUSION: Accordingly, this report firstly associates ZIKV exposure to ASD.

COVID-19 impacts the expression of molecular markers associated with neuropsychiatric disorders.

Coronavirus disease 2019 (COVID-19) was initially characterized due to its impacts on the respiratory system; however, many recent studies have indicated that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) significantly affects the brain. COVID-19 can cause neurological complications, probably caused by the induction of a cytokine storm, since there is no evidence of neurotropism by SARS-CoV-2. In line with this, the COVID-19 outbreak could accelerate the progression or affect the clinical outcomes of neuropsychiatric conditions. Thus, we analyzed differential gene expression datasets for clinical samples of COVID-19 patients and identified 171 genes that are associated with the pathophysiology of the following neuropsychiatric disorders: alcohol dependence, autism, bipolar disorder, depression, panic disorder, schizophrenia, and sleep disorder. Several of the genes identified are associated with causing some of these conditions (classified as elite genes). Among these elite genes, 9 were found for schizophrenia, 6 for autism, 3 for depression/major depressive disorder, and 2 for alcohol dependence. The patients with the neuropsychiatric conditions associated with the genes identified may require special attention as COVID-19 can deteriorate or accelerate neurochemical dysfunctions, thereby aggravating clinical outcomes.

SARSCOVIDB-A New Platform for the Analysis of the Molecular Impact of SARS-CoV-2 Viral Infection.

The COVID-19 pandemic caused by the new coronavirus (SARS-CoV-2) has become a global emergency issue for public health. This threat has led to an acceleration in related research and, consequently, an unprecedented volume of clinical and experimental data that include changes in gene expression resulting from infection. The SARS-CoV-2 infection database (SARSCOVIDB: https://sarscovidb.org/) was created to mitigate the difficulties related to this scenario. The SARSCOVIDB is an online platform that aims to integrate all differential gene expression data, at messenger RNA and protein levels, helping to speed up analysis and research on the molecular impact of COVID-19. The database can be searched from different experimental perspectives and presents all related information from published data, such as viral strains, hosts, methodological approaches (proteomics or transcriptomics), genes/proteins, and samples (clinical or experimental). All information was taken from 24 articles related to analyses of differential gene expression out of 5,554 COVID-19/SARS-CoV-2-related articles published so far. The database features 12,535 genes whose expression has been identified as altered due to SARS-CoV-2 infection. Thus, the SARSCOVIDB is a new resource to support the health workers and the scientific community in understanding the pathogenesis and molecular impact caused by SARS-CoV-2.

Chymase inhibition: A key factor in the anti-inflammatory activity of ethanolic extracts and spilanthol isolated from Acmella oleracea.

ETHNOPHARMACOLOGICAL RELEVANCE: Acmella oleracea (L.) R. K. Jansen (Asteraceae), known as jambú in Brazil, is used in traditional medicine as analgesic and for inflammatory conditions, characterized by the presence of N-alkylamides, mainly spilanthol. This bioactive compound is responsible for the above-described pharmacological properties, including sialagogue and anesthetic. AIM OF THE STUDY: This study aimed to characterize the anti-inflammatory effects of A. oleracea leaves (AOEE-L) and flowers (AOEE-F) extracts, including an isolated alkylamide (spilanthol), using in vitro and in vivo models. The mechanism underlying this effect was also investigated. MATERIALS AND METHODS: Extracts were analyzed by HPLC-ESI-MS/MS in order to characterize the N-alkylamides content. AOEE-L, AOEE-F (25-100 µg/mL) and spilanthol (50-200 µM) were tested in vitro on VSMC after stimulation with hyperglycemic medium (25 mM glucose). Their effects over nitric oxide (NO) generation, chymase inhibition and expression, catalase (CAT), superoxide anion (SOD) radical activity were evaluated. After an acute administration of extracts (10-100 mg/mL) and spilanthol (6.2 mg/mL), the anti-inflammatory effects were evaluated by applying the formalin test in rats. Blood was collected to measure serum aminotransferases activities, NO activity, creatinine and urea. RESULTS: A number of distinct N-alkylamides were detected and quantified in AOEE-L and AOEE-F. Spilanthol was identified in both extracts and selected for experimental tests. Hyperglycemic stimulation in VSMC promoted the expression of inflammatory parameters, including chymase, NO, CAT and SOD activity and chymase expression, all of them attenuated by the presence of the extracts and spilanthol. The administration of extracts or spilanthol significantly inhibited edema formation, NO production and cell tissue infiltration in the formalin test, without causing kidney and liver toxicity. CONCLUSION: Taken together, these results provide evidence for the anti-inflammatory activity of leaves and flowers extracts of jambú associated distinctly with their chemical profile. The effects appear to be associated with the inhibition of chymase activity, suppression of the proinflammatory cytokine NO and antioxidant activities.

Antifungal activity of Allamanda polyantha seed extract and its iridoids promote morphological alterations in Cryptococcus spp.

Cryptococcosis, caused by Cryptococcus spp., is an invasive fungal infection of the central nervous system, associated with high mortality, affecting mainly immunocompromised patients. Due to the development of resistance to the current therapy, there is an urgent need for less toxic and more effective antifungal agents. In this study, we describe the antifungal activity against Cryptococcus spp. of an aqueous seed extract from Allamanda polyantha (ASEAP) and two iridoids, plumieride and plumieridine, isolated from this extract with an antifungal activity. The capsule formation and the morphological alterations were evaluated using fluorescent microscopy. The cytotoxic activity was also investigated. The minimal inhibitory concentration (MIC) values of ASEAP for Cryptococcus gattii were 70 and 36 µg/ml (for the R265 and R272 strains, respectively) and 563 µg/ml for Cryptococcus neoformans H99. ASEAP inhibited C. neoformans H99 capsule formation, an important virulence factor, and decreased the cell body size for both the C. gattii strains. H99 cells also presented morphological alterations, with defects in bud detachment and nuclear fragmentation. Plumieride and plumieridine presented higher MIC values than ASEAP, indicating that other compounds might contribute to antifungal activity and/or that combination of the compounds results in a higher antifungal activity.

ZIKAVID-Zika virus infection database: a new platform to analyze the molecular impact of Zika virus infection.

The recent outbreak of Zika virus (ZIKV) in Brazil and other countries globally demonstrated the relevance of ZIKV studies. During and after this outbreak, there was an intense increase in scientific production on ZIKV infections, especially toward alterations promoted by the infection and related to clinical outcomes. Considering this massive amount of new data, mainly thousands of genes and proteins whose expression is impacted by ZIKV infection, the ZIKA Virus Infection Database (ZIKAVID) was created. ZIKAVID is an online database that comprises all genes or proteins, and associated information, for which expression was experimentally measured and found to be altered after ZIKV infection. The database, available at https://zikavid.org, contains 16,984 entries of gene expression measurements from a total of 7348 genes. It allows users to easily perform searches for different experimental hosts (cell lines, tissues, and animal models), ZIKV strains (African, Asian, and Brazilian), and target molecules (messenger RNA [mRNA] and protein), among others, used in differential expression studies regarding ZIKV infection. In this way, the ZIKAVID will serve as an additional and important resource to improve the characterization of the molecular impact and pathogenesis associated with ZIKV infection.

Ovarian tissue vitrification is more efficient than slow freezing to preserve ovarian stem cells in CF-1 mice.

OBJECTIVE: The aim of this study was to investigate the efficacy of protocols for mice ovary cryopreservation to compare the differences in Mouse Vasa Homologue expression (a germline cell marker) and ovarian viability after vitrification or slow freezing. METHODS: Female CF1 mice aged 40-45 days were randomly divided into three groups: Control, vitrification or slow freezing. Their ovaries were surgically removed, rinsed in saline solution and cryopreserved. For vitrification, we used a commercial protocol and for slow freeze, we used 1.5 M ethylene glycol (EG) as cryoprotectant. After that, the ovaries were processed for histological an immunohistochemical analysis, and counting of primordial, primary, pre-antral and antral follicles. RESULTS: No significant difference was found in the proportion of high-quality primordial, primary and pre-antral follicles after thawing/warming in the slow freezing and vitrification groups. The immunohistochemistry for MVH antibody demonstrated that the slow freeze group had a higher number of unmarked cells (p=0.012), indicating a harmful effect on the MVH expression in the ovarian tissue, where the cell structure is complex. CONCLUSION: Although both protocols indicated similar results in the histological analysis of follicular counts, the vitrification protocol was significantly better to preserve ovarian stem cells, an immature germ cell population. These cells are able to self-renew having regeneration potential, and may be effective for the treatment of ovarian failure and consequently infertility.

Integrative proteomics and pharmacogenomics analysis of methylphenidate treatment response.

Transcriptomics and candidate gene/protein expression studies have indicated several biological processes modulated by methylphenidate (MPH), widely used in attention-deficit/hyperactivity disorder (ADHD) treatment. However, the lack of a differential proteomic profiling of MPH treatment limits the understanding of the most relevant mechanisms by which MPH exerts its pharmacological effects at the molecular level. Therefore, our aim is to investigate the MPH-induced proteomic alterations using an experimental design integrated with a pharmacogenomic analysis in a translational perspective. Proteomic analysis was performed using the cortices of Wistar-Kyoto rats, which were treated by gavage with MPH (2 mg/kg) or saline for two weeks (n = 6/group). After functional enrichment analysis of the differentially expressed proteins (DEP) in rats, the significant biological pathways were tested for association with MPH response in adults with ADHD (n = 189) using genome-wide data. Following MPH treatment in rats, 98 DEPs were found (P < 0.05 and FC < -1.0 or > 1.0). The functional enrichment analysis of the DEPs revealed 18 significant biological pathways (gene-sets) modulated by MPH, including some with recognized biological plausibility, such as those related to synaptic transmission. The pharmacogenomic analysis in the clinical sample evaluating these pathways revealed nominal associations for gene-sets related to neurotransmitter release and GABA transmission. Our results, which integrate proteomics and pharmacogenomics, revealed putative molecular effects of MPH on several biological processes, including oxidative stress, cellular respiration, and metabolism, and extended the results involving synaptic transmission pathways to a clinical sample. These findings shed light on the molecular signatures of MPH effects and possible biological sources of treatment response variability.

Proteomics of Rat Lungs Infected by Cryptococcus gattii Reveals a Potential Warburg-like Effect.

Cryptococcus gattii is the causative agent of cryptococcosis infection that can lead to pneumonia and meningitis in immunocompetent individuals. The molecular basis of the pathogenic process and impact on the host biochemistry are poorly understood and remain largely unknown. In this context, a comparative proteomic analysis was performed to investigate the response of the host during an infection caused by C. gattii. Lungs of experimentally infected rats were analyzed by shotgun proteomics to identify differentially expressed proteins induced by C. gattii clinical strain. The proteomic results were characterized using bioinformatic tools, and subsequently, the molecular findings were validated in cell culture and lungs of infected animals. A dramatic change was observed in protein expression triggered by C. gattii infection, especially related to energy metabolism. The main pathways affected include aerobic glycolysis cycle, TCA cycle, and pyrimidine and purine metabolism. Analyses in human lung fibroblast cells confirmed the altered metabolic status found in infected lungs. Thus, it is clear that C. gattii infection triggers important changes in energy metabolism leading to the activation of glycolysis and lactate accumulation in lung cells, culminating in a cancerlike metabolic status known as the Warburg effect. The results presented here provide important insights to better understand C. gattii molecular pathogenesis.

The G Allele of the rs12050217 Polymorphism in the BDKRB1 Gene Is Associated with Protection for Diabetic Retinopathy.

Purpose: The plasma kallikrein-kinin system is activated during vascular injury caused by diabetic retinopathy (DR), being involved in hyperpermeability and inflammation. Bradykinin B1 receptor (B1R) is expressed in human retina, and its levels are increased in murine models of diabetes. Experimental studies reveal that B1R antagonists ameliorate retinal injury caused by diabetes in rodents. Thus, the aim of this study was to investigate the association between the rs12050217A/G polymorphism in the BDKRB1 gene, the gene that codifies B1R, and DR in type 2 diabetes mellitus (T2DM) patients. Methods: We analyzed 636 T2DM patients and 443 non-diabetic subjects. T2DM patients were categorized by the presence of non-proliferative DR (NPDR, n = 267), proliferative DR (PDR, n = 197), and absence of DR (n = 172). The BDKRB1 rs12050217A/G polymorphism was genotyped by real-time PCR using TaqMan MGB probes. Results: The genotype frequencies of the BDKRB1 rs12050217A/G polymorphism are in Hardy-Weinberg equilibrium and did not differ between T2DM patients and non-diabetic subjects (P > 0.05). The presence of the genotypes containing the rs12050217 G allele was less frequent in patients with PDR when compared to patients with NPDR and without DR (32.0%, 41.9%, and 43.0%, P = 0.045, respectively). Interestingly, the presence of G allele was associated with ~40% protection for PDR, which was confirmed after correction for the presence of hypertension, ethnicity, age, HDL, and gender (odds ratio = 0.616, 95% confidence interval 0.385-0.986, P = 0.043). Conclusion: For the first time, we showed that BDKRB1 rs12050217 G allele is associated with protection for the advanced stage of DR in T2DM patients; however, further studies are needed to confirm this finding.

Renal and vascular effects of kallikrein inhibition in a model of Lonomia obliqua venom-induced acute kidney injury.

BACKGROUND: Lonomia obliqua venom is nephrotoxic and acute kidney injury (AKI) is the main cause of death among envenomed victims. Mechanism underlying L. obliqua-induced AKI involves renal hypoperfusion, inflammation, tubular necrosis and loss of glomerular filtration and tubular reabsorption capacities. In the present study, we aimed to investigate the contribution of kallikrein to the hemodynamic instability, inflammation and consequent renal and vascular impairment. METHODOLOGY/PRINCIPAL FINDINGS: Addition of L. obliqua venom to purified prekallikrein and human plasma in vitro or to vascular smooth muscle cells (VSMC) in culture, was able to generate kallikrein in a dose-dependent manner. Injected in rats, the venom induced AKI and increased kallikrein levels in plasma and kidney. Kallikrein inhibition by aprotinin prevented glomerular injury and the decrease in glomerular filtration rate, restoring fluid and electrolyte homeostasis. The mechanism underlying these effects was associated to lowering renal inflammation, with decrease in pro-inflammatory cytokines and matrix metalloproteinase expression, reduced tubular degeneration, and protection against oxidative stress. Supporting the key role of kallikrein, we demonstrated that aprotinin inhibited effects directly associated with vascular injury, such as the generation of intracellular reactive oxygen species (ROS) and migration of VSMC induced by L. obliqua venom or by diluted plasma obtained from envenomed rats. In addition, kallikrein inhibition also ameliorated venom-induced blood incoagulability and decreased kidney tissue factor expression. CONCLUSIONS/SIGNIFICANCE: These data indicated that kallikrein and consequently kinin release have a key role in kidney injury and vascular remodeling. Thus, blocking kallikrein may be a therapeutic alternative to control the progression of venom-induced AKI and vascular disturbances.