Lnc-PFAR facilitates autophagy and exacerbates pancreatic fibrosis by reducing pre-miR-141 maturation in chronic pancreatitis

Chronic pancreatitis (CP) is described as progressive inflammatory fibrosis of pancreas, accompanied with irreversible impaired endocrine and exocrine insufficiency. Pancreatic stellate cells (PSCs) are widely distributed in the stroma of the pancreas and PSCs activation has been shown as one of the leading causes for pancreatic fibrosis. Our previous study has revealed that autophagy is dramatically activated in CP tissues, which facilitates PSCs activation and pancreatic fibrosis. Long non-coding RNAs (LncRNAs) have been recognized as crucial regulators for fibrosis-related diseases. LncRNAs interact with RNA binding protein or construct competitive endogenous RNA (ceRNA) hypothesis which elicited the fibrotic processes. Until now, the effects of lncRNAs on PSCs activation and pancreatic fibrosis have not been clearly explored. In this study, a novel lncRNA named Lnc-PFAR was found highly expressed in mouse and human CP tissues. Our data revealed that Lnc-PFAR facilitates PSCs activation and pancreatic fibrosis via RB1CC1-induced autophagy. Lnc-PFAR reduces miR-141 expression by suppressing pre-miR-141 maturation, which eventually upregulates the RB1CC1 and fibrosis-related indicators expression. Meanwhile, Lnc-PFAR enhanced PSCs activation and pancreatic fibrosis through trigging autophagy. Our study interrogates a novel lncRNA-induced mechanism in promoting the development of pancreatic fibrosis, and Lnc-PFAR is suggested to be a prospective therapeutic target in clinical scenarios.Subject terms: RNAi, Diagnostic markers, Chronic pancreatitis     

MiR-27a-3p enhances the cisplatin sensitivity in hepatocellular carcinoma cells through inhibiting PI3K/Akt pathway

MicroRNAs (miRNAs) play an important role in drug resistance, and it is reported that miR-27a-3p regulated the sensitivity of cisplatin in breast cancer, lung cancer and ovarian cancer. However, the relationship between miR-27a-3p and chemosensitivity of cisplatin in hepatocellular carcinoma (HCC) was unclear, especially the underlying mechanism was unknown. In the present study, we analyzed miR-27a-3p expression levels in 372 tumor tissues and 49 adjacent tissues in HCC samples from TCGA database, and found that the miR-27a-3p was down-regulated in HCC tissues. The level of miR-27a-3p was associated with metastasis, Child–Pugh grade and race. MiR-27a-3p was regarded as a favorable prognosis indicator for HCC patients. Then, miR-27a-3p was overexpressed in HepG2 cell, and was knocked down in PLC cell. Next, we conducted a series of in vitro assays, including MTT, apoptosis and cell cycle assays to observe the biological changes. Further, inhibitor rate and apoptosis rate were detected with pre- and post-cisplatin treatment in HCC. The results showed that overexpression of miR-27a-3p repressed the cell viability, promoted apoptosis and increased the percentage of cells in G₀/G₁ phase. Importantly, overexpression of miR-27a-3p significantly increased the inhibitor rate and apoptosis rate with cisplatin intervention. Besides, we found that miR-27a-3p added cisplatin sensitivity potentially through regulating PI3K/Akt signaling pathway. Taken together, miR-27a-3p acted as a tumor suppressor gene in HCC cells, and it could be useful for modulating cisplatin sensitivity in chemotherapy.     

浙江省松阳县黄山松种群的密度与生物量动态

 本文研究了浙江省松阳县关山源地区黄山松种群的密度与生物量动态以及它们之间的相互关系。黄山松是该地区森林演替中的先锋种群之一。在演替过程中,黄山松种群的动态可分成三个阶段。大约在黄山松种群入侵次生裸地的最初10年期间,种群的密度和生物量迅速增长(阶段Ⅰ)。此后,种群密度达到饱和,由于自疏作用出现以及其他阔叶树种的入侵,种群密度开始急剧下降,个体平均重量和种群生物量迅速增长(阶段Ⅱ),–3/2自疏定律适用于种群动态的此阶段。随着阔叶树种进入林冠层,虽然个体平均重量仍缓慢增长,黄山松种群的密度和种群生物量逐渐下降直至退出群落(阶段Ⅲ)。但在一些特殊生境中(如裸岩陡坡或山脊),黄山松种群可形成稳定的地形顶极群落,其种群密度、个体平均重量和种群生物量可长期维持相对稳定的状态。     

Structure insights into mechanisms of ATP hydrolysis and the activation of human heat-shock protein 90

The activation of molecular chaperone heat-shock protein 90 (Hsp90) is dependent on ATP binding and hydrolysis, which occurs in the N-terminal domains of protein. Here, we have determined three crystal structures of the N-terminal domain of human Hsp90 in native and in complex with ATP and ATP analog, providing a clear view of the catalytic mechanism of ATP hydrolysis by Hsp90. Additionally, the binding of ATP leads the N-terminal domains to be an intermediate state that could be used to partially explain why the isolated N-terminal domain of Hsp90 has very weak ATP hydrolytic activity.     

Increased Placental Growth Factor in Cerebrospinal Fluid of Patients with Epilepsy

Recent studies suggest that angiogenesis and vascular endothelial growth factor (VEGF) are involved in the pathophysiology of epilepsy. However, relatively little data are available linking placenta growth factor (PIGF) with epilepsy. In this study, we assessed concentrations of PIGF in cerebrospinal fluid (CSF) of 60 epileptic patients and 24 non-seizure subjects using sandwich enzyme-linked immunosorbent assays. Epileptic patients in general had higher concentration of CSF-PIGF than controls (7.95 ± 0.88 ng/l vs. 5.87 ± 0.79 ng/l, P < 0.01). CSF-PIGF level in secondary epileptic patients (8.59 ± 1.26 ng/l) was higher than that in idiopathic epileptic patients (7.62 ± 0.20 ng/l) (P < 0.05). In idiopathic epilepsy, CSF-PIGF level in patients with high seizure frequency was higher than those in patients with low seizure frequency and seizure-free in recent 3 years (7.78 ± 0.23 ng/l vs. 7.49 ± 0.09 ng/l and 7.59 ± 0.10 ng/l, P < 0.05). Concentration of CSF-PIGF in patients with a disease duration of > 5 years was higher than those in patients with durations of 1-5 years and <1 year (7.72 ± 0.20 ng/l vs. 7.52 ± 0.09 ng/l and 7.41 ± 0.07 ng/l, P < 0.05). These results indicate that preexisting brain damage, seizure frequency and disease duration are important factors contributing to elevated PIGF.     

Control of pollen-mediated gene flow in transgenic trees

Pollen elimination provides an effective containment method to reduce direct gene flow from transgenic trees to their wild relatives. Until now, only limited success has been achieved in controlling pollen production in trees. A pine (Pinus radiata) male cone-specific promoter, PrMC2, was used to drive modified barnase coding sequences (barnaseH102E, barnaseK27A, and barnaseE73G) in order to determine their effectiveness in pollen ablation. The expression cassette PrMC2-barnaseH102E was found to efficiently ablate pollen in tobacco (Nicotiana tabacum), pine, and Eucalyptus (spp.). Large-scale and multiple-year field tests demonstrated that complete prevention of pollen production was achieved in greater than 95% of independently transformed lines of pine and Eucalyptus (spp.) that contained the PrMC2-barnaseH102E expression cassette. A complete pollen control phenotype was achieved in transgenic lines and expressed stably over multiple years, multiple test locations, and when the PrMC2-barnaseH102E cassette was flanked by different genes. The PrMC2-barnaseH102E transgenic pine and Eucalyptus (spp.) trees grew similarly to control trees in all observed attributes except the pollenless phenotype. The ability to achieve the complete control of pollen production in field-grown trees is likely the result of a unique combination of three factors: the male cone/anther specificity of the PrMC2 promoter, the reduced RNase activity of barnaseH102E, and unique features associated with a polyploid tapetum. The field performance of the PrMC2-barnaseH102E in representative angiosperm and gymnosperm trees indicates that this gene can be used to mitigate pollen-mediated gene flow associated with large-scale deployment of transgenic trees.     

大鼠肾髓质活体微循环及观察方法

采用肾乳头暴露方法活体观察Sprague-Dawley大鼠肾髓质微循环。结果发现:正常成年大鼠肾乳头可暴露1.1±0.5mm; 乳头表面直血管数29.8±6.3;升、降支比例3.4:1。升支平均直径13.68±6.13μm,降支10.8±2.57μm。肾乳头连续暴露观察10h,其微循环未发生明显病理性改变。说明这一方法可以用于肾髓质微循环活体研究。     

Design and synthesis of novel photoaffinity probes for study of the target proteins of oleanolic acid

To explore the molecular mechanisms of oleanolic acid, two novel photoaffinity probes were synthesized based on the structure-activity relationship reported previously. Their potency were evaluated in an enzyme inhibition assay against rabbit muscle glycogen phosphorylase a (RMGPa), a known target protein of oleanolic acid. The inhibitory activity of probe 2 was only about two-fold less potent than the mother compound oleanolic acid. The photoaffinity labeling experiments were also performed and two proteins were specifically tagged by probe 2. The results suggest that the synthesized probes could be used as powerful tools to isolate and identify the target proteins of oleanolic acid.     

Multiple adaptive losses of alanine-glyoxylate aminotransferase mitochondrial targeting in fruit-eating bats

The enzyme alanine-glyoxylate aminotransferase 1 (AGT) functions to detoxify glyoxylate before it is converted into harmful oxalate. In mammals, mitochondrial targeting of AGT in carnivorous species versus peroxisomal targeting in herbivores is controlled by two signal peptides that correspond to these respective organelles. Differential expression of the mitochondrial targeting sequence (MTS) is considered an adaptation to diet-specific subcellular localization of glyoxylate precursors. Bats are an excellent group in which to study adaptive changes in dietary enzymes; they show unparalleled mammalian dietary diversification as well as independent origins of carnivory, frugivory, and nectarivory. We studied the AGT gene in bats and other mammals with diverse diets and found that the MTS has been lost in unrelated lineages of frugivorous bats. Conversely, species exhibiting piscivory, carnivory, insectivory, and sanguinivory possessed intact MTSs. Detected positive selection in the AGT of ancestral fruit bats further supports adaptations related to evolutionary changes in diet.     

Cell expansion and microtubule behavior in ray floret petals of Gerbera hybrida: responses to light and gibberellic acid

It is still unclear how light and gibberellins are integrated to regulate petal size. Here, we report that light improves both the length and the width of the ray floret petals in G. hybrid, but GA(3) promotes only the petal length. It is also revealed that the control of the petal size by light and GA(3) depends on modulating the cell size, which is governed by the behavior of cortical microtubule.Light and gibberellins are important regulators of plant organ growth. However, little is known about their roles in petal size determination. Here, we report how light and gibberellic acid (GA(3)) signals are integrated to regulate the ray floret (Rf) size in Gerbera hybrida. The inflorescences of G. hybrida at stages 1.5 were cultivated in vitro for 9 d followed by the determination of the Rf petal size. Results demonstrated that the light signal significantly enhanced both the length and the width of Rf petals, but GA(3) promoted only the petal length. Moreover, GA(3) displayed a synergistic positive effect on the length but an antagonistic effect on the width with the light signal. Measurements of the petal cells revealed that the cell size, not the cell number, exhibited a dominant contribution to the petal size in response to light and GA(3) signals. Furthermore, light and GA(3) signals not only induced an obvious reorientation of cortical microtubules (MTs) into transverse arrays but also promoted the recovery of the MT lengths in petal cells following oryzalin (an MT depolymerizing agent) treatment. Importantly, disruption of the MT lengths and arrays by oryzalin could inhibit the cell expansion and the petal enlargement induced by light or/and GA(3) signals. Taken together, it is concluded that the control of the petal size by light and GA(3) signals mainly depends on modulating the cell size and, moreover, the organization of the cortical MTs plays a crucial role in the control of the cell size and hence the Rf petal growth.