Transcriptome sequencing and differential expression analysis of seed starch accumulation in Chinese chestnut Metaxenia

Background

Chestnut seeds are important kinds of edible nuts rich in starch and protein. The characteristics and nutrient contents of chestnut have been found to show obvious metaxenia effects in previous studies. To improve the understanding of the effect of metaxenia on chestnut starch and sucrose metabolism, this study used three varieties of chestnut, ‘Yongfeng 1’, ‘YongRen Zao’ and ‘Yimen 1’, as male parents to pollinate the female parent, ‘Yongfeng 1’, and investigated the mechanisms of starch and sucrose metabolism in three starch accumulation stages (70 (S1), 82 (S2), and 94 (S3) days after pollination, DAP) in chestnut seed kernels.

Result

Most carbohydrate metabolism genes were highly expressed in YFF (self-pollinated ‘Yongfeng 1’) in stage S2 and in YFR (‘Yongfeng 1’ × ‘Yongren Zao’) and YFM (‘Yongfeng 1’ × ‘Yimen 1’) in stage S3. In stage S3, hub genes encoding HSF_DNA-binding, ACT, Pkinase, and LIM proteins and four transcription factors were highly expressed, with YFF showing the highest expression, followed by YFR and YFM. In addition, transcriptome analysis of the kernels at 70, 82 and 94 DAP showed that the starch granule-bound starch synthase (EC 2.4.1.242) and ADP-glucose pyrophosphorylase (EC 2.7 .7.27) genes were actively expressed at 94 DAF. Chestnut seeds regulate the accumulation of soluble sugars, reducing sugars and starch by controlling glycosyl transferase and hydrolysis activity during development.

Conclusion

These results and resources have important guiding significance for further research on starch and sucrose metabolism and other types of metabolism related to chestnut metaxenia.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12864-021-07923-5.

Whole-lesion histogram analysis of mono-exponential and bi-exponential diffusion-weighted imaging in differentiating lung cancer from benign pulmonary lesions using 3 T MRI

AIM

To investigate whether whole-lesion histogram analysis of apparent diffusion coefficient (ADC) values derived from mono-exponential and bi-exponential diffusion-weighted imaging (DWI) can differentiate lung cancer from benign pulmonary lesions.

MATERIALS AND METHODS

Thirty-two patients with lung cancer and 17 patients with benign pulmonary lesions were included retrospectively. All patients underwent DWI before surgery or biopsy. ADC histogram parameters, including mean, percentile values (10^th and 90^th), kurtosis, and skewness, were calculated independently by two radiologists. The histogram parameters were compared between patients with lung cancer and benign lesions. Receiver operating characteristic curves were constructed to evaluate the diagnostic performance.

RESULTS

The ADC_Mean, ADC_10th, D_Mean, D_10th were significantly lower in lung cancer (1.187 ± 0.144 × 10^-3; 0.440 ± 0.062 × 10^-3; 1.068 ± 0.108 × 10^-3; and 0.422 ± 0.049 × 10^-3 mm/s) compared to benign lesions (1.418 ± 0.274 × 10^-3; 0.555 ± 0.113 × 10^-3; 1.216 ± 0.149 × 10^-3; and 0.490 ± 0.044 × 10^-3 mm/s; p<0.05). The ADC_Skewness and D_Skewness were significantly different between lung cancer (2.35 ± 0.72; 2.58 ± 1.14) and benign lesions (1.85 ± 0.54; 1.59 ± 1.47; p<0.05). D_10th was robust in differentiating lung cancer from benign lesions. Using 0.453 × 10^-3 mm/s as the optimal threshold, the sensitivity, specificity, and accuracy of D_10th were 78.12%, 82.35%, and 79.6%, respectively.

CONCLUSION

Whole-lesion histogram analysis of ADC values derived by mono-exponential and bi-exponential DWI using 3 T magnetic resonance imaging helps distinguish lung cancer from benign pulmonary lesions.

Association between type 1 diabetes mellitus and reduced bone mineral density in children: a meta-analysis

In this meta-analysis, we analyzed 9 cross-sectional studies for an association between type 1 diabetes mellitus (T1DM) and bone mineral density (BMD) in children. We found that BMD Z-scores were significantly reduced in children with T1DM.

INTRODUCTION

Recent cross-sectional studies have examined how T1DM influences bone health in children and adolescents, but the relationship between T1DM and BMD remains unclear due to conflicting reports.

METHODS

In this meta-analysis, we systematically searched PubMed, Cochrane library, and Web of Science databases (for publications through March 12, 2020), and calculated weight mean difference (WMD) along with 95% confidence intervals (CI) using a random-effects model. Heterogeneity was evaluated using the I² method. The Newcastle-Ottawa Scale was used to assess the quality of the included studies.

RESULTS

Data were analyzed from 9 eligible studies, including a total of 1522 children and adolescents. These data were tested for an association between T1DM and BMD. This analysis found a significant decrease in BMD Z-score in the whole body (pooled WMD, - 0.47, 95% CI, - 0.92 to - 0.02, I² = 80.2%) and lumbar spine (pooled WMD, - 0.41, 95% CI, - 0.69 to - 0.12, I² = 80.3%) in children and adolescents with T1DM, which was consistent in published studies from Asia and South America, but inconsistent in the North America and Europe. Importantly, the differences in BMD Z-scores were independent of age, level of glucose control (HbA1c), and prepubertal stage. Sensitivity analyses did not modify these findings. Funnel plot and the Egger test did not reveal significant publication bias.

CONCLUSION

This meta-analysis suggests that T1DM may play a role in decreasing BMD Z-scores in the whole body and lumbar spine in children.

Engineering Oxaliplatin Prodrug Nanoparticles for Second Near-Infrared Fluorescence Imaging-Guided Immunotherapy of Colorectal Cancer

Colorectal cancer (CRC) ranks as the third common and the fourth lethal cancer type worldwide. Immune checkpoint blockade therapy demonstrates great efficacy in a subset of metastatic CRC patients, but precise activation of the antitumor immune response at the tumor site is still challenging. Here a versatile prodrug nanoparticle for second near-infrared (NIR-II) fluorescence imaging-guided combinatory immunotherapy of CRC is reported. The prodrug nanoparticles are constructed with a polymeric oxaliplatin prodrug (PBOXA) and a donor-spacer-acceptor-spacer-donor type small molecular fluorophore TQTCD. The later displays large Stokes shift (>300 nm), fluorescence emission over 1000 nm, and excellent photothermal conversion performance for NIR-II fluorescence imaging-guided photothermal therapy (PTT). The prodrug nanoparticles show seven times higher intratumoral OXA accumulation than free oxaliplatin. TQTCD-based PTT and PBOXA-induced chemotherapy trigger immunogenic cell death of the tumor cells and elicit antitumor immune response in a spatiotemporally controllable manner. Further combination of the prodrug nanoparticle-based PTT/chemotherapy with programmed death ligand 1 blockade significantly promotes intratumoral infiltration of the cytotoxic T lymphocytes and eradicates the CRC tumors. The NIR-II fluorescence imaging-guided immunotherapy may provide a promising approach for CRC treatment.

Relationship between inflammatory factors and arrhythmia and heart rate variability in OSAS patients

OBJECTIVE

Obstructive Sleep Apnea Syndrome (OSAS) is a disorder characterized by recurrent upper airway obstruction, apnea, and hypopnea, associated with decreased oxygen saturation and disturbed sleep structure during sleep. It was found that OSAS was associated with a variety of arrhythmia and conduction disorders, but the relationship between multiple types of arrhythmia and the severity of OSAS, and its possible mechanism remain unclear. The purpose of this study was to observe the main types of arrhythmia and the condition of heart rate variability (HRV) in patients with OSAS, to detect the levels of multiple inflammatory factors in serum of OSAS patients, and to observe the correlation between polysomnographic parameters or inflammatory factors, and arrhythmia or HRV, as well as its possible mechanisms.

PATIENTS AND METHODS

141 patients with suspected OSAS were collected in the Second Affiliated Hospital of Soochow University and Xinghua People's Hospital from February 2016 to February 2018. According to the sleep apnea hypopnea index (AHI), they were divided into control group (AHI <5, n = 34), mild-moderate OSAS group (5≤ AHI <30, n = 48), and severe OSAS group (AHI ≥30, n = 59). Clinical data such as gender and age were collected. All patients completed polysomnography (PSG), 24-hour Holter monitoring and blood routine, biochemical indexes and serum hs-CRP, TNF-α, IL-6, and IL-1β testing. The indicators in the three groups were compared, and the correlation between PSG parameters, HRV and inflammatory biomarkers was investigated.

RESULTS

Compared with control group, there were significant differences in age, sex ratio, BMI, uric acid, TC, and TG in the mild-moderate OSAS group (p<0.05), and in age, sex ratio, BMI, red blood cell count, hemoglobin, hematocrit, uric acid, FBS, TC, TG, LDL, and HDL in severe OSAS group (p<0.05). There were significant differences in gender ratio, BMI, red blood cell count, hemoglobin, hematocrit, uric acid, FBS, TC, TG, LDL, and HDL between mild-moderate OSAS group and severe OSAS group (p<0.05). Heart rate variability (HRV) parameters include SDNN, SDNN index, RMSSD, PNN50, LF, HF, and LF/HF. SDNN, PNN50, and HF in severe OSAS group and mild-moderate OSAS group were significantly lower than those in control group (p<0.05). LF/HF was significantly higher than that of control group (p<0.05). There was a significant difference in PNN50, HF, and LF/HF between severe OSAS group and mild-moderate OSAS group (p<0.05). In terms of inflammation, serum hs-CRP was significantly higher in mild-moderate OSAS group and severe OSAS group than that in control group (p<0.05). Serum IL-1β was significantly higher in mild-moderate OSAS group than that in severe OSAS group (p<0.05). There was no significant difference in other indicators (p>0.05). There was a significant positive correlation between hs-CRP and oxygen reduction index (ODI) (r=0.209, p=0.013) and a significant negative correlation with PNN50 (r=-0.188, p=0.025). There is no significant correlation between other indicators.

CONCLUSIONS

Systemic inflammatory reactions existed in patients with OSAS. With the increase of OSAS, inflammation was aggravated, especially serum hs-CRP. Hs-CRP was significantly and negatively correlated with PNN50 and positively correlated with ODI. The results suggested that the inflammatory response was involved in the occurrence of heart rate variability in OSAS patients.

Regulating Glucose Metabolism with Prodrug Nanoparticles for Promoting Photoimmunotherapy of Pancreatic Cancer

The low immunogenicity, insufficient infiltration of T lymphocytes, and dismal response to immune checkpoint blockade therapy pose major difficulties in immunotherapy of pancreatic cancer. Photoimmunotherapy by photodynamic therapy (PDT) can induce an antitumor immune response by triggering immunogenic cell death in the tumor cells. Notwithstanding, PDT-driven oxygen consumption and microvascular damage can further aggravate hypoxia to exaggerates glycolysis, leading to lactate accumulation and immunosuppressive tumor microenvironment. Herein, a supramolecular prodrug nanoplatform codelivering a photosensitizer and a prodrug of bromodomain-containing protein 4 inhibitor (BRD4i) JQ1 for combinatory photoimmunotherapy of pancreatic cancer are demonstrated. The nanoparticles are fabricated by host-guest complexation between cyclodextrin-grafted hyaluronic acid (HA-CD) and adamantine-conjugated heterodimers of pyropheophorbide a (PPa) and JQ1, respectively. HA can achieve active tumor targeting by recognizing highly expressed CD44 on the surface of pancreatic tumors. PPa-mediated PDT can enhance the immunogenicity of the tumor cells and promote intratumoral infiltration of the cytotoxic T lymphocytes. Meanwhile, JQ1 combats PDT-mediated immune evasion through inhibiting expression of c-Myc and PD-L1, which are key regulators of tumor glycolysis and immune evasion. Collectively, this study presents a novel strategy to enhance photoimmunotherapy of the pancreatic cancer by provoking T cells activation and overcoming adaptive immune resistance.

[Surgical treatment of primary liver cancer:a report of 10 966 cases]

Objective: To summarize the experience of surgical treatment of primary liver cancer. Methods: The clinical data of 10 966 surgically managed cases with primary liver cancer, from January 1986 to December 2019 at Hepatobiliary Center, the First Affiliated Hospital of Nanjing Medical University, were retrospectively analyzed. The life table method was used to calculate the survival rate and postoperative recurrence rate. Log-rank test was used to compare the survival process of different groups, and the Cox regression model was used for multivariate analysis. In addition, 2 884 cases of hepatocellular carcinoma(HCC) with more detailed follow-up data from 2009 to 2019 were selected for survival analysis. Among 2 549 patients treated with hepatectomy, there were 2 107 males and 442 females, with an age of (56.6±11.1) years (range: 20 to 86 years). Among 335 patients treated with liver transplantation, there were 292 males and 43 females, with an age of (51.0±9.7) years (range: 21 to 73 years). The outcomes of hepatectomy versus liver transplantation, anatomic versus non-anatomic hepatectomy were compared, respectively. Results: Of the 10 966 patients with primary liver cancer, 10 331 patients underwent hepatectomy and 635 patients underwent liver transplantation. Patients with liver resection were categorized into three groups: 1986－1995(712 cases), 1996－2008(3 988 cases), 2009‒2019(5 631 cases). The 5-year overall survival rate was 32.9% in the first group(1986－1995). The 5-year overall survival rate of resected primary liver cancer was 51.7% in the third group(2009-2019), among which the 5-year overal survival rates of hepatocellular carcinoma, intrahepatic cholangiocarcinoma and mixed liver cancer were 57.4%, 26.6% and 50.6%, respectively. Further analysis was performed on 2 549 HCC patients with primary hepatectomy. The 1-, 3-, 5-, and 10-year overall survival rates were 88.1%, 71.9%, 60.0%, and 41.0%, respectively, and the perioperative mortality rate was 1.0%. Two hundred and forty-seven HCC patients underwent primary liver transplantation, with 1-, 3-, 5-, and 10-year overall survival rates of 84.0%, 64.8%, 61.9%, and 57.6%, respectively. Eighty-eight HCC patients underwent salvage liver transplantation, with the 1-, 3-, 5-, and 10-year overall survival rates of 86.8%, 65.2%, 52.5%, and 52.5%, respectively. There was no significant difference in survival rates between the two groups with liver transplantation (P>0.05). Comparing the overall survival rates and recurrence rates of primary hepatectomy (2 549 cases) with primary liver transplantation (247 cases), the 1-, 3-, 5-, and 10-year overall survival rates in patients within Milan criteria treated with hepatectomy and transplantation were 96.3%, 87.1%, 76.9%, 54.7%, and 95.4%, 79.4%, 77.4%, 71.7%, respectively (P=0.754). The 1-, 3-, 5-year recurrence rates were 16.3%, 35.9%, 47.6% and 8.1%, 11.7%, 13.9%, respectively(P<0.01). The 1-, 3-, 5-, 10-year overall survival rates in patients with no large vessels invasion beyond the Milan criteria treated with liver resection and transplantation were 87.2%, 65.9%, 53.0%, 33.0% and 87.6%, 71.8%, 71.8%, 69.3%, respectively(P=0.003); the 1-, 3-, 5-year recurrence rate were 39.2%, 57.8%, 69.7% and 29.7%, 36.7%, 36.7%, respectively (P<0.01). The 1-, 3-, 5-, and 10-year overall survival rates in patients with large vessels invasion treated with liver resection and transplantation were 62.1%, 36.1%, 22.2%, 15.0% and 62.9%, 31.8%,19.9%, 0, respectively (P=0.387); the 1-, 3-, 5-year recurrence rates were 61.5%, 74.7%, 80.8% and 59.7%, 82.9%, 87.2%, respectively(P=0.909). Independent prognostic factors for both overall survival and recurrence-free survival rates of HCC patients treated with liver resection included gender, neoadjuvant therapy, symptoms, AST, intraoperative or postoperative blood transfusion, tumor number, tumor size, cirrhosis, macrovascular invasion, microvascular invasion, and pathological differentiation. Propensity score matching analysis of 443 pairs further showed that there was no significant difference in overall survival rate between anatomical liver resection and non-anatomical liver resection(P=0.895), but the recurrence rate of non-anatomical liver resection was higher than that of anatomical liver resection(P=0.035). Conclusions: In the past decade, the overall survival rate of HCC undergoing surgical treatment is significantly higher than before. For HCC patients with good liver function reservation, surgical resection can be performed first, and salvage liver transplantation can be performed after recurrence. The effect of salvage liver transplantation is comparable to that of primary liver transplantation. As for the choice of liver resection approaches, non-anatomical resection can reserve more liver tissue and can be selected as long as the negative margin is guaranteed.

[Application of clip remodeling technique in microsurgical treatment of intracranial aneurysms via keyhole approaches]

Objective: To discuss the value and technique of clip remodeling in microsurgical treatment of intracranial aneurysms via keyhole approaches. Methods: The clinical data of patients with intracranial aneurysms, who were treated by microsurgical clipping via keyhole approaches from January 2017 to December 2019, were retrospectively analyzed. The clips were remodeled based on the aneurysmal characteristics during the procedure in 27 cases. Angiography was obtained within one week after surgery in order to evaluate the position of clips and the security of lesions. All patients were followed up at the outpatient clinic to assess the clinical outcomes. Results: A total of 27 patients harbored 30 intracranial aneurysms, including 23 ruptured lesions and 7 unruptured ones. There were 9 middle cerebral artery aneurysms, 11 anterior communicating artery aneurysms, 9 posterior communicating artery aneurysms and 1 anterior cerebral artery aneurysm, respectively. Nine patients were operated via supraorbital keyhole approach, as well as 17 via pterional keyhole approach and one via hemispheric keyhole approach. Postoperative angiography revealed complete obliteration of lesions without residual filling in all cases. Twenty-five patients recovered well at discharge and two presented with mild disability. After 3-36 months of follow-up, no rebleeding and new-onset neurological deficits were noted. Conclusion: Clip remodeling technique is a simple and effective option, which can alleviate the limitation of manipulative freedom under keyhole approaches and improve the microsurgical effect of intracranial aneurysms.

[Prevalence of diabetes and associated factors in Hainan centenarians]

Objective: To investigate basic characteristics of diabetes prevalence and associated factors in centenarians in Hainan province of China. Methods: All the subjects were from China Hainan Centenarian Cohort Study. A total of 1 002 centenarians were included in the final analysis, who were divided into three groups: diabetes group, impaired fasting glucose (IFG) group, and normal glucose group according to the guideline. Results: The average age of centenarians was (102.77±2.55) years, and the proportion of females was 82.0%. There were 95 centenarians who suffered from diabetes, and the prevalence rate was 9.5%. There were 81 centenarians who had IFG, and the prevalence rate was 8.1%. The mean fasting plasma glucose (FPG) level of centenarians was (5.12±1.44) mmol/L, while 43.5% of centenarians had FPG levels ranging from 4.00 to 5.00 mmol/L and 22.1% of centenarians had the FPG levels ranging from 5.00 to 6.00 mmol/L. Increased triglyceride level and abdominal obesity might be associated with the risk for diabetes. Conclusion: The glycometabolism in centenarians in Hainan was better than that in other age groups, and no gender specific difference was observed.

[Distribution characteristics of blood lipid profile in Hainan centenarians]

Objective: To explore the prevalence of lipid profile and the influencing factors of dyslipidemia in centenarians in Hainan province, and provide basic data for the study of the lipid profile in centenarians. Methods: The data of this study were from the baseline data of China Hainan Centenarian Cohort Study from June 2014 to December 2016. A total of 1 002 centenarians were recruited. According to the guidelines for the prevention and treatment of dyslipidemia in Chinese adults in 2016, the prevalence of lipid profile were described and the prevalence of dyslipidemia with different clinical classifications were compared, and the main influencing factors were analyzed. Results: The median levels of TC, TG, LDL-C and HDL-C were 4.60 mmol/L, 1.05 mmol/L, 2.77 mmol/L and 1.41 mmol/L, respectively, in centenarians in Hainan. Blood lipid profile level was higher in females than in males. With the increase of BMI, TC, TG and LDL-C increased significantly, while HDL-C decreased significantly. The total prevalence of dyslipidemia was 19.1%. Smoking, BMI and area distribution were the main influencing factors of dyslipidemia. Conclusion: The prevalence of dyslipidemia in centenarians in Hainan was at a low level compared with other countries, and the blood lipid profile level was higher in females than in males.

Ultra-low-dose CT reconstructed with ASiR-V using SmartmA for pulmonary nodule detection and Lung-RADS classifications compared with low-dose CT

AIM

To evaluate the accuracy of ultra-low-dose computed tomography (ULDCT) with ASiR-V using a noise index (SmartmA) for pulmonary nodule detection and Lung CT Screening Reporting And Data System (Lung-RADS) classifications compared with low-dose CT (LDCT).

MATERIALS AND METHODS

Two-hundred and ten patients referred for lung cancer screening underwent conventional chest LDCT (0.80 ± 0.28 mSv) followed immediately by ULDCT (0.16 ± 0.03 mSv). ULDCT was scanned using 120 kV/SmartmA with a noise index of 28 HU and reconstructed with ASiR-V70%. The types and diameters of all nodules were recorded. The attenuation of pure ground-glass nodules (pGGNs) was measured on LDCT. All nodules were further classified using Lung-RADS. Sensitivities of nodule detection on ULDCT were analysed using LDCT as the reference standard. Logistic regression was used to establish a prediction model for the sensitivity of nodules.

RESULTS

LDCT revealed 362 nodules and the overall sensitivity on ULDCT was 90.1%. The sensitivity for solid nodules (SNs) of ≥1 mm diameter was 96.6% (228/236) and 100% (26/26) for SNs of ≥6 mm diameter. For pGGNs of ≥6 mm, the overall sensitivity was 93% (40/43) and 100% (29/29) for nodules with a attenuation value -700 HU or more. The agreement of Lung-RADS classification between two scans was good. On logistic regression, diameter was the only independent predictor for sensitivity of SNs (p<0.05). Diameter and attenuation value were predictors for pGGNs (p<0.05).

CONCLUSION

ULDCT with ASiR-V using SmartmA is suitable for lung-cancer screening in people with a BMI ≤35 kg/m² as it has a low radiation dose of 0.16 mSv, high sensitivity for nodule detection and good performance of Lung-RADS classifications.

Altered Expression of GJD2 Messenger RNA and the Coded Protein Connexin 36 in Negative Lens-induced Myopia of Guinea Pigs

SIGNIFICANCE

Decreased expression of the retinal GJD2 gene messenger RNA (mRNA) and connexin 36 (Cx36) protein in the guinea pig negative lens-induced myopia (LIM) model suggests their involvement in local retinal circuits regulating eye growth.

PURPOSE

Previous studies suggest that the GJD2 gene and Cx36 protein encoded by the GJD2 gene play important roles in retinal signaling pathways and eye development. The aim of this study was to investigate the changes in GJD2 mRNA and Cx36 protein expression in the guinea pig lens-induced myopia model.

METHODS

Four-week-old guinea pigs were randomly divided into two groups. Animals in the experimental group were fitted with monocular -10 D lenses; and animals in the control group, with monocular plano lenses. Biometric measurements, including the spherical equivalent refractive error and axial length, were monitored. Animals were killed after 0, 1, 2, and 3 weeks of treatment, and their retinas were isolated. Retinal GJD2 mRNA and Cx36 protein expression levels were assessed by quantitative real-time polymerase chain reaction and Western blot analysis, respectively.

RESULTS

Spherical equivalent refractive error values indicated that negative lens-treated eyes became significantly more myopic than plano lens-treated eyes (P = .001), consistent with their longer axial lengths compared with those of control eyes. Both GJD2 mRNA and Cx36 protein expression levels were decreased in the retinas of negative lens-treated eyes compared with levels in the retinas of plano lens-treated eyes, although there were differences in the timing; GJD2 mRNA, levels were significantly decreased after 1 and 2 weeks of treatment (P = .01 and P = .004, respectively), whereas Cx36 protein expression was significantly decreased after only 1 week (P = .01).

CONCLUSIONS

That both retinal GJD2 mRNA and Cx36 protein expression levels were decreased after induction of myopia with negative lenses points to retinal circuits involving Cx36 in myopia development in the guinea pig.

Construction of SNP-STR Multiplex Amplification System with Genetic Markers and Its Forensic Application

Abstract

Objective To select and develop a SNP-STR multiplex amplification system with genetic markers compatible with current STR databases. To understand its genetic polymorphisms in Sichuan Han population and its application value in DNA mixture analysis. Methods Based on the STR genetic markers in commercial kits, SNPs adjacent to these STR markers were selected to be SNP-STR genetic markers. A SNP-STR multiplex amplification system with genetic markers based on allele-specific amplification was constructed using allele-specific amplification primers. The genetic polymorphism of the system in the Sichuan Han population was investigated and the efficiency of systems with different numbers of loci to detect the two individual DNA mixture samples was evaluated. Results An allele-specific multiplex amplification system constituted of 13 SNP-STR genetic markers was selected and constructed. In Sichuan Han population, the heterozygosity of each locus ranged from 0.76 to 0.88, and the combined discrimination power reached 0.999 999 999 999 999 968. In the analysis of the two individual DNA mixture samples： for single-locus amplification, the genotype of the minor components can still be detected when the mixture ratio reaches 1 000∶1; for multiple loci multiplex amplification, the maximum mixture ratio can reach 500∶1. As the number of loci in the system increased, the detection efficiency of the minor components in the DNA mixture decreased. Conclusion SNP-STR genetic markers have a higher polymorphism than STR. The multiplex amplification system made of SNP-STR genetic markers has a better analysis efficiency for mixed samples than traditional STR multiplex amplification system.

Role of PD-L1 in heart transplant rejection

Background

Acute cellular rejection remains a major cause of morbidity after heart transplantation with up to 30% of patients experiencing at least one rejection episode during the first year. Unfortunately, the mechanism underling rejection remains poorly understood and the gold standard for diagnosing rejection remains frequent cardiac biopsy for rejection surveillance – a process that is both invasive and costly.

Purpose

PD-L1 is a co-inhibitory transmembrane protein that interacts with PD-1 on T cells to inhibit T cell activation. Endothelial PD-L1 expression in the heart has been shown in mouse models to play a key role in attenuating immune-mediated cardiac disease like myocarditis. Recent data that anti-PD-1 and anti-PD-L1 therapy can lead to myocarditis further supports a role for PD-1/PD-L1 signaling in cardiovascular homeostasis. We hypothesize that PD-L1 expression correlates with rejection severity.

Methods

Endomyocardial biopsy from a cohort of 19 heart transplant patients were analyzed for PD-L1 expression using immunohistochemistry and image analysis with HALO software. Each patient had biopsies corresponding to 0R, 1R, and 2R grades of rejection (n=57) and thus each patient served as their own internal control. Detailed clinical data was also collected on these patients from the electronic medical record.

Results

Average PD-L1 levels associated with 0R (n=19), 1R (n=21), and 2R (n=17) rejection were 1.54, 9.15, and 18.90 respectively (P&lt;0.001). In patients who were treated for 2R rejection with increased immunosuppression (n=9), PD-L1 levels decreased from an average of 21.72 before treatment to an average of 5.64 after treatment (P&lt;0.05). A multiple regression was run to see if PD-L1 level was associated with right heart pressures, EKG intervals, echo data, or common lab values. Accounting for age, race, and sex, it was found that PD-L1 was significantly associated with PA pressure (P&lt;0.01, beta = 0.45), PCW pressure (P&lt;0.01, beta = 0.42), and BNP (P&lt;0.01, beta = 0.55).

Conclusions

Upregulation of PD-L1 in the heart is strongly associated with severity of cellular rejection after heart transplantation. Successful treatment of rejection with immunosuppression decreases PD-L1 levels. These data suggest that PD-L1 is a potential biomarker for heart transplant rejection. Further correlation of PD-L1 levels with signs of right heart strain (increased PA and PCW pressure) and systolic dysfunction (BNP) supports a clinical picture of PD-L1 as a useful biomarker for detecting both cellular rejection and reversal of rejection after treatment.

Cohort identification and results

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): National Institutes of Health grants R56 HL141466 and R01 HL141466

Silencing the long noncoding RNA NORAD inhibits gastric cancer cell proliferation and invasion by the RhoA/ROCK1 pathway

OBJECTIVE

The current study aimed to examine the role and mechanism of a conserved long noncoding RNA termed NORAD (noncoding RNA activated by DNA damage, also named LINC00657) in gastric cancer (GC) progression.

PATIENTS AND METHODS

Quantitative Real Time-Polymerase Chain Reaction (qRT-PCR) was used to determine the expression level of relevant genes in GC cell lines. Cell proliferation was examined by cell counting kit-8 (CCK-8) assays. Cell migration and invasion were detected by transwell migration and invasion assays. Protein levels of the indicated genes were detected by Western blotting. Cell apoptosis was examined by flow cytometry.

RESULTS

Results showed that NORAD knockdown decreased cell proliferation, migration and invasion but increased cell apoptosis. NORAD knockdown affected the expression of genes related to apoptosis and Epithelial-Mesenchymal Transition (EMT). In addition, NORAD's depletion resulted in reduced Ras Homolog Family Member A (RhoA) and Rho-associated coiled-coil containing protein kinase 1 (ROCK1) expression. Furthermore, NORAD's expression was positively correlated with RhoA and ROCK1 expressions in GC based on The Cancer Genome Atlas (TCGA) database.

CONCLUSIONS

Our results demonstrate the oncogenic role of NORAD in gastric cancer progression.

Repair of spinal cord injury in rats by umbilical cord mesenchymal stem cells through P38MAPK signaling pathway

OBJECTIVE

To explore the repair of spinal cord injury (SCI) in rats by umbilical cord mesenchymal stem cells (UCMSCs) through the p38mitogen-activated protein kinase (MAPK) signaling pathway.

MATERIALS AND METHODS

A total of 45 healthy adult male Sprague-Dawley rats weighing 180-220 g and aged 6-8 weeks old were randomly divided into group A (SCI model + transplantation of UCMSCs, n=15), group B (sham operation), and group C (SCI model + injection of an equal dose of DMEM, n=15) using a random number table. The morphology of spinal cord tissues was observed via hematoxylin-eosin (HE) staining, and the protein expression of phosphorylated p38 (p-p38) in spinal cord tissues, the expression of glial fibrillary acidic protein (GFAP) in the injury region, and the spinal cord neuronal apoptosis were detected via Western blotting, immunofluorescence labeling and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay, respectively.

RESULTS

In group B, there was no significant damage to the structure of spinal cord tissues. In group C, the spinal cord tissues had a disordered structure and significant fragmentation, the damage to grey matter was the greatest. Also, almost all of the grey matter was destroyed and dissolved, with a large number of scars and cavitation, and it was hard to distinguish the gray matter and white matter. In group A, the spinal cord tissues had a clear structure, there were smaller necrotic cavitation regions in the grey-white matter, and the number of cavitation significantly declined compared with that in group C. The results of immunofluorescence assay revealed that the expression of GFAP in spinal cord tissues was the lowest in group B, while it was remarkably decreased in group A compared with that in group C (p<0.05), suggesting that injecting UCMSCs via the caudal vein can prominently reduce the expression of GFAP in spinal cord tissues. Moreover, the spinal cord neuronal apoptosis rate was (4.21±0.19), (0.72±0.21) and (4.57±0.31), respectively, in group A, group B, and group C. It can be seen that the spinal cord neuronal apoptosis rate significantly declined in group A due to the treatment with UCMSCs. Also, the significant difference compared with that in group C, while it was significantly increased in group A compared with that in group B, but lower than group C (p<0.05). According to the results of Western blotting, the protein expression of p-p38 in spinal cord tissues was remarkably decreased in group B compared with that in group A and group C (p<0.05), while it was also markedly decreased in group A compared with that in group C (p<0.05), indicating that injecting UCMSCs via the caudal vein can significantly lower the protein expression of p-p38 in spinal cord tissues.

CONCLUSIONS

UCMSCs promote the recovery of neurological function, inhibit the p38 MAPK pathway activated after SCI, and reduce the spinal cord neuronal apoptosis in SCI rats.

Structure-Altering Mutations of the SARS-CoV-2 Frame Shifting RNA Element

With the rapid rate of Covid-19 infections and deaths, treatments and cures besides hand washing, social distancing, masks, isolation, and quarantines are urgently needed. The treatments and vaccines rely on the basic biophysics of the complex viral apparatus. While proteins are serving as main drug and vaccine targets, therapeutic approaches targeting the 30,000 nucleotide RNA viral genome form important complementary approaches. Indeed, the high conservation of the viral genome, its close evolutionary relationship to other viruses, and the rise of gene editing and RNA-based vaccines all argue for a focus on the RNA agent itself. One of the key steps in the viral replication cycle inside host cells is the ribosomal frameshifting required for translation of overlapping open reading frames. The frameshifting element (FSE), one of three highly conserved regions of coronaviruses, includes an RNA pseudoknot considered essential for this ribosomal switching. In this work, we apply our graph-theory-based framework for representing RNA secondary structures, "RAG" (RNA-As Graphs), to alter key structural features of the FSE of the SARS-CoV-2 virus. Specifically, using RAG machinery of genetic algorithms for inverse folding adapted for RNA structures with pseudoknots, we computationally predict minimal mutations that destroy a structurally-important stem and/or the pseudoknot of the FSE, potentially dismantling the virus against translation of the polyproteins. Additionally, our microsecond molecular dynamics simulations of mutant structures indicate relatively stable secondary structures. These findings not only advance our computational design of RNAs containing pseudoknots; they pinpoint to key residues of the SARS-CoV-2 virus as targets for anti-viral drugs and gene editing approaches.

[Clinical characteristics and outcome of 64 patients with severe COVID-19]

Objective: To investigate the causes of death in patients with severe COVID-19. Methods: A retrospective analysis was performed on 64 patients with severe COVID-19 admitted to Wuhan Pulmonary Hospital from January 12, 2020 to February 28, 2020. There were 36 males and 28 females, aging from 44 to 85 years[median 68 (62, 72)]. Fifty-two patients (81%) had underlying comorbidities. The patients were divided into the death group (n=40) and the survival group (n=24) according to the treatment outcomes. In the death group, 24 were male, and 16 were female, aging from 49 to 85 years [median 69 (62, 72)], with 31 cases (78%) complicated with underlying diseases. In the survival group, there were 12 males and 12 females, aging from 44 to 82 years[median 66 (61,73)], with 21 cases (88%) with comorbidities. Clinical data of the two groups were collected and compared, including general information, laboratory examinations, imaging features and treatments. For normally distributed data, independent group t test was used; otherwise, Mann Whitney test was used to compare the variables. χ(2) test and Fisher exact test was used when analyzing categorical variables. Results: The median of creatine kinase isozyme (CK-MB) in the death group was 19.0 (17.0,23.0) U/L, which was higher than that in the survival group 16.5 (13.5,19.6) U/L. The median level of cTnI in the death group was 0.03 (0.03, 0.07) μg/L, which was significantly higher than that in the survival group (0.02, 0.03) μg/L, with a statistically significant difference between the two groups (P=0.007). The concentration of myoglobin in the death group was 79.5 (28.7, 189.0) μg/L, which was higher than 33.1 (25.7, 54.5) μg/L in the survival group. The level of D-dimer in the death group was 2.0 (0.6, 5.2) mg/L, which was higher than 0.7 (0.4, 2.0) mg/L in the survival group. The LDH level of the death group was 465.0 (337.5,606.5) U/L, which was higher than that of the survibal group, 341.0 (284.0,430.0) U/L, the difference being statistically significant (P=0.006). The concentration of alanine aminotransferase in the death group was 40.0 (30.0, 48.0) U/L, which was higher than 32.5 (24.0, 40.8) U/L in the survival group, and the difference was statistically significant (P=0.047).Abnormal ECG was found in 16 cases (62%) in the death group, which was significantly higher than that in the survival group (29%), the difference being statistically significant (P=0.024) .The main causes of death were severe pneumonia with acute respiratory distress syndrome (ARDS, n=20), acute heart failure(n=9), atrial fibrillation(n=3) and multiple organ dysfunction syndrome (MODS, n=3). Conclusions: ARDS caused by severe pneumonia and acute heart failure and atrial fibrillation caused by acute viral myocarditis were the main causes of death in severe COVID-19 patients. Early prevention of myocardial injury and treatment of acute viral myocarditis complicated with disease progression may provide insights into treatment and reduction of mortality in patients with severe COVID-19.