Plant 22-nt siRNAs mediate translational repression and stress adaptation.

Small interfering RNAs (siRNAs) are essential for proper development and immunity in eukaryotes1. Plants produce siRNAs with lengths of 21, 22 or 24 nucleotides. The 21- and 24-nucleotide species mediate cleavage of messenger RNAs and DNA methylation2,3, respectively, but the biological functions of the 22-nucleotide siRNAs remain unknown. Here we report the identification and characterization of a group of endogenous 22-nucleotide siRNAs that are generated by the DICER-LIKE 2 (DCL2) protein in plants. When cytoplasmic RNA decay and DCL4 are deficient, the resulting massive accumulation of 22-nucleotide siRNAs causes pleiotropic growth disorders, including severe dwarfism, meristem defects and pigmentation. Notably, two genes that encode nitrate reductases-NIA1 and NIA2-produce nearly half of the 22-nucleotide siRNAs. Production of 22-nucleotide siRNAs triggers the amplification of gene silencing and induces translational repression both gene specifically and globally. Moreover, these 22-nucleotide siRNAs preferentially accumulate upon environmental stress, especially those siRNAs derived from NIA1/2, which act to restrain translation, inhibit plant growth and enhance stress responses. Thus, our research uncovers the unique properties of 22-nucleotide siRNAs, and reveals their importance in plant adaptation to environmental stresses.

Immunoproteasome inhibition prevents progression of castration-resistant prostate cancer.

BACKGROUND: Castration-resistant prostate cancer (CRPC) is refractory to hormone treatment. This study aims to explore the effect and underlying mechanisms of immunoproteasome inhibition, a novel immunotherapy, on the progression of CRPC. METHODS: The immunoproteasome subunit LMP7 was silenced by using gene knockout or inhibited by the epoxyketone inhibitor ONX 0914 in a mouse CRPC tumour graft model and in interferon-γ-pretreated human CRPC cell lines in vitro. RESULTS: CRPC tissues reveal a significant "tumour-elicited" Th17-type inflammatory response which induces immunoproteasome subunit expression. LMP7 deficiency in host mice or in CRPC tumour grafts had no effect on the "tumour-elicited" Th17-type inflammatory response and tumour progression. However, the selective LMP7 inhibitor ONX 0914 strongly suppressed the "tumour-elicited" Th17-type inflammatory response and CRPC tumour progression. Treatment of wild-type mice receiving LMP7-deficient CRPC tumour grafts with ONX 0914 further suggested that immunoproteasome inhibition prevents CRPC progression through suppressing IL-17-induced angiogenesis and epithelial-mesenchymal transition via inactivation of COX-2/VEGF-A signalling and ß-catenin/Snail signalling. Treatment of LMP7-deficient mice receiving wild-type CRPC tumour grafts with ONX 0914 and inhibition of LMP7 in PC3 and 22Rv.1 cells with ONX 0914 showed that immunoproteasome inhibition also prevents CRPC progression through inducing CRPC cell apoptosis via activation of the unfolded protein response. CONCLUSIONS: We define a critical role of the immunoproteasome in CRPC and propose immunoproteasome inhibition as a promising therapeutic approach to suppress CRPC progression.

The Regulation of Nitrate Reductases in Response to Abiotic Stress in Arabidopsis.

The two homologous genes, NIA1 and NIA2, encode nitrate reductases in Arabidopsis, which govern the reduction of nitrate to nitrite. This step is the rate-limiting step of the nitrate assimilation and utilization. Therefore, the regulation of NIA1 and NIA2 is important for plant development and growth. Although they are similar in sequence and structure, their regulations are different. Genetic analysis uncovers that NIA1, rather than NIA2, plays a predominant role in adopting to ABA stress. Although both long-term stress conditions can cause an improvement in NIA1 levels, a decrease in NIA1 levels under short-term treatments seems to be necessary for plants to switch from the growth status into the adopting status. Interestingly, the downregulation of the NR is distinct under different stress conditions. Under ABA treatment, the NR proteins are degraded via a 26S-proteasome dependent manner, while the transcriptional regulation is the main manner to rapidly reduce the NIA1 levels under nitrogen deficiency and NaCl stress conditions. These results indicate that under stress conditions, the regulation of NIA1 is complex, and it plays a key role in regulating the balance between growth and adaptation.

Multiple factors and features dictate the selective production of ct-siRNA in Arabidopsis.

Coding transcript-derived siRNAs (ct-siRNAs) produced from specific endogenous loci can suppress the translation of their source genes to balance plant growth and stress response. In this study, we generated Arabidopsis mutants with deficiencies in RNA decay and/or post-transcriptional gene silencing (PTGS) pathways and performed comparative sRNA-seq analysis, revealing that multiple RNA decay and PTGS factors impede the ct-siRNA selective production. Genes that produce ct-siRNAs often show increased or unchanged expression and typically have higher GC content in sequence composition. The growth and development of plants can perturb the dynamic accumulation of ct-siRNAs from different gene loci. Two nitrate reductase genes, NIA1 and NIA2, produce massive amounts of 22-nt ct-siRNAs and are highly expressed in a subtype of mesophyll cells where DCL2 exhibits higher expression relative to DCL4, suggesting a potential role of cell-specific expression of ct-siRNAs. Overall, our findings unveil the multifaceted factors and features involved in the selective production and regulation of ct-siRNAs and enrich our understanding of gene silencing process in plants.

Comprehensive Landscape of HOXA2, HOXA9, and HOXA10 as Potential Biomarkers for Predicting Progression and Prognosis in Prostate Cancer.

Prostate cancer (PCa) is recognized as a common malignancy in male patients. The homeobox A cluster (HOXA) family members have been confirmed to be implicated in the development of several types of tumors. However, the expression pattern and prognostic values of HOXA genes in PCa have not been investigated. In this study, we analyzed TCGA datasets and identified six HOXA family members which showed a dysregulated expression in PCa specimens compared with nontumor specimens. We also explored the potential mechanisms involved in the dysregulation of HOXA family members in PCa, and the results of Pearson's correlation revealed that most HOXA members were negatively related to the methylation degree. Moreover, we explored the prognostic values of HOXA family members and identified six survival-related HOXA members. Importantly, HOXA2, HOXA9, and HOXA10 were identified as critical PCa-related genes which were abnormally expressed in PCa and associated with clinical outcomes of PCa patients. Then, we explored the association between the above three genes and immune cell infiltration. We observed that the levels of HOXA2, HOXA9, and HOXA10 were associated with the levels of immune infiltration of several kinds of immune cells. Overall, our findings identified the potential values of the HOXA family for outcome prediction in PCa, which might facilitate personalized counselling and treatment in PCa.

Efficacy and safety of Prostate stereotactic body radiotherapy for metastatic castration-resistant prostate cancer: A prospective cohort study.

BACKGROUND: The efficacy and safety of prostate SBRT in men with mCRPC is unknown. MATERIALS AND METHODS: A prospective cohort study was conducted with 125 men diagnosed with mCRPC. All patients received ADT plus chemotherapy. Patients were randomly assigned to receive daily prostate SBRT (36-48 Gy in 6-8 fractions). Patients who did not receive SBRT served as controls. RESULTS: The primary endpoints were PFS and OS. After 89 months of total follow-up, the median PFS was 13.8 months in the SBRT group (n = 61) and 12.0 months in the control group (n = 64) (HR, 0.87; 95% CI, 0.61-1.24; P = 0.249). The OS was 25.7 months in the SBRT group and 23.8 months in the control group (HR, 0.93; 95% CI, 0.65-1.33; P = 0.230). A non-significant increase in the PSA response rate (50.8% vs. 43.7%) and time to PSA progression (8.3 months vs. 7.0 months) was observed in the SBRT group compared to the control group; however, the time to symptomatic progression was significantly prolonged in the SBRT group (11.3 months) compared to the control group (8.5 months) (HR, 0.76; 95% CI, 0.53-1.08; P = 0.019). There was an 11.5% incidence of radiation cystitis and radiation rectitis in the SBRT group, and the degree and incidence of hormone-related and chemotherapy-related adverse events were similar between the two groups. CONCLUSION: Adding prostate SBRT significantly prolonged the time to symptomatic progression and non-significantly prolonged PFS and OS among men with mCRPC compared to treatment with ADT plus chemotherapy alone.

Clinical Evidence for Regenerative Endodontic Procedures: Immediate versus Delayed Induction?

Clinicians face many challenges when treating immature permanent teeth in young patients. Immediate blood clot induction can be a successful option as described by some case reports. No experimental studies or clinical trials have addressed this question. We have designed a clinical trial in which we hypothesized that there is no difference in success between immediate or delayed induction protocols. After confirmation of pulpal necrosis, patients were randomized. In the delayed group, 15 teeth were treated following the American Association of Endodontists guidelines, and calcium hydroxide was used as the intracanal medication. In the immediate group, 13 teeth had a blood clot inducted at the first appointment. The teeth were evaluated after 1, 3, and 12 months. Three independent evaluators assessed the periapical healing. The Pearson chi-square test or the Fisher exact test was used to compare the success rates between the 2 groups. Currently, of the 25 recruited patients (28 teeth), 19 have completed their 12-month follow-up. The group with delayed induction had a 71% success rate, and the group with immediate induction had a 33% success rate. In most cases (79%), trauma was the etiology. All successful cases started at stage 9 of root development (Nolla), and the majority showed healing type 2. Determination of the stage of root formation and etiology are possible critical factors for any therapeutic decision. In summary, it is early to conclude or suggest any of the protocols. Clearly, much more data are needed before sample size requirements can be met.

Drinking behavior from high school to young adulthood: differences by college education.

BACKGROUND: Recent serious alcohol-related events have raised public awareness of the prevalence of at-risk alcohol use among college undergraduates, but heavy alcohol consumption during late adolescence and young adulthood is not limited to college students. Alcohol consumption typically peaks in young adulthood regardless of education level, and risks related to alcohol misuse are shared by young adults, regardless of their educational choices. Differences in alcohol risk between college-attending and non-college-attending young adults are generally small, and emphasize the need for research examining the drinking patterns of both of these groups. METHODS: To better understand patterns of at-risk alcohol use and its association with education, this study compared at-risk alcohol use from 12 grade to young adulthood (age 24) in a sample of never-married young adults. Three groups were formed based on completed education when the survey was administered in young adulthood: high school or less, postsecondary education without a four-year college degree, and completed college. RESULTS: Men who completed college experienced the greatest increase in at-risk drinking from grade 12 to young adulthood; however, their at-risk alcohol use did not differ markedly from men in the other education groups in young adulthood. Men who did not complete college had high levels of alcohol risk in 12 grade and maintained or increased those levels in young adulthood, demonstrating a pattern of prolonged risk. Women whose completed education was high school or less experienced the fewest increases in at-risk alcohol use. Education group differences were not explained by place of residence or employment status. CONCLUSIONS: These results emphasize the need to intervene early to prevent at-risk alcohol use, and emphasize that at-risk alcohol use is neither unique, nor necessarily the highest among individuals who complete college.