Circular RNAs (circRNAs) are abundant and evolutionarily conserved RNAs of largely unknown function. Here, we show that a subset of circRNAs is translated in vivo. By performing ribosome footprinting ...from fly heads, we demonstrate that a group of circRNAs is associated with translating ribosomes. Many of these ribo-circRNAs use the start codon of the hosting mRNA, are bound by membrane-associated ribosomes, and have evolutionarily conserved termination codons. In addition, we found that a circRNA generated from the muscleblind locus encodes a protein, which we detected in fly head extracts by mass spectrometry. Next, by performing in vivo and in vitro translation assays, we show that UTRs of ribo-circRNAs (cUTRs) allow cap-independent translation. Moreover, we found that starvation and FOXO likely regulate the translation of a circMbl isoform. Altogether, our study provides strong evidence for translation of circRNAs, revealing the existence of an unexplored layer of gene activity.
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•Specific circRNAs are associated with translating ribosomes•Ribosome footprinting reads match termination codon signature for circMbl•circMbl3-derived protein is detected by mass spectrometry•circRNAs are translated in vitro and in vivo in a cap-independent manner
Pamudurti et al. show that a subset of circRNAs is translated. These circRNAs generally share the start codon with the hosting RNA, encode proteins with specific protein domains, and are translated in a cap-independent manner.
To clarify the allometric growth pattern and hunger tolerance of Hemibarbus maculatus Bleeker larvae, the morphological lengths of their functional organs were measured continuously and their primary ...feeding rates under a state of starvation were studied. A control group and starvation group were set up for this study, and 10 larvae were sampled from each group every day in order to study their allometric growth pattern and hunger tolerance. The results showed that the Hemibarbus maculatus larvae opened their mouths for feeding at 4 DAH (days after hatching), and the yolk sac disappeared completely at 11 DAH. The PNR (point of no return) of the Hemibarbus maculatus larvae was 12–13 DAH, and the ratio of the DAH in the mixed trophic period compared to the endotrophic period was 1.75, indicating that Hemibarbus maculatus larvae have strong starvation tolerance. Hemibarbus maculatus larvae preferentially developed their heads, fins, and eyes, related to the functions of feeding, balancing, and swimming, in order to cope with complex environments. Therefore, when considering a water temperature of 22.66 ± 1.56 °C, 4–5 DAH is the best time to cultivate in the pond, which should not be carried out later than 12 DAH. To clarify the allometric growth pattern and hunger tolerance of Hemibarbus maculatus Bleeker larvae, the morphological lengths of their functional organs were measured continuously and their primary feeding rates under a state of starvation were studied. A control group and starvation group were set up for this study, and 10 larvae were sampled from each group every day in order to study their allometric growth pattern and starvation tolerance. The results indicated that the Hemibarbus maculatus larvae opened their mouths for feeding at 4 days after hatching, and that the yolk sac disappeared completely at 11 days after hatching. The Hemibarbus maculatus larvae preferentially developed their heads, fins, and eyes, related to the functions of feeding, balancing, and swimming, in order to cope with complex environments. The growth inflection points for the head length, pectoral fin length, dorsal fin length, eye diameter, eye spacing, snout length, and body height were characterized by total lengths of 10.93 mm, 11.67 mm, 11.67 mm, 13.17 mm, 16.53 mm, 15.13 mm, and 15.13 mm, respectively. Prior to and following the inflection point, positive allometric growth was observed in all organs. After the inflection point, the dorsal fin continued to maintain positive allometric growth, while the others changed to isometric allometric growth. A growth inflection point was not observed for trunk length or the lengths of the tail and anal fins. The trunk length always maintained negative allometry, while the tail and anal fin lengths were reversed. The growth inflection point of the tail length was at a total length of 13.68 mm. Before and after the growth inflection point, negative and isometric allometric growths were observed, respectively. According to the relationship between the total length and number of days after hatching, the growth inflection point of the Hemibarbus maculatus larvae was concentrated at TL = 10.93–16.53 mm, which was observed 14–20 days after hatching. The point of no return for the Hemibarbus maculatus larvae was 12–13 days after hatching, and the ratio of days after hatching in the mixed trophic period to the endotrophic period was 1.75, indicating that the larvae had strong hunger tolerance. Therefore, when considering a water temperature of 22.66 ± 1.56 °C, 4–5 days after hatching is the best time to cultivate in the pond, and it should not be carried out later than 12 days after hatching.
Hypothalamic neurons that co-express agouti-related protein (AgRP), neuropeptide Y and γ-aminobutyric acid (GABA) are known to promote feeding and weight gain by integration of various nutritional, ...hormonal, and neuronal signals. Ablation of these neurons in mice leads to cessation of feeding that is accompanied by activation of Fos in most regions where they project. Previous experiments have indicated that the ensuing starvation is due to aberrant activation of the parabrachial nucleus (PBN) and it could be prevented by facilitating GABA(A) receptor signalling in the PBN within a critical adaptation period. We speculated that loss of GABA signalling from AgRP-expressing neurons (AgRP neurons) within the PBN results in unopposed excitation of the PBN, which in turn inhibits feeding. However, the source of the excitatory inputs to the PBN was unknown. Here we show that glutamatergic neurons in the nucleus tractus solitarius (NTS) and caudal serotonergic neurons control the excitability of PBN neurons and inhibit feeding. Blockade of serotonin (5-HT(3)) receptor signalling in the NTS by either the chronic administration of ondansetron or the genetic inactivation of Tph2 in caudal serotonergic neurons that project to the NTS protects against starvation when AgRP neurons are ablated. Likewise, genetic inactivation of glutamatergic signalling by the NTS onto N-methyl D-aspartate-type glutamate receptors in the PBN prevents starvation. We also show that suppressing glutamatergic output of the PBN reinstates normal appetite after AgRP neuron ablation, whereas it promotes weight gain without AgRP neuron ablation. Thus we identify the PBN as a hub that integrates signals from several brain regions to bidirectionally modulate feeding and body weight.
Autophagy is a conserved pathway that delivers cytoplasmic contents to the lysosome for degradation. Here we consider its roles in neuronal health and disease. We review evidence from mouse knockout ...studies demonstrating the normal functions of autophagy as a protective factor against neurodegeneration associated with intracytoplasmic aggregate-prone protein accumulation as well as other roles, including in neuronal stem cell differentiation. We then describe how autophagy may be affected in a range of neurodegenerative diseases. Finally, we describe how autophagy upregulation may be a therapeutic strategy in a wide range of neurodegenerative conditions and consider possible pathways and druggable targets that may be suitable for this objective.
In this review, Menzies et al. discuss the importance of autophagy function for brain health, outlining connections between autophagy dysfunction and neurodegenerative disorders. The potential for autophagy as a therapeutic strategy for neurodegenerative disease is discussed, along with how this may be achieved.
In order to determine whether the glucose-alanine cycle regulates rates of hepatic mitochondrial oxidation in humans, we applied positional isotopomer NMR tracer analysis (PINTA) to assess rates of ...hepatic mitochondrial oxidation and pyruvate carboxylase flux in healthy volunteers following both an overnight (12 hours) and a 60-hour fast. Following the 60-hour fast, rates of endogenous glucose production and mitochondrial oxidation decreased, whereas rates of hepatic pyruvate carboxylase flux remained unchanged. These reductions were associated with reduced rates of alanine turnover, assessed by 3-13Calanine, in a subgroup of participants under similar fasting conditions. In order to determine whether this reduction in alanine turnover was responsible for the reduced rates of hepatic mitochondrial oxidation, we infused unlabeled alanine into another subgroup of 60-hour fasted subjects to increase rates of alanine turnover, similar to what was measured after a 12-hour fast, and found that this perturbation increased rates of hepatic mitochondrial oxidation. Taken together, these studies demonstrate that 60 hours of starvation induce marked reductions in rates of hepatic mitochondrial oxidation, which in turn can be attributed to reduced rates of glucose-alanine cycling, and reveal a heretofore undescribed role for glucose-alanine in the regulation of hepatic mitochondrial oxidation in humans.
The ankyrin repeat domain 49 (ANKRD49) is an evolutionarily conserved protein highly expressed in testes. However, the function of ANKRD49 in spermatogenesis is unknown. In this study, we found that ...ANKRD49 resides primarily in nucleus of spermatogonia, spermatocytes and round spermatids. ANKRD49 overexpression augments starvation-induced autophagy in male germ GC-1 cells whereas shRNA knockdown of ANKRD49 attenuates the autophagy. Inhibition of NF-kappaB pathway by its inhibitors or p65 siRNA prevents the ANKRD49-dependent autophagy augmentation, demonstrating that ANKRD49 enhances autophagy via NF-kappaB pathway. Our findings suggest that ANKRD49 plays an important role in spermatogenesis via promotion of autophagy-dependent survival.
The aim of this article is to emphasize that starvation is an important potential consequence of psychosis and to provide recommendations for management of this condition. A review of the literature ...on food refusal and starvation in patients with psychotic illnesses was performed. Our search strategy returned 54 articles with one article meeting inclusion criteria. Additional independent research returned an additional four cases of patients with psychosis engaging in self-starvation. The cases of several patients from our institution who engaged in self-starvation behaviors as a result of psychosis are also presented. The management and outcomes of each of these 10 patients are discussed. Starvation secondary to psychosis is an important but underappreciated consequence of psychosis that can lead to serious adverse outcomes in these patients. Few cases have been reported in the literature. More study is warranted to develop evidence-based management guidelines.
Effective refeeding of emaciated horses requires strategic management, including knowledge of tissue specific contributions to metabolic processes. To determine the differences in metabolic activity ...among body condition score (BCS) groups, 8 horses donated to this study were evaluated for BCS (1–9 scale,1 = emaciated and 9 = obese); where horses with BCS lower than 3 were considered emaciated (n = 4), and those with a BCS between 4 and 6 were considered moderate (n = 4). All horses were humanely euthanized using sodium barbiturate overdose, and during necropsy, tissue samples across 4 types were collected: muscle (M: cardiac and skeletal), fat (F: mesenteric, neck crest, omental, and peritoneal), gastrointestinal tract (G: stomach, duodenum, jejunum, ileum, and cecum), and organs (O: liver, kidney, and spleen). Samples were placed in liquid nitrogen and stored at −80°C before isolating RNA for gene expression analysis. Relative gene expression (using 2^-DCt) of RPL32, GLUT4, CPT1, and PDK4 were measured across tissues and between F, G, O and M, using geometric mean of GAPDH and TUBA4A as reference genes. Class, tissue, and BCS effects on PCR data were analyzed using generalized linear mixed models with breed and individual animals as random block effects. Shapiro-Wilk and Levine's test were used to determinenormality, and ranked transformation applied where appropriate. Post hoc multiple comparisons were performed with Tukey's adjustment and significance was identified at P < 0.05 (SAS 9.4, Cary, NC). No differences were detected between BCS groups (P > 0.05). Tissue classification had a significant effect on each target gene expression, where CPT 1 had lower expression in O 0.170 (0.440), 2^-DCt median (interquartile range), P < 0.001 than F 0.100 (0.125) and M 0.06 (0.150), P < 0.0001). No differences were detected for tissue classification for GLUT4, PDK4 or RPL32 (P > 0.05). Further, no individual tissue, BCS, or interactions were identified across all tissue type and gene pairs (P > 0.05). Despite known physiologic and physical differences in emaciated versus moderate BCS equids, gene expression was relatively unaffected in this study, which may be due to the tightly controlled nature of each gene to maintaining life. Knowledge of gene activity in the horse, and especially across tissue profiles and in the presence of sodium barbiturate is limited within the existing literature. Further investigation into tissue-specific differences may aid in understanding metabolic changes associated with BCS and should be evaluated in the presence and absence of euthanasia solution to fully elicit potential effects.
Starved horses with low body condition scores (BCS, < 3 out of 9) continues to be a prominent welfare concern, yet limited nutritional studies on the reconditioning process exist. The aim of this ...study was to determine how alternative diets affected blood chemistry panels and body composition in mature, starved (initial BCS 1 or 2) light breed horses during the refeeding process (final BCS 4, UTK IACUC 2811–1220). Horses (n = 10, 18.8 ± 2.5 y (mean ± SD), BCS 1.4 ± 0.5, 3 geldings and 6 mares, light breeds) were placed on a control diet (C; 100% digestible energy, DE, from grass hay and Purina Free Balance) or a concentrate diet (S; 50 % DE from grass hay and 50% DE from Purina Equine Senior). Diets were formulated to increase caloric intake in accordance with previously established refeeding recommendations and the NRC (2007), where horses were increased from 50% DE to 100% DE over 10 d to prevent refeeding syndrome, and then were increased up to 145% DE as needed based on weekly body weight (BW) until a BCS of 4 was reached. Weekly BW and BCS were assessed by 3 independent reviewers and plasma samples collected at each BCS increase based on reviewer average and an increase in of 16–20 kg in BW. Diet and BCS effects on blood chemistry and body composition were analyzed using generalized linear mixed models in SAS, with breed and individual animals as random effects, and mean separation using Tukey's adjustment.Significance was detected at P < 0.05 (SAS 9.4, Cary, NC). Non-normally distributed data were rank transformed as determined by Shapiro-Wilk. Of the 10 horses in the study, 3 were euthanized within 10d of enrollment due to infectious disease or colic unassociated with dietary treatment, 1 was disenrolled due to pneumonia, and the remaining 6 horses were fully reconditioned (C: n = 3, S: n = 3). Horses were recovered similarly between diet groups (change in BW: C = 46.15 ± 9.9 kg, S = 41.8 ± 14.9 kg, mean ± SD, P > 0.05). Plasma creatine kinase differed by BCS (P = 0.0007), whereas creatinine differed by both diet (P = 0.006) and BCS (P < 0.0001); however, all values were within normal limits. Lactose was lower in BCS 4 horses compared with all other scores, yet all values were also within normal ranges (P = 0.0007). Rib fat thickness was greater in BCS 4 horses (C = 0.35(0.08)mm, S = 0.38(0.20)mm, median(IQR)) than all other BCS (P = 0.001). Rump fat thickness was highest in BCS 4 horses (S = 0.36 (0.13), C = 0.30 (0.05)). Based on our findings, grass hay and complete feed concentrates can be used to successfully recover emaciated horses. Further studies would be helpful in determining optimal refeeding protocols.
We conducted a phenotypic, transcriptional, metabolic, and genetic analysis of quiescence in yeast induced by starvation of prototrophic cells for one of three essential nutrients (glucose, nitrogen, ...or phosphate) and compared those results with those obtained with cells growing slowly due to nutrient limitation. These studies address two related questions: (1) Is quiescence a state distinct from any attained during mitotic growth, and (2) does the nature of quiescence differ depending on the means by which it is induced? We found that either limitation or starvation for any of the three nutrients elicits all of the physiological properties associated with quiescence, such as enhanced cell wall integrity and resistance to heat shock and oxidative stress. Moreover, the starvations result in a common transcriptional program, which is in large part a direct extrapolation of the changes that occur during slow growth. In contrast, the metabolic changes that occur upon starvation and the genetic requirements for surviving starvation differ significantly depending on the nutrient for which the cell is starved. The genes needed by cells to survive starvation do not overlap the genes that are induced upon starvation. We conclude that cells do not access a unique and discrete G(0) state, but rather are programmed, when nutrients are scarce, to prepare for a range of possible future stressors. Moreover, these survival strategies are not unique to quiescence, but are engaged by the cell in proportion to nutrient scarcity.
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