The plant-specific ABERRANT GAMETOGENESIS 1 gene is essential for meiosis in rice

Meiotic recombination plays a central role in maintaining genome stability and increasing genetic diversity. Although meiotic progression and core components are widely conserved across kingdoms, significant differences remain among species. Here we identify a rice gene ABERRANT GAMETOGENESIS 1 (AGG1) that controls both male and female gametogenesis. Cytological and immunostaining analysis showed that in the osagg1 mutant the early recombination processes and synapsis occurred normally, but the chiasma number was dramatically reduced. Moreover, OsAGG1 was found to interact with ZMM proteins OsHEI10, OsZIP4, and OsMSH5. These results suggested that OsAGG1 plays an important role in crossover formation. Phylogenetic analysis showed that OsAGG1 is a plant-specific protein with a highly conserved N-terminal region. Further genetic and protein interaction analyses revealed that the conserved N-terminus was essential for the function of the OsAGG1 protein. Overall, our work demonstrates that OsAGG1 is a novel and critical component in rice meiotic crossover formation, expanding our understanding of meiotic progression. This study identified a plant-specific gene ABERRANT GAMETOGENESIS 1 that is required for meiotic crossover formation in rice. The conserved N-terminus of the AGG1 protein was found to be essential for its function.

Identification of Abnormal Circuit Dynamics in Major Depressive Disorder via Multiscale Neural Modeling of Resting-State fMRI

Resting-state functional magnetic resonance imaging (rs-fMRI) studies have focused primarily on characterizing functional or effective connectivity of discrete brain regions. A major drawback of this approach is that it does not provide a mechanistic understanding of brain cognitive function or dysfunction at cellular and circuit levels. To overcome this limitation, we combined the methods of computational neuroscience with traditional macroscale connectomic analysis and developed a Multiscale Neural Model Inversion (MNMI) framework that links microscale circuit interaction with macroscale network dynamics and estimates both local coupling and inter-regional connections via stochastic optimization based on blood oxygen-level dependent (BOLD) rs-fMRI. We applied this method to the rs-fMRI data of 66 normal healthy subjects and 66 individuals with major depressive disorder (MDD) to identify potential biomarkers at both local circuit and global network level. Results suggest that the recurrent excitation and inhibition within the dorsal lateral prefrontal cortex (dlPFC) might be disrupted in MDD, consistent with the commonly accepted hypothetical model of MDD. In addition, recurrent excitation in the thalamus was found to be abnormally elevated, which may be responsible to abnormal thalamocortical oscillations often observed in MDD. Overall, our modeling approach holds the promise to overcome the limitation of traditional large-scale connectome modeling by providing hidden mechanistic insights into neuroanatomy, circuit dynamics and pathophysiology.

Treatment-naïve first episode depression classification based on high-order brain functional network

BACKGROUND

Recent functional connectivity (FC) studies have proved the potential value of resting-state functional magnetic resonance imaging (rs-fMRI) in the study of major depressive disorder (MDD); yet, the rs-fMRI-based individualized diagnosis of MDD is still challenging.

METHODS

We enrolled 82 treatment-naïve first episode depression (FED) adults and 72 matched normal control (NC). A computer-aided diagnosis framework was utilized to classify the FEDs from the NCs based on the features extracted from not only traditional "low-order" FC networks (LON) based on temporal synchronization of original rs-fMRI signals, but also "high-order" FC networks (HON) that characterize more complex functional interactions via correlation of the dynamic (time-varying) FCs. We contrasted a classifier using HON feature (C_HON) and compared its performance with using LON only (C_LON). Finally, an integrated classification model with both features was proposed to further enhance FED classification.

RESULTS

The C_HON had significantly improved diagnostic accuracy compared to the C_LON (82.47% vs. 67.53%). Joint classification further improved the performance (83.77%). The brain regions with potential diagnostic values mainly encompass the high-order cognitive function-related networks. Importantly, we found previously less-reported potential imaging biomarkers that involve the vermis and the crus II in the cerebellum.

LIMITATIONS

We only used one imaging modality and did not examine data from different subtypes of depression.

CONCLUSIONS

Depression classification could be significantly improved by using HON features that better capture the higher-level brain functional interactions. The findings suggest the importance of higher-level cerebro-cerebellar interactions in the pathophysiology of MDD.

A dedicated high-quality service for the management of patients with an inherited risk of colorectal cancer

AIM

To demonstrate the quality improvement associated with the implementation of a specialist family history of bowel cancer service in secondary care.

METHOD

The following outcomes were assessed: (1) adherence to the British Society of Gastroenterology (BSG) guidelines for colonoscopic surveillance of individuals with a family history of colorectal cancer (CRC); (2) adherence to the revised Bethesda criteria for the identification of CRC patients with suspected Lynch syndrome; (3) identification of inherited syndromes with increased CRC risk; and (4) colonoscopic adenoma detection rate. Data were collected for a 21-month period before and after the establishment of this service for all patients who underwent colonoscopic surveillance for a family history of CRC and all patients newly diagnosed with CRC. Analyses compared the number of colonoscopies performed that were not indicated by BSG guidelines, the average number of years early that patients were screened, the adenoma detection rate and the rate of tumour testing for mismatch repair genes before and after the implementation of the service.

RESULTS

Following the establishment of the service there was a reduction in the number of colonoscopies not indicated by BSG guidelines (39.6% before and 5.8% after, P < 0.001, chi-square test) and surveillance colonoscopy took place at a more appropriate age (10.6 years too early before and 5.9 years early after, P = 0.01, t-test). There was an increased adenoma detection rate (17% before and 31.9% after, P < 0.01, chi-square test) and increased tumour MMR testing (3.4% before and 91.8% after, P < 0.01, chi-square test).

CONCLUSION

The introduction of a family history of bowel cancer service results in improved patient care through improved adherence to guidelines for colonoscopic surveillance and increased cancer detection rates.

Altered Whole-Brain Functional Topological Organization and Cognitive Function in Type 2 Diabetes Mellitus Patients

Type 2 diabetes mellitus (T2DM) is associated with cognitive dysfunction and may even progress to dementia. However, the underlying mechanism of altered functional topological organization and cognitive impairments remains unclear. This study explored the topological properties of functional whole brain networks in T2DM patients with graph theoretical analysis using a resting-state functional magnetic resonance imaging (rs-fMRI) technique. Thirty T2DM patients (aged 51.77 ± 1.42 years) and 30 sex-, age-, and education-matched healthy controls (HCs) (aged 48.87 ± 0.98 years) underwent resting-state functional imaging in a 3.0 T MR scanner in addition to detailed neuropsychological and laboratory tests. Then, graph theoretical network analysis was performed to explore the global and nodal topological alterations in the functional whole brain networks of the T2DM patients. Finally, correlation analyses were performed to investigate the relationship between the altered topological parameters, cognitive performances and clinical variables. Compared to HCs, we found that T2DM patients displayed worse performances in general cognitive function and several cognitive domains, including episodic memory, attention and executive function. In addition, T2DM patients showed a higher small-worldness (σ), a higher normalized clustering coefficient (γ) and a higher local efficiency (E_loc). Moreover, decreased nodal topological properties were mainly distributed in the occipital lobes, frontal lobes, left median cingulate and paracingulate gyri, and left amygdala, while increased nodal topological properties were mainly distributed in the right gyrus rectus, right anterior cingulate and paracingulate gyri, right posterior cingulate gyrus, bilateral caudate nucleus, bilateral cerebellum 3, bilateral cerebellum crus 1, vermis (1, 2) and vermis 3. Some disrupted nodal topological properties were correlated with cognitive performance and HbA1c levels in T2DM patients. This study shows altered functional topological organization in T2DM patients, mainly suggesting a compensation mechanism of the functional whole brain network in the relatively early stage to counteract cognitive impairments.

EphrinB2/EphB4 Signaling Regulates DPSCs to Induce Sprouting Angiogenesis of Endothelial Cells

Dental pulp stem cells (DPSCs) are capable of facilitating angiogenesis resembling pericytes when located adjacent to endothelial cells (ECs). Nevertheless, the precise mechanisms orchestrating their proangiogenic functions remain unclear. Using a 3-dimensional (3-D) fibrin gel model, we aimed to investigate whether EphrinB2/EphB4 signaling in DPSCs plays a role in supporting vascular morphogenesis mediated by ECs, together with the underlying mechanism involved. The EphrinB2/EphB4 signaling was inhibited either by a pharmacological inhibitor of EphB4 receptor or by knocking down the expressions of EphrinB2 and EphB4 using lentiviral small hairpin RNA (shRNA). DPSCs were either encapsulated in fibrin gel together with human umbilical vein endothelial cells (HUVECs) or cultured as a monolayer on top of HUVECs to investigate both paracrine and juxtacrine interactions simultaneously. Following 10 d of direct coculture, we found that pharmacological inhibition of EphrinB2/EphB4 signaling severely impaired vessel formation and laminin deposition. When directly cocultured with HUVECs, knockdown of EphrinB2 or EphB4 in DPSCs significantly inhibited endothelial sprouting, resulting in less capillary sprouts with reduced vessel length (P < 0.05). By contrast, when DPSCs were not in direct contact with HUVECs, attenuation of EphrinB2 or EphB4 expression levels in DPSCs did not exert any significant effects on capillary morphogenesis. Noticeably, exogenous stimulation with soluble EphrinB2-Fc or EphB4-Fc (1 µg/mL) enhanced vascular endothelial growth factor (VEGF) secretion from DPSCs, thereby moderately promoting angiogenic cascades in the fibrin matrix. This study, for the first time, reveals a crucial role of EphrinB2/EphB4 signaling in regulating the capacity of DPSCs to induce sprouting angiogenesis. These findings advance our understanding of postnatal angiogenesis and may have future regenerative medicine applications.

[Correlation between CTL and Th1 cell proportion in peripheral blood of liver transplantation recipients and the success of hepatitis B vaccination]

Objective: To investigate the correlation between the proportion of CTL and Th1 cells in peripheral blood of liver transplant recipients and the success of hepatitis B vaccination. Methods: The subjects of this study were liver transplantation recipients with chronic HBV-related liver diseases in Organ transplantation institute of the third medical center of PLA general hospital. Subjects were randomly divided into two groups for prospective study. In the rapid group, one dose of 40 μg hepatitis B vaccine was administered at 0, 1, 2and 3 months, and one dose of 20 μg hepatitis B vaccine was administered at 4, 5 and 6 months. In the rapid-enhanced group, one dose of 40 μg hepatitis B vaccine was administered at 0, 1, 2 and 3 months, and one dose of 60 μg hepatitis B vaccine was administered at 4, 5 and 6months. Compare and analyze the success rate of inoculation, the titer of hepatitis B surface antibody (anti-HBs), the proportion of CTL cells in CD8(+)T cells and Th1 cells in CD4(+)T cells. Correlation analysis was performed for CTL and Th1 cells and anti-HBs, Observe the safety of vaccination. Results: The inoculation success rate, anti-HBs growth rate, CTL cell percentage increase and Th1 cell percentage increase in the rapid enhancement group were all higher than those in the rapid enhancement group, and the differences were statistically significant, they were 38.3% (23/60) vs 21.7% (13/60) (P=0.046), 91.3(72.5,124.2) vs 22.1(12.4, 31.6) (P=0.001), 1.4(0.8,1.9) vs 0.4(0.2,1.4) (P=0.001) and 7.4±2.6 vs 5.6±3.7 (P=0.001) respectively. The percentage increase of CTL cells and Th1 cells in the successful group was greater than that in the non-successful group, and the difference was statistically significant. They were 1.9(1.4,2.5) vs 0.1(0.0,1.1) (P=0.024) and 9.6±3.1 vs 2.4±2.0 (P<0.001). There was no significant correlation between anti-HBs increase (105.5±37.1) and CTL increase 1(0,3) (P=0.099), while there was significant positive correlation with Th1 increase 7(2,11) (P<0.001). No rejection reaction occurred during the study period, and there was no special abnormal change in the safety index. Conclusion: Reasonable increase of vaccine dose can up-regulate Th1 cell expression and promote the generation of anti-HBs.

Application of a machine learning method to whole brain white matter injury after radiotherapy for nasopharyngeal carcinoma

Background

The purpose/aim of this study was to 1) use magnetic resonance diffusion tensor imaging (DTI), fibre bundle/tract-based spatial statistics (TBSS) and machine learning methods to study changes in the white matter (WM) structure and whole brain WM network in different periods of the nasopharyngeal carcinoma (NPC) patients after radiotherapy (RT), 2) identify the most discriminating WM regions and WM connections as biomarkers of radiation brain injury (RBI), and 3) supplement the understanding of the pathogenesis of RBI, which is useful for early diagnosis in the clinic.

Methods

A DTI scan was performed in 77 patients and 67 normal controls. A fractional anisotropy map was generated by DTIFit. TBSS was used to find the region where the FA differed between the case and control groups. Each resulting FA value image is registered with each other to create an average FA value skeleton. Each resultant FA skeleton image was connected to feature vectors, and features with significant differences were extracted and classified using a support vector machine (SVM). Next, brain segmentation was performed on each subject’s DTI image using automated anatomical labeling (AAL), and deterministic white matter fiber bundle tracking was performed to generate symmetrical brain matrix, select the upper triangular component as a classification feature. Two-sample t-test was used to extract the features with significant differences, then classified by SVM. Finally, we adopted a permutation test and ROC curves to evaluate the reliability of the classifier.

Results

For FA, the accuracy of classification between the 0–6, 6–12 and > 12 months post-RT groups and the control group was 84.5, 83.9 and 74.5%, respectively. In the case groups, the FA with discriminative ability was reduced, mainly in the bilateral cerebellum and bilateral temporal lobe, with prolonged time, the damage was aggravated. For WM connections, the SVM classifier classification recognition rates of the 0–6, 6–12 and > 12 months post-RT groups reached 82.5, 78.4 and 76.3%, respectively. The WM connections with discriminative ability were reduced.

Conclusions

RBI is a disease involving whole brain WM network anomalies. These brain discriminating WM regions and WM connection modes can supplement the understanding of RBI and be used as biomarkers for the early clinical diagnosis of RBI.

Local Diffusion Homogeneity Provides Supplementary Information in T2DM-Related WM Microstructural Abnormality Detection

Objectives: We aimed to investigate whether an inter-voxel diffusivity metric (local diffusion homogeneity, LDH), can provide supplementary information to traditional intra-voxel metrics (i.e., fractional anisotropy, FA) in white matter (WM) abnormality detection for type 2 diabetes mellitus (T2DM).

Methods: Diffusion tensor imaging was acquired from 34 T2DM patients and 32 healthy controls. Voxel-based group-difference comparisons based on LDH and FA, as well as the association between the diffusion metrics and T2DM risk factors [i.e., body mass index (BMI) and systolic blood pressure (SBP)], were conducted, with age, gender and education level controlled.

Results: Compared to the controls, T2DM patients had higher LDH in the pons and left temporal pole, as well as lower FA in the left superior corona radiation (p < 0.05, corrected). In T2DM, there were several overlapping WM areas associated with BMI as revealed by both LDH and FA, including right temporal lobe and left inferior parietal lobe; but the unique areas revealed only by using LDH included left inferior temporal lobe, right supramarginal gyrus, left pre- and post-central gyrus (at the semiovale center), and right superior radiation. Overlapping WM areas that associated with SBP were found with both LDH and FA, including right temporal pole, bilateral orbitofrontal area (rectus gyrus), the media cingulum bundle, and the right cerebellum crus I. However, the unique areas revealed only by LDH included right inferior temporal lobe, right inferior occipital lobe, and splenium of corpus callosum.

Conclusion: Inter- and intra-voxel diffusivity metrics may have different sensitivity in the detection of T2DM-related WM abnormality. We suggested that LDH could provide supplementary information and reveal additional underlying brain changes due to diabetes.

Moderate intensity continuous training reverses the detrimental effects of ovariectomy on RyR1 phosphorylation in rat skeletal muscle

High 17β-Estradiol (E2) concentrations in isolated ventricular myocytes as well as a lack of ovarian hormones in cardiac muscle of ovariectomized (OVX) rodents has been shown to lead to arrhythmogenic effects by inducing post-translational modifications, including phosphorylation of the sarcoplasmic reticulum (SR) Ca²⁺ release channel ryanodine receptor-2 (RyR2). The effects of estrogens on the phosphorylation status of the RyR1 in skeletal muscle have not been investigated before. Furthermore, while high intensity exercise has been shown to increase RyR phosphorylation, there is no data on the effects of moderate intensity continuous training (MICT). The aims of the study were to investigate the effects of a 3-day treatment with low (1 nM, moderate (5 nM) and high (10 nM, 100 nM) E2 concentrations on RyR1 mRNA and protein expression and phosphorylation status (pRyRSer²⁸⁴⁴) in cultured C2C12 myotubes and to study the effects of OVX on RyR1 expression and phosphorylation in rat skeletal muscle in combination with 3 weeks of MICT. Treatment with low, physiological E2 concentrations reduced dihydropyridine receptor (DHPR) and RyR1 mRNA content in C2C12 myotubes compared to untreated control cells, whereas RyR1 protein phosphorylation (pRyRSer²⁸⁴⁴) was significantly increased after treatment with high, non-physiological E2 concentrations (p ≤ 0.05). RyR1 protein content (p ≤ 0.05) and pRyRSer²⁸⁴⁴ (p ≤ 0.05) were significantly elevated in skeletal muscle of OVX vs. sham-operated rats. Importantly, pRyRSer²⁸⁴⁴ levels were similar to sham-operated controls in OVX rats after MICT (OVX vs. OVX + MICT, p ≤ 0.05). Our results indicate, that one of the actions of estrogens is to alter skeletal muscle Ca²⁺ homeostasis by modulating the expression and phosphorylation of the RyR1 in skeletal muscle. Notably, regular MICT was able to counteract RyR1 phosphorylation in skeletal muscle of OVX rats.

Chidamide and 5-flurouracil show a synergistic antitumor effect on human colon cancer xenografts in nude mice

Chidamide is a novel histone deacetylase (HDAC) inhibitor that increases the acetylation of histone H3 by inhibiting the activity of HDAC1 and HDAC2. We previously found that treatment of human colon cancer cells with chidamide led to cell apoptosis and cell cycle arrest at G0/1 phase in vitro. The present study extended the observations in vivo and explored the underlying molecular mechanisms. In nude mice bearing human colon cancer LoVo cell xenografts, chidamide alone or in combination with 5-flurouracil (5-Fu) reduced the expression of HDAC1 and HDAC2, accompanied with increased acetylation of histone H3. Chidamide alone inhibited the tumor growth and induce cell apoptosis in tumor-bearing mice. Combined treatment of chidamide with 5-Fu enhanced the anti-tumor activity of 5-Fu. Western blotting analysis showed that chidamide alone or in combination with 5-Fu upregulated the expressions of cleaved Caspase-3 and cleaved poly-ADP (adenosine diphosphate)-ribose polymerase (PARP). In addition, chidamide alone or in combination with 5-Fu increased the p53, phosphorylated-p53 (p-p53), p21 and γH2AX levels, but suppressed cyclin dependent kinase 4 (CDK4) expression in tumor cells. Chidamide alone or in combination with 5-Fu down regulated the expressions of p-AKT, p-mammalian target of rapamycin (mTOR), p-p70S6K, p-Raf, and p44/42 mitogen activated protein kinase (Erk1/2), indicating the blockage of these signaling pathways. The results demonstrated that chidamide alone or in combination with 5-Fu exerted anti-tumor activity in nude mice bearing human colon cancer LoVo cell xenografts, and several signaling pathways might be involved in the chidamide-induced tumor growth inhibition and tumor cell apoptosis.

The ATP-binding cassette (ABC) transporter OsABCG3 is essential for pollen development in rice

BACKGROUND

The pollen wall, which protects male gametophyte against various stresses and facilitates pollination, is essential for successful reproduction in flowering plants. The pollen wall consists of gametophyte-derived intine and sporophyte-derived exine. From outside to inside of exine are tectum, bacula, nexine I and nexine II layers. How these structural layers are formed has been under extensive studies, but the molecular mechanisms remain obscure.

RESULTS

Here we identified two osabcg3 allelic mutants and demonstrated that OsABCG3 was required for pollen development in rice. OsABCG3 encodes a half-size ABCG transporter localized on the plasma membrane. It was mainly expressed in anther when exine started to form. Loss-function of OsABCG3 caused abnormal degradation of the tapetum. The mutant pollen lacked the nexine II and intine layers, and shriveled without cytoplasm. The expression of some genes required for pollen wall formation was examined in osabcg3 mutants. The mutation did not alter the expression of the regulatory genes and lipid metabolism genes, but altered the expression of lipid transport genes.

CONCLUSIONS

Base on the genetic and cytological analyses, OsABCG3 was proposed to transport the tapetum-produced materials essential for pollen wall formation. This study provided a new perspective to the genetic regulation of pollen wall development.

Mixed adenoneuroendocrine carcinoma of the colon and rectum

Mixed adenoneuroendocrine carcinoma (MANEC) are rare cancers of the gastrointestinal (GI) and pancreatobiliary tract. They are characterized by the presence of a combination of epithelial and neuroendocrine elements, where each component represents at least 30% of the tumour. Review of literature and consolidation of clinicopathological data. Sixty-one cases of colorectal MANEC have been reported in literature and one seen in this centre. The median age of the patients affected was 61.9 ± 12.4 years (20-94 years). Male to female ratio is 1.0:1.2. Presentations were similar to other colorectal malignancies. 58.0% of colorectal MANECs were found in the right colon, 8.1% cases in the transverse, 16.1% in the left colon, 16.1% in the rectum. These tumours appeared invasiveness 79.1% were T3-T4. Over 90% of cases were presented with metastatic disease. The majority of patient underwent surgical resection of the primary cancer (96.6%). Of these, 10 operations (17.9%) were emergency operations due to obstruction, perforation, or bleeding. Three patients received first line palliative care. In eight cases (13.8%), patients underwent adjuvant chemotherapy. The median overall survival after diagnosis was 10 ± 2.4 months (95% CI: 5.37-14.64 months). MANECs are rare but aggressive colorectal cancers. Surgical resection of localized disease with adjuvant chemotherapy appears to significantly improve survival in small case series. Further understanding through the sharing of experiences is required.

Comparison of guidelines for the management of rectal cancer

A comparison between NCCN, ESMO and JSCCR Guidelines is presented, concerning the treatment of rectal cancer, with an analysis and discussion of their discrepancies. Differences indicate areas for research.

First Search for Nontensorial Gravitational Waves from Known Pulsars

We present results from the first directed search for nontensorial gravitational waves. While general relativity allows for tensorial (plus and cross) modes only, a generic metric theory may, in principle, predict waves with up to six different polarizations. This analysis is sensitive to continuous signals of scalar, vector, or tensor polarizations, and does not rely on any specific theory of gravity. After searching data from the first observation run of the advanced LIGO detectors for signals at twice the rotational frequency of 200 known pulsars, we find no evidence of gravitational waves of any polarization. We report the first upper limits for scalar and vector strains, finding values comparable in magnitude to previously published limits for tensor strain. Our results may be translated into constraints on specific alternative theories of gravity.