A case report of drug interaction between co-packaged nirmatrelvir-ritonavir and tacrolimus causing hyponatremia in a lung transplant recipient.

BACKGROUND: Coronavirus disease 2019 (COVID-19) infection in lung transplant recipients can be lethal owing to the use of immunosuppressants. Antiviral agents may be administered to these patients. Co-packaged nirmatrelvir-ritonavir is a new agent currently being used in combination. CASE PRESENTATION: In this report, we present a case of a 64-year-old woman, a lung transplant recipient, who experienced hyponatremia and showed a high serum tacrolimus concentration following the administration of the co-packaged nirmatrelvir-ritonavir combination. CONCLUSION: Although the nirmatrelvir-ritonavir and tacrolimus combination is not contraindicated, other treatment strategies should be considered first, if available, and the dose of tacrolimus should be reduced when using the nirmatrelvir-ritonavir combination. In cases where combination therapy is necessary, serum tacrolimus levels should be closely monitored in lung transplant recipients. Documentation of more such reports is important to identify drug interactions between nirmatrelvir-ritonavir and other agents, with the aim of preventing severe adverse effects.

Nirmatrelvir-ritonavir compared with other antiviral drugs for the treatment of COVID-19 patients: A systematic review and meta-analysis.

At present, there are some differences in the research results of nirmatrelvir-ritonavir compared with other antiviral drugs for the treatment of COVID-19 patients. We aimed to evaluate the efficacy and safety of nirmatrelvir-ritonavir compared with other antiviral drugs and the impact of different antiviral drugs on the short- and long-term effects of COVID-19. PubMed, Embase, CENTRAL (Cochrane Central Register of Controlled Trials), Web of Science, Google Scholar, and MedRxiv were searched to identify relevant studies from inception to March 30, 2023. We conducted a meta-analysis to estimate the effects of nirmatrelvir-ritonavir compared with other antiviral drugs for the treatment of COVID-19 patients and safety outcomes. The RoB1 and ROBINS-I were used to assess the bias risk of the included studies. Revman 5.4 software was used for meta-analysis (PROSPERO Code No: CRD42023397816). Twelve studies were included, including 30 588 COVID-19 patients, of whom 13 402 received nirmatrelvir-ritonavir. The meta-analysis results showed that the nirmatrelvir-ritonavir group had a lower proportion of patients than the control group in terms of long-term mortality (odds ratio [OR] = 0.29, 95% confidence interval [CI]: 0.13-0.66), hospitalization (OR = 0.44, 95% CI: 0.37-0.53, short term; OR = 0.52, 95% CI: 0.36-0.77, long term), and disease progression (OR = 0.56, 95% CI: 0.38-0.83, short term; OR = 0.60, 95% CI: 0.48-0.74, long term), and nirmatrelvir ritonavir showed little difference in safety compared to the control group. Nirmatrelvir-ritonavir can reduce the mortality and hospitalization of COVID-19 patients compared with other antiviral drugs. Further large-scale studies remain to validate these findings.

Melatonin improves behavioral parameters and oxidative stress in zebrafish submitted to a leucine-induced MSUD protocol.

Maple syrup urine disease (MSUD) is an inherited metabolic disorder caused by a deficiency in branched-chain alpha-ketoacid dehydrogenase complex (BCKAC). The treatment is a standard therapy based on a protein-restricted diet with low branched-chain amino acids (BCAA) content to reduce plasma levels and, consequently, the effects of accumulating their metabolites, mainly in the central nervous system. Although the benefits of dietary therapy for MSUD are undeniable, natural protein restriction may increase the risk of nutritional deficiencies, resulting in a low total antioxidant status that can predispose and contribute to oxidative stress. As MSUD is related to redox and energy imbalance, melatonin can be an important adjuvant treatment. Melatonin directly scavenges the hydroxy radical, peroxyl radical, nitrite anion, and singlet oxygen and indirectly induces antioxidant enzyme production. Therefore, this study assesses the role of melatonin treatment on oxidative stress in brain tissue and behavior parameters of zebrafish (Danio rerio) exposed to two concentrations of leucine-induced MSUD: leucine 2 mM and 5mM; and treated with 100 nM of melatonin. Oxidative stress was assessed through oxidative damage (TBARS, DCF, and sulfhydryl content) and antioxidant enzyme activity (SOD and CAT). Melatonin treatment improved redox imbalance with reduced TBARS levels, increased SOD activity, and normalized CAT activity to baseline. Behavior was analyzed with novel object recognition test. Animals exposed to leucine improved object recognition due to melatonin treatment. With the above, we can suggest that melatonin supplementation can protect neurologic oxidative stress, protecting leucine-induced behavior alterations such as memory impairment.

A multiple-metabolites model to predict preliminary renal injury induced by iodixanol based on UHPLC/Q-Orbitrap-MS and 1H-NMR.

BACKGROUND & AIMS: There are some problems, such as unclear pathological mechanism, delayed diagnosis, and inaccurate therapeutic target of Contrast-induced acute kidney injury (CI-AKI). It is significantly important to find biomarkers and therapeutic targets that can indicate renal injury in the early stage of CI-AKI. This study aims to establish a multiple-metabolites model to predict preliminary renal injury induced by iodixanol and explore its pathogenesis. METHODS: Both UHPLC/Q-Orbitrap-MS and 1H-NMR methods were applied for urine metabolomics studies on two independent cohorts who suffered from a preliminary renal injury caused by iodixanol, and the multivariate statistical analysis and random forest (RF) algorithm were used to process the related date. RESULTS: In the discovery cohort (n = 169), 6 metabolic markers (leucine, indole, 5-hydroxy-L-tryptophan, N-acetylvaline, hydroxyhexanoycarnine, and kynurenic acid) were obtained by the cross-validation between the RF and liquid chromatography-mass spectrometry (LC-MS). Secondly, the 6 differential metabolites were confirmed by comparison of standard substance and structural identification of 1H-NMR. Subsequently, the multiple-metabolites model composed of the 6 biomarkers was validated in a validation cohort (n = 165). CONCLUSIONS: The concentrations of leucine, indole, N-acetylvaline, 5-hydroxy-L-tryptophan, hydroxyhexanoycarnitine and kynurenic acid in urine were proven to be positively correlated with the degree of renal injury induced by iodixanol. The multiple-metabolites model based on these 6 biomarkers has a good predictive ability to predict early renal injury caused by iodixanol, provides treatment direction for injury intervention and a reference for reducing the incidence of clinical CI-AKI further.

Oral Nirmatrelvir for High-Risk, Nonhospitalized Adults with Covid-19.

BACKGROUND: Nirmatrelvir is an orally administered severe acute respiratory syndrome coronavirus 2 main protease (Mpro) inhibitor with potent pan-human-coronavirus activity in vitro. METHODS: We conducted a phase 2-3 double-blind, randomized, controlled trial in which symptomatic, unvaccinated, nonhospitalized adults at high risk for progression to severe coronavirus disease 2019 (Covid-19) were assigned in a 1:1 ratio to receive either 300 mg of nirmatrelvir plus 100 mg of ritonavir (a pharmacokinetic enhancer) or placebo every 12 hours for 5 days. Covid-19-related hospitalization or death from any cause through day 28, viral load, and safety were evaluated. RESULTS: A total of 2246 patients underwent randomization; 1120 patients received nirmatrelvir plus ritonavir (nirmatrelvir group) and 1126 received placebo (placebo group). In the planned interim analysis of patients treated within 3 days after symptom onset (modified intention-to treat population, comprising 774 of the 1361 patients in the full analysis population), the incidence of Covid-19-related hospitalization or death by day 28 was lower in the nirmatrelvir group than in the placebo group by 6.32 percentage points (95% confidence interval [CI], -9.04 to -3.59; P<0.001; relative risk reduction, 89.1%); the incidence was 0.77% (3 of 389 patients) in the nirmatrelvir group, with 0 deaths, as compared with 7.01% (27 of 385 patients) in the placebo group, with 7 deaths. Efficacy was maintained in the final analysis involving the 1379 patients in the modified intention-to-treat population, with a difference of -5.81 percentage points (95% CI, -7.78 to -3.84; P<0.001; relative risk reduction, 88.9%). All 13 deaths occurred in the placebo group. The viral load was lower with nirmatrelvir plus ritonavir than with placebo at day 5 of treatment, with an adjusted mean difference of -0.868 log10 copies per milliliter when treatment was initiated within 3 days after the onset of symptoms. The incidence of adverse events that emerged during the treatment period was similar in the two groups (any adverse event, 22.6% with nirmatrelvir plus ritonavir vs. 23.9% with placebo; serious adverse events, 1.6% vs. 6.6%; and adverse events leading to discontinuation of the drugs or placebo, 2.1% vs. 4.2%). Dysgeusia (5.6% vs. 0.3%) and diarrhea (3.1% vs. 1.6%) occurred more frequently with nirmatrelvir plus ritonavir than with placebo. CONCLUSIONS: Treatment of symptomatic Covid-19 with nirmatrelvir plus ritonavir resulted in a risk of progression to severe Covid-19 that was 89% lower than the risk with placebo, without evident safety concerns. (Supported by Pfizer; ClinicalTrials.gov number, NCT04960202.).

Anti-fibrotic effects of branched-chain amino acids on hepatic stellate cells.

BACKGROUND/AIMS: Patients with liver cirrhosis (LC) have low levels of branched-chain amino acids (BCAAs). There is accumulating evidence that BCAAs have anti- fibrotic effects in cirrhosis. This study is aimed to evaluate the effect of BCAAs on the function and phenotype of activated hepatic stellate cells (HSCs). METHODS: LX-2, an immortalized human stellate cell line, was used in in vitro experiments. LX-2 cells were exposed to transforming growth factor ß1 (TGF-ß1) and BCAAs or to valine, leucine, and isoleucine, which are components of BCAAs. Activation of the TGF-ß signaling pathway in LX-2 cells was observed using real-time quantitative polymerase chain reaction and Western blotting. RESULTS: The increased expression of snail family transcriptional repressor 1 (SNAI1) was observed in LX-2 cells activated by TGF-ß1. After BCAA treatment, its expression was significantly decreased at the mRNA level. The increased expression of Col1α1 and TIMP2 at the mRNA level and alpha smooth muscle actin at the protein level in activated LX-2 cells decreased after BCAA treatment. Among the BCAA components, leucine and valine significantly abrogated TGF-ß-induced activation of LX-2 cells. BCAA treatment led to the decreased phosphorylation of Smad2 and p38 proteins, which are markers for Smad and Smad-independent p38 mitogen-activated protein kinase signaling pathways, respectively. CONCLUSION: BCAA treatment can improve hepatic fibrosis by directly affecting the activated state of hepatic stellate cells through inhibition of the TGF-ß signaling pathway. Among BCAA components, leucine and valine mainly abrogated TGF-ß-induced activation of HSCs. Our results suggest that BCAA may be used to attenuate the progression of liver fibrosis.

Preclinical characterization of an intravenous coronavirus 3CL protease inhibitor for the potential treatment of COVID19.

COVID-19 caused by the SARS-CoV-2 virus has become a global pandemic. 3CL protease is a virally encoded protein that is essential across a broad spectrum of coronaviruses with no close human analogs. PF-00835231, a 3CL protease inhibitor, has exhibited potent in vitro antiviral activity against SARS-CoV-2 as a single agent. Here we report, the design and characterization of a phosphate prodrug PF-07304814 to enable the delivery and projected sustained systemic exposure in human of PF-00835231 to inhibit coronavirus family 3CL protease activity with selectivity over human host protease targets. Furthermore, we show that PF-00835231 has additive/synergistic activity in combination with remdesivir. We present the ADME, safety, in vitro, and in vivo antiviral activity data that supports the clinical evaluation of PF-07304814 as a potential COVID-19 treatment.

MiT/TFE family members suppress L-leucyl-L-leucine methyl ester-induced cell death.

Lysosomes are degradative organelles essential for cell homeostasis. However, various internal and external stimuli, including L-leucyl-L-leucine methyl ester (LLOMe), which is one of the common lysosomotropic agents, permeabilize the lysosomal membrane, leading to lysosome-dependent cell death because of leakage of lysosomal contents to the cytosol. The microphthalmia/transcription factor E (MiT/TFE) family members, which include transcription factor EB (TFEB), transcription factor E3 (TFE3), and microphthalmia-associated transcription factor (MITF), are master regulators of lysosomal biogenesis and are known to be involved in the lysosomal stress response. However, their protective effects against cell death associated with lysosomal-membrane damage are still poorly understood. In this study, we confirmed that LLOMe-induced lysosomal damage triggered nuclear translocation of TFEB/TFE3/MITF and increased the mRNA levels of their target genes encoding lysosomal hydrolases and lysosomal membrane proteins in HeLa cells. Furthermore, we revealed that TFEB/TFE3/MITF knockdown exacerbated LLOMe-induced cell death. However, TFEB overexpression only slightly attenuated LLOMe-induced cell death, despite enhanced LLOMe-induced increase in CTSD mRNA levels, implying that the endogenous levels of MiT/TFE family members might be sufficient to promote lysosomal biogenesis in response to lysosomal-membrane damage. Our results suggest that MiT/TFE family members suppress the cell death associated with lysosomal-membrane damage.

Multicenter Study to Transplant Hepatitis C-Infected Kidneys (MYTHIC): An Open-Label Study of Combined Glecaprevir and Pibrentasvir to Treat Recipients of Transplanted Kidneys from Deceased Donors with Hepatitis C Virus Infection.

BACKGROUND: Single-center trials and retrospective case series have reported promising outcomes using kidneys from donors with hepatitis C virus (HCV) infection. However, multicenter trials are needed to determine if those findings are generalizable. METHODS: We conducted a prospective trial at seven centers to transplant 30 kidneys from deceased donors with HCV viremia into HCV-uninfected recipients, followed by 8 weeks of once-daily coformulated glecaprevir and pibrentasvir, targeted to start 3 days posttransplant. Key outcomes included sustained virologic response (undetectable HCV RNA 12 weeks after completing treatment with glecaprevir and pibrentasvir), adverse events, and allograft function. RESULTS: We screened 76 patients and enrolled 63 patients, of whom 30 underwent kidney transplantation from an HCV-viremic deceased donor (median kidney donor profile index, 53%) in May 2019 through October 2019. The median time between consent and transplantation of a kidney from an HCV-viremic donor was 6.3 weeks. All 30 recipients achieved a sustained virologic response. One recipient died of complications of sepsis 4 months after achieving a sustained virologic response. No severe adverse events in any patient were deemed likely related to HCV infection or treatment with glecaprevir and pibrentasvir. Three recipients developed acute cellular rejection, which was borderline in one case. Three recipients developed polyomavirus (BK) viremia near or >10,000 copies/ml that resolved after reduction of immunosuppression. All recipients had good allograft function, with a median creatinine of 1.2 mg/dl and median eGFR of 57 ml/min per 1.73 m2 at 6 months. CONCLUSIONS: Our multicenter trial demonstrated safety and efficacy of transplantation of 30 HCV-viremic kidneys into HCV-negative recipients, followed by early initiation of an 8-week regimen of glecaprevir and pibrentasvir.

Safety and tolerability of 6-month supplementation with a vitamin D, calcium and leucine-enriched whey protein medical nutrition drink in sarcopenic older adults.

AIMS: Safety and tolerability of prolonged supplementation with a vitamin D, calcium and leucine-enriched whey protein medical nutrition drink (WP-MND) was evaluated in sarcopenic older adults. METHODS: A 13-week double-blinded, randomized, isocaloric placebo-controlled trial (PROVIDE study; n = 380) was extended with a voluntary 13-week open-label extension (OLE). OLE participants were randomized to receive daily 1 or 2 servings of WP-MND (21 g protein, 3 g leucine, 10 µg vitD and 500 mg calcium per serving). Gastro-intestinal tolerability, kidney function and serum levels of calcidiol, parathyroid hormone (PTH) and calcium were evaluated at week 0, 13 and 26. RESULTS AND DISCUSSION: In response to the high daily protein intake (median1.5; IQR: 1.3, 1.7 g/kg BW/day), the estimated glomerular filtration rate (eGFR) increased in the test group during the RCT (p = 0.013). The same trend was observed for those participants with moderate chronic kidney disease. During OLE no eGFR change was observed in any of the groups. Serum calcidiol and calcium reached a plateau after 13-week WP-MND supplementation. As expected, PTH significantly changed in the opposite direction, decreasing during RCT in the test group (T vs C: p < 0.001) and during OLE in former control groups. During RCT, 20/366 participants with normal baseline calcidiol reached levels ≥ 100 nmol/L (T: n = 18; C: n = 2) and 6 developed albumin-corrected calcium levels > 2.55 mmol/L (T: n = 3; C: n = 3), without associated adverse events. CONCLUSION: A 6 months intervention with up to 2 servings of WP-MND did neither result in kidney function deterioration nor symptoms of vitamin D or calcium toxicity. The product was overall well tolerated.

Population Pharmacokinetics of Glecaprevir/Pibrentasvir in HCV-infected Japanese Subjects in Phase 3 CERTAIN-1 and CERTAIN-2 Trials.

Glecaprevir (GLE)/pibrentasvir (PIB) 300 mg/120 mg once daily (Mavyret/Maviret) is an all-oral, pangenotypic, interferon- and ribavirin-free combination regimen approved for the treatment of chronic hepatitis C virus (HCV) infection. The objective of the current analyses was to characterize the pharmacokinetics (PK) of GLE/PIB in HCV-infected Japanese patients. Data from 332 subjects enrolled in 2 Japan phase 3 trials, CERTAIN-1 and CERTAIN-2, were used in the analyses. Pharmacokinetics of GLE/PIB were characterized using a nonlinear mixed-effects modeling. The analyses evaluated the impact of covariates (concomitant medications and demographic and clinical covariates such as renal impairment, effect of cirrhotic status) on GLE/PIB PK. GLE and PIB PK were described by 1- and 2-compartment models, respectively. Presence of cirrhosis, age, and body weight were identified as significant covariates on GLE/PIB PK. A trend toward higher GLE and PIB exposures in older patients and higher PIB exposures in heavier patients was observed; however, these increases were not considered clinically meaningful. GLE and PIB exposures were higher in HCV-infected subjects with cirrhosis (Child-Pugh A; GLE area under the plasma concentration-time curve was 160% higher, and PIB area under the plasma concentration-time curve was 21% higher) compared to subjects without cirrhosis. Renal function (including subjects with end-stage renal disease with dialysis) had no impact on GLE or PIB exposures. The GLE/PIB dose was well tolerated in the Japanese population, and no dose adjustment is needed for the evaluated intrinsic and extrinsic factors.

Simplified monitoring for hepatitis C virus treatment with glecaprevir plus pibrentasvir, a randomised non-inferiority trial.

BACKGROUND & AIMS: Direct-acting antiviral (DAA) therapy for HCV has high efficacy and limited toxicity. We hypothesised that the efficacy of glecaprevir-pibrentasvir for chronic HCV with a simplified treatment monitoring schedule would be non-inferior to a standard treatment monitoring schedule. METHODS: In this open-label multicentre phase IIIb trial, treatment-naïve adults with chronic HCV without cirrhosis were randomly assigned (2:1) to receive glecaprevir-pibrentasvir 300 mg-120 mg daily for 8 weeks administered with a simplified or standard monitoring strategy. Clinic visits occurred at baseline and post-treatment week 12 in the simplified arm, and at baseline, week 4, week 8, and post-treatment week 12 in the standard arm. Study nurse phone contact occurred at week 4 and week 8 in both arms. Participants requiring adherence support were not eligible, including those reporting recent injecting drug use. The primary endpoint was sustained virological response at post-treatment week 12 (SVR12), with a non-inferiority margin of 6%. RESULTS: Overall, 380 participants (60% male, 47% genotype 1, 32% genotype 3) with chronic HCV were randomised and treated with glecaprevir-pibrentasvir in the simplified (n = 253) and standard (n = 127) arms. In the intention-to-treat population, SVR12 was 92% (95% CI 89%-95%) in the simplified and 95% (95% CI 92%-99%) in the standard arm (difference between arms -3.2%; 95% CI -8.2% to 1.8%) and did not reach non-inferiority. In the per-protocol population, SVR12 was 97% (95% CI 96%-99%) in the simplified and 98% (95% CI 96%-100%) in the standard arm. No treatment-related serious adverse events were reported. CONCLUSIONS: In patients with chronic HCV infection without cirrhosis, treatment with glecaprevir-pibrentasvir was safe and effective. In comparison to standard monitoring, a simplified monitoring schedule did not achieve non-inferiority. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT03117569. LAY SUMMARY: Direct-acting antiviral (DAA) therapy for hepatitis C is highly effective and well tolerated. The SMART-C randomised trial evaluated an 8-week regimen of glecaprevir-pibrentasvir for hepatitis C treatment, using a simplified monitoring schedule that included no pathology tests or clinic visits during treatment. This simplified strategy produced a high cure rate (92%), but this was not equivalent to the standard monitoring schedule cure rate (95%).

Glecaprevir/pibrentasvir for 8 weeks in treatment-naïve patients with chronic HCV genotypes 1-6 and compensated cirrhosis: The EXPEDITION-8 trial.

BACKGROUND & AIMS: Eight-week glecaprevir/pibrentasvir leads to high rates of sustained virological response at post-treatment week 12 (SVR12) across HCV genotypes (GT) 1-6 in treatment-naïve patients without cirrhosis. We evaluated glecaprevir/pibrentasvir once daily for 8 weeks in treatment-naïve patients with compensated cirrhosis. METHODS: EXPEDITION-8 was a single-arm, multicenter, phase IIIb trial. The primary and key secondary efficacy analyses were to compare the lower bound of the 95% CI of the SVR12 rate in i) patients with GT1,2,4-6 in the per protocol (PP) population, ii) patients with GT1,2,4-6 in the intention-to-treat (ITT) population, iii) patients with GT1-6 in the PP population, and iv) patients with GT1-6 in the ITT population, to pre-defined efficacy thresholds based on historical SVR12 rates for 12 weeks of glecaprevir/pibrentasvir in the same populations. Safety was also assessed. RESULTS: A total of 343 patients were enrolled. Most patients were male (63%), white (83%), and had GT1 (67%). The SVR12 rate in patients with GT1-6 was 99.7% (n/N = 334/335; 95%CI 98.3-99.9) in the PP population and 97.7% (n/N = 335/343; 95% CI 96.1-99.3) in the ITT population. All primary and key secondary efficacy analyses were achieved. One patient (GT3a) experienced relapse (0.3%) at post-treatment week 4. Common adverse events (≥5%) were fatigue (9%), pruritus (8%), headache (8%), and nausea (6%). Serious adverse events (none related) occurred in 2% of patients. No adverse event led to study drug discontinuation. Clinically significant laboratory abnormalities were infrequent. CONCLUSIONS: Eight-week glecaprevir/pibrentasvir was well tolerated and led to a similarly high SVR12 rate as the 12-week regimen in treatment-naïve patients with chronic HCV GT1-6 infection and compensated cirrhosis. TRIAL REGISTRATION: ClinicalTrials.gov, NCT03089944. LAY SUMMARY: This study was the first to evaluate an 8-week direct-acting antiviral (DAA) regimen active against all major types of hepatitis C virus (HCV) in untreated patients with compensated cirrhosis. High virological cure rates were achieved with glecaprevir/pibrentasvir across HCV genotypes 1-6, and these high cure rates did not depend on any patient or viral characteristics present before treatment. This may simplify care and allow non-specialist healthcare professionals to treat these patients, contributing to global efforts to eliminate HCV.

Effects of Leucine-Enriched Whey Protein Supplementation on Physical Function in Post-Hospitalized Older Adults Participating in 12-Weeks of Resistance Training Program: A Randomized Controlled Trial.

Age-related strength and muscle mass loss is further increased after acute periods of inactivity. To avoid this, resistance training has been proposed as an effective countermeasure, but the additional effect of a protein supplement is not so clear. The aim of this study was to examine the effect of a whey protein supplement enriched with leucine after resistance training on muscle mass and strength gains in a post-hospitalized elderly population. A total of 28 participants were included and allocated to either protein supplementation or placebo supplementation following resistance training for 12 weeks (2 days/week). Physical function (lower and upper body strength, aerobic capacity and the Short Physical Performance Battery (SPPB) test), mini nutritional assessment (MNA) and body composition (Dual X-ray Absorptiometry) were assessed at baseline and after 12 weeks of resistance training. Both groups showed improvements in physical function after the intervention (p < 0.01), but there were no further effects for the protein group (p > 0.05). Muscle mass did not improve after resistance training in either group (p > 0.05). In conclusion, 12 weeks of resistance training are enough to improve physical function in a post-hospitalized elderly population with no further benefits for the protein-supplemented group.

piRNA-DQ722010 contributes to prostate hyperplasia of the male offspring mice after the maternal exposed to microcystin-leucine arginine.

BACKGROUND: Microcystin-leucine arginine (MC-LR) could disrupt prostate development and cause prostate hyperplasia. But whether and how maternal and before-weaning MC-LR exposure causes prostate hyperplasia in male offspring by changing expression profile of P-element-induced wimpy (PIWI)-interacting RNAs (piRNAs) have not yet been reported. METHODS: From the 12th day in the embryonic period to the 21st day after offspring birth, three groups of pregnant mice that were randomly assigned were exposed to 0, 10, and 50 µg/L of MC-LR through drinking water followed by the analyses of their male offspring. Abortion rate and litter size of maternal mice were recorded. The prostate histopathology was observed. Differential expressed piRNAs of prostate were screened by piRNA microarray analysis. Murine prostate cancer cell line (RM-1) was used for further mechanism study. Luciferase report assay was used to determine the relationship between piRNA-DQ722010 and polypeptide 3 (Pik3r3). RESULTS: The downregulated expression of piRNA-DQ722010 was the most significant in piRNA microarray analysis in 10 µg/L MC-LR treated group, while Pik3r3 was significantly upregulated, consistent with the results that a distinct prostatic epithelial hyperplasia was observed and phosphoinositide-3-kinase (PI3K)/protien kinase B (AKT) signaling pathway was activated. Pik3r3 was verified as the target gene of piRNA-DQ722010. In addition, we found MC-LR decreased the expression of PIWI-like RNA-mediated gene silencing 2 (Piwil2) and 4 (Piwil4) both in vivo and in vitro, and both Piwil4 and Piwil2 could regulate the expression of DQ722010. CONCLUSION: MC-LR caused downregulation of piRNA-DQ722010 and PIWI proteins, while piRNA-DQ722010 downregulation promoted activation of PI3K/AKT signaling pathway inducing prostate hyperplasia by upregulating the expression of Pik3r3. In contrast, piRNA-DQ722010 downregulation may be attributed to PIWI proteins downregulation.