During normal development or during disease, animal cells experience hypoxic (low oxygen) conditions, and the hypoxia-inducible factor (HIF) transcription factors implement most of the critical changes in gene expression that enable animals to adapt to this stress. Here, we examine the roles of HIF-1 in post-mitotic aging. We examined the effects of HIF-1 over-expression and of hif-1 loss-of-function mutations on longevity in C. elegans, a powerful genetic system in which adult somatic cells are post-mitotic. We constructed transgenic lines that expressed varying levels of HIF-1 protein and discovered a positive correlation between HIF-1 expression levels and lifespan. The data further showed that HIF-1 acted in parallel to the SKN-1/NRF and DAF-16/FOXO transcription factors to promote longevity. HIF-1 over-expression also conferred increased resistance to heat and oxidative stress. We isolated and characterized additional hif-1 mutations, and we found that each of 3 loss-of-function mutations conferred increased longevity in normal lab culture conditions, but, unlike HIF-1 over-expression, a hif-1 deletion mutation did not extend the lifespan of daf-16 or skn-1 mutants. We conclude that HIF-1 over-expression and hif-1 loss-of-function mutations promote longevity by different pathways. These data establish HIF-1 as one of the key stress-responsive transcription factors that modulate longevity in C. elegans and advance our understanding of the regulatory networks that link oxygen homeostasis and aging.

C. elegans ahr-1 is orthologous to the mammalian aryl hydrocarbon receptor, and it functions as a transcription factor to regulate the development of certain neurons. Here, we describe the role of ahr-1 in a specific behavior: the aggregation of C. elegans on lawns of bacterial food. This behavior is modulated by nutritional cues and ambient oxygen levels, and aggregation is inhibited by the npr-1 G protein-coupled neuropeptide receptor gene. Loss-of-function mutations in ahr-1 or its transcription partner aha-1 (ARNT) suppress aggregation behavior in npr-1-deficient animals. This behavioral defect is not irreparable. Aggregation behavior can be restored to ahr-1-deficient animals by heat-shock induction of ahr-1 transcription several hours after ahr-1-expressing neurons have normally differentiated. We show that ahr-1 and aha-1 promote cell-type-specific expression of soluble guanylate cyclase genes that have key roles in aggregation behavior and hyperoxia avoidance. Aggregation behavior can be partially restored to ahr-1 mutant animals by expression of ahr-1 in only 4 neurons, including URXR and URXL. We conclude that the AHR-1:AHA-1 transcription complex regulates the expression of soluble guanylate cyclase genes and other unidentified genes that are essential for acute regulation of aggregation behavior.

BackgroundWith the development of assisted reproductive technology (ART) and its increasing success rate in the mainland of China, more attention has been paid to the safety of ART. In this study, we explored the associations between conception by ART and pregnancy/perinatal complications, and neonatal outcomes compared with similar outcomes following spontaneous conception.MethodsThis retrospective cohort study of pregnancies over a 3-year period (2013–2015) was performed at Beijing Obstetrics and Gynecology Hospital, Beijing, China. Subjects were divided into two groups: conception by ART (n = 2256) or spontaneous conception (n = 6768). According to different fertilization modes, the ART group was divided into in vitro fertilization (IVF, n = 1873) and intracytoplasmic sperm injection (ICSI, n = 383) subgroups. The ART group was also divided into two different embryo transfer methods; fresh embryo transfer (ET, n = 1583) and frozen embryo transfer (FET, n = 673) subgroups. Pregnancy complications, perinatal complications, and neonatal outcomes of the enrolled subjects were investigated and analyzed by univariate analysis and multivariate logistic regression.ResultsAfter adjustment for maternal age, gravidity, parity, maternal education, smoking, alcohol consumption, and body mass index (BMI), pregnancies conceived by ART were associated with a significantly increased incidence of gestational diabetes mellitus (GDM; OR 1.88, 95% CI 1.56–2.27), gestational hypertension (OR 2.18, 95% CI 1.83–2.60), and intrahepatic cholestasis of pregnancy (ICP) (OR 2.79, 95% CI 2.15–3.64), compared with spontaneous conception. These associations were similar for the singleton group. In the twin group, only the incidence of ICP was significantly higher than in controls. We found that pregnancies conceived by ART were associated with perinatal complications, including placental abruption (OR 2.14, 95% CI 1.33–3.45), premature rupture of membranes (PROM; OR 1.24, 95% CI 1.06–1.45), postpartum hemorrhage (OR 2.89, 95% CI 2.33–3.59) and polyhydramnios (OR 2.01, 95% CI 1.29–3.16). The singleton group had a similar result with placental abruption, but not with fetal membranes ruptures before labor and polyhydramnios. There were no significant differences in the incidence of these perinatal complications in the twin group. Some neonatal outcomes, including preterm labor (OR 4.29, 95% CI 3.84–4.80) and low birth weight (OR 1.72, 95% CI 1.42–2.08), were more likely to occur with singleton births after ART. However, there were no significant differences for these outcomes from twin pregnancies. Perinatal complications and neonatal outcomes were consistent between the IVF and ICSI subgroups. The FET and ET subgroups showed a similar increase in complications, except for the incidence of placental abruption. After taking into account the effects of parity, birth plurality and maternal age, the ART group still exhibited increased maternal and neonatal complications, although some differences narrowed or disappeared.ConclusionsThis retro...

The exonization of an Alu-like element into a coding sequence is unique to primates and this phenomenon distinguishes our genome from other mammals. Here, we report the presence of a special splicing variant of a proapoptotic protein Bcl-rambo in human lymph node, designated as Bcl-rambo beta. This variant contains a 98 bp Alu-like sequence which acts as an exon. There exists an in-frame stop codon within this inserted Alu-like cassette, resulting in generation of a premature protein of 104 amino acid residues. Unlike the Bcl-rambo, Bcl-rambo beta is lacking of the BH1, BH2 and BH3 motifs and becomes a BH4-only protein. Bcl-rambo beta is detected in several adult human tissues such as heart, lymph node and cervix but is absent in human brain tissue. In addition, Bcl-rambo beta is found not to be associated with mitochondria due to the absence of its C-terminal membrane anchor region. Nevertheless, this cytosol-localized protein is capable of promoting etoposideand Taxol-induced cell death. Although the exact function of the Alu sequence is not fully characterized, the Alu element within the Bcl-rambo beta appeared to contribute to the proapoptotic capability, since removing of the Alu sequence from Bcl-rambo beta abrogates its ability to induce cell death. Our data support the speculation that the Alu element insertion during the splicing process may play an important role in the generation of protein diversity in primate cells by a yet uncharacterized mechanism. ß

Checkpoint blockade therapy triggers tumor-specific immune responses in a variety of cancer types. We presumed that rectal cancer patients could have become sensitive to immunotherapy after receiving neoadjuvant chemoradiotherapy (nCRT). In this study, we report immune alternation in post-nCRT patients compared with pretreatment conditions from gene-expression omnibus (GEO) data. Whole-exome sequencing of 14 locally advanced rectal cancer (LARC) patient samples showed that nCRT induced new mutations compared with the paired pretreatment biopsies, evidenced by appearance of a neoantigen landscape. An association was identified between mutation burden and enrichment of immune activation-related pathways. Animal experiment results further demonstrated that radiotherapy enhanced the efficacy of anti-PD-1. Mutation burden and the neoantigens of LARC patients were associated with response to nCRT. The mRNA expression profiling of 66 pretreatment biopsy samples from LARC patients showed that immune activation-related pathways were enriched in response to nCRT. PD-L1 expression was negatively correlated with disease-free survival in the CD8low expression patient group who received nCRT in a cohort of 296 samples. Thus, nCRT was able to alter immune function in LARC patients, which may be associated with the appearance of neoantigens. Neoantigens could make rectal cancer patients potential candidates to receive checkpoint blockade immunotherapy, and mutation burden could be a useful biomarker to stratify patients into responding and nonresponding groups for immunotherapy.