Early renal injury indicators can help evaluate renal injury in patients with chronic hepatitis B with long-term nucleos(t)ide therapy

BACKGROUND Patients with chronic hepatitis B(CHB)with long-term nucleos(t)ide therapy may experience renal insufficiency.Traditional renal function indicators,such as urine protein,serum urea nitrogen(BUN),and serum creatinine,are normal when early mild lesions occur.Therefore,more sensitive renal function indicators are needed.AIM To investigate the significance of early renal injury indicators in evaluating renal injury in patients with CHB with long-term nucleos(t)ide therapy.METHODS We collected the clinical data of 69 outpatients with CHB at Peking University First Hospital from March 2018 to January 2020 who had been treated with longterm nucleos(t)ide therapy and analyzed the results of early renal injury indicators.Continuous normal distribution data were analyzed by the t-test to determine the difference between two groups.Continuous non-normally distributed data were analyzed by the Mann-Whitney U-test between two groups.The Kruskal-Wallis H test was used to determine the differences among multiple groups.Enumeration data were analyzed by the chi-square test.The related factors of early renal injury indicators were analyzed by logistic regression analysis.RESULTS The average treatment duration with nucleos(t)ide analogs of the 69 patients with CHB was 99.7±28.7 mo.The cases of patients with elevated BUN and hypophosphatemia were 6(8.7%)and 13(18.8%),respectively;31(44.9%)patients had abnormal early renal injury indicators,including 9 patients with abnormal urine microalbumin,7 patients with abnormal urine immunoglobulin,6 patients with abnormal urine transferrin,and 19 patients with abnormalα1 microglobulin.There were no significant differences in the mean values of age,sex,BUN,estimated glomerular filtration rate(eGFR),serum uric acid,serum calcium,or serum phosphorus between the two groups of patients with and without early renal injury indicators.However,the mean levels of serum creatinine and urine creatinine,N-acetyl-β-D-glucosidase enzyme,α1 microglobulin,and urine immunoglobulin in the former group of patients were significantly higher than those in the latter group of patients(P<0.05).The incidence of early renal injury in patients with eGFR≥90,60-89,and 30-59 mL/(min·1.73 m2)was 36.4%(8/22),47.6%(20/42),and 60%(3/5),respectively.Logistic regression analysis results showed that gamma-glutamyl transpeptidase[odds ratio(OR)=1.05(1.008-1.093),P=0.020],direct bilirubin[OR=1.548(1.111-2.159),P=0.010],serum creatinine[OR=1.079(1.022-1.139),P=0.006],and age[OR=0.981(0.942-1.022),P=0.357]were independent predictors of early renal injury.CONCLUSION Patients with CHB treated with long-term nucleos(t)ide analog therapy had a high probability of early renal injury,and early renal injury indicators were highly sensitive and could be used to monitor early renal impairment.

Demethylase-assisted site-specific detection of N^(1)-methyladenosine in RNA

The dynamic RNA modifications have been viewed as new posttranscriptional regulator in modulating gene expression as well as in a broad range of physiological processes.N^(1)-methyladenosine(m^(1)A)is one of the most prevalent modifications existing in multiple types of RNAs.In-depth investigation of the functions of m^(1)A requires the site-specific assessment of m^(1)A stoichiometry in RNA.Herein,we established a demethylase-assisted method(DA-m^(1)A)for the site-specific detection and quantification of m^(1)A in RNA.N^(1)-methyl group in m^(1)A could result in the stalling of reverse transcription at m^(1)A site,thus producing the truncated cDNA.E.coli AlkB is a demethylase that can demethylate m^(1)A to produce adenine in RNA,thus generating full-length cDNA from AlkB-treated RNA.Evaluation of the produced amounts of full-length cDNA by quantitative real-time PCR can achieve the site-specific detection and quantification of m^(1)A in RNA.With the DA-m^(1)A method,we examined and successfully confirmed the previously well-characterized m^(1)A sites in various types of RNAs with low false positive rate.In addition,we found that the level of m^(1)A was significantly decreased at the bromodomain containing 2(BRD2)mRNA position 1674 and CST telomere replication complex component 1(CTC1)mRNA position 5643 in human hepatocellular carcinoma tissues.The results suggest that these two m^(1)A sites in mRNA may be involved in liver tumorigenesis.Taken together,the DA-m^(1)A method is simple and enables the rapid,cost-effective,and site-specific detection and quantification of m^(1)A in RNA,which provides a valuable tool to decipher the functions of m^(1)A in human diseases.

6-Thioguanine incorporates into RNA and induces adenosine-to-inosine editing in acute lymphoblastic leukemia cells

6-Thioguanine(6TG)is a widely used chemotherapeutic agent for the treatment of a variety of human diseases including acute lymphoblastic leukemia.After entry into cells,6TG is metabolically converted into 6-thioguanosine(^(S)G)nucleotide that can be incorporated into the genome during DNA replication.^(S)G in genomic DNA could induce cell death by triggering the post-replicative mismatch repair(MMR)pathway.Meanwhile,incorporation of 6TG into the Cp G sites could perturb the global DNA methylation and gene regulation.However,the effect of 6TG on RNA modifications is still unknown.Adenosine-toinosine(A-to-I)editing in RNA is one of the most common post-transcriptional modifications in mammals and there is growing evidence showing the significant alteration of A-to-I RNA editing in tumor tissues compared to normal tissues.In the current study,we examined the incorporation of 6TG into RNA and investigated its effect on A-to-I editing of bladder cancer-associated protein(BLCAP)transcript in acute lymphoblastic leukemia cells.The results demonstrated that ^(S)G could be incorporated into various RNA species,with m RNA having the most abundant ^(S)G.In addition,the results showed 6TG treatment elevated A-to-I editing in BLCAP transcript through upregulating adenosine deaminase 2 acting on RNA(ADAR2),which eventually contributes to the decreased cell viability.This study highlights a new mechanism of the cytotoxicity of 6TG in inducing cell death.