Single-cell transcriptome analysis of tumor and stromal compartments of pancreatic ductal adenocarcinoma primary tumors and metastatic lesions

BACKGROUND

Solid tumors such as pancreatic ductal adenocarcinoma (PDAC) comprise not just tumor cells but also a microenvironment with which the tumor cells constantly interact. Detailed characterization of the cellular composition of the tumor microenvironment is critical to the understanding of the disease and treatment of the patient. Single-cell transcriptomics has been used to study the cellular composition of different solid tumor types including PDAC. However, almost all of those studies used primary tumor tissues.

METHODS

In this study, we employed a single-cell RNA sequencing technology to profile the transcriptomes of individual cells from dissociated primary tumors or metastatic biopsies obtained from patients with PDAC. Unsupervised clustering analysis as well as a new supervised classification algorithm, SuperCT, was used to identify the different cell types within the tumor tissues. The expression signatures of the different cell types were then compared between primary tumors and metastatic biopsies. The expressions of the cell type-specific signature genes were also correlated with patient survival using public datasets.

RESULTS

Our single-cell RNA sequencing analysis revealed distinct cell types in primary and metastatic PDAC tissues including tumor cells, endothelial cells, cancer-associated fibroblasts (CAFs), and immune cells. The cancer cells showed high inter-patient heterogeneity, whereas the stromal cells were more homogenous across patients. Immune infiltration varies significantly from patient to patient with majority of the immune cells being macrophages and exhausted lymphocytes. We found that the tumor cellular composition was an important factor in defining the PDAC subtypes. Furthermore, the expression levels of cell type-specific markers for EMT+ cancer cells, activated CAFs, and endothelial cells significantly associated with patient survival.

CONCLUSIONS

Taken together, our work identifies significant heterogeneity in cellular compositions of PDAC tumors and between primary tumors and metastatic lesions. Furthermore, the cellular composition was an important factor in defining PDAC subtypes and significantly correlated with patient outcome. These findings provide valuable insights on the PDAC microenvironment and could potentially inform the management of PDAC patients.

Phenotype and molecular signature of CD8+ T cell subsets in T cell- mediated rejections after kidney transplantation

We investigated the phenotype and molecular signatures of CD8+ T cell subsets in kidney-transplant recipients (KTRs) with biopsy-proven T cell-mediated rejection (TCMR). We included 121 KTRs and divided them into three groups according to the pathologic or clinical diagnosis: Normal biopsy control (NC)(n = 32), TCMR (n = 50), and long-term graft survival (LTGS)(n = 39). We used flowcytometry and microarray to analyze the phenotype and molecular signatures of CD8+ T cell subsets using peripheral blood from those patients and analyzed significant gene expressions according to CD8+ T cell subsets. We investigated whether the analysis of CD8+ T cell subsets is useful for predicting the development of TCMR. CCR7+CD8+ T cells significantly decreased, but CD28nullCD57+CD8+ T cells and CCR7-CD45RA+CD8+ T cells showed an increase in the TCMR group compared to other groups (p<0.05 for each); hence CCR7+CD8+ T cells showed significant negative correlations to both effector CD8+ T cells. We identified genes significantly associated with the change of CCR7+CD8+ T, CCR7-CD45RA+CD8+ T, and CD28nullCD57+CD8+ T cells in an ex vivo study and found that most of them were included in the significant genes on in vitro CCR7+CD8+ T cells. Finally, the decrease of CCR7+CD8+ T cells relative to CD28nullCD57+ T or CCR7-CD45RA+CD8+ T cells can predict TCMR significantly in the whole clinical cohort. In conclusion, phenotype and molecular signature of CD8+ T subsets showed a significant relationship to the development of TCMR; hence monitoring of CD8+ T cell subsets may be a useful for predicting TCMR in KTRs.

Glutathione dynamics determine the therapeutic efficacy of mesenchymal stem cells for graft-versus-host disease via CREB1-NRF2 pathway

Glutathione (GSH), the most abundant nonprotein thiol functioning as an antioxidant, plays critical roles in maintaining the core functions of mesenchymal stem cells (MSCs), which are used as a cellular immunotherapy for graft-versus-host disease (GVHD). However, the role of GSH dynamics in MSCs remains elusive. Genome-wide gene expression profiling and high-throughput live-cell imaging assays revealed that CREB1 enforced the GSH-recovering capacity (GRC) of MSCs through NRF2 by directly up-regulating NRF2 target genes responsible for GSH synthesis and redox cycling. MSCs with enhanced GSH levels and GRC mediated by CREB1-NRF2 have improved self-renewal, migratory, anti-inflammatory, and T cell suppression capacities. Administration of MSCs overexpressing CREB1-NRF2 target genes alleviated GVHD in a humanized mouse model, resulting in improved survival, decreased weight loss, and reduced histopathologic damages in GVHD target organs. Collectively, these findings demonstrate the molecular and functional importance of the CREB1-NRF2 pathway in maintaining MSC GSH dynamics, determining therapeutic outcomes for GVHD treatment.

Phosphorylation of TFCP2L1 by CDK1 is required for stem cell pluripotency and bladder carcinogenesis

Molecular programs involved in embryogenesis are frequently upregulated in oncogenic dedifferentiation and metastasis. However, their precise roles and regulatory mechanisms remain elusive. Here, we showed that CDK1 phosphorylation of TFCP2L1, a pluripotency-associated transcription factor, orchestrated pluripotency and cell-cycling in embryonic stem cells (ESCs) and was aberrantly activated in aggressive bladder cancers (BCs). In murine ESCs, the protein interactome and transcription targets of Tfcp2l1 indicated its involvement in cell cycle regulation. Tfcp2l1 was phosphorylated at Thr177 by Cdk1, which affected ESC cell cycle progression, pluripotency, and differentiation. The CDK1-TFCP2L1 pathway was activated in human BC cells, stimulating their proliferation, self-renewal, and invasion. Lack of TFCP2L1 phosphorylation impaired the tumorigenic potency of BC cells in a xenograft model. In patients with BC, high co-expression of TFCP2L1 and CDK1 was associated with unfavorable clinical characteristics including tumor grade, lymphovascular and muscularis propria invasion, and distant metastasis and was an independent prognostic factor for cancer-specific survival. These findings demonstrate the molecular and clinical significance of CDK1-mediated TFCP2L1 phosphorylation in stem cell pluripotency and in the tumorigenic stemness features associated with BC progression.

Electroacupuncture to treat with Overactive Bladder in Postmenopausal Women: study protocol for a multicenter, randomized, controlled, parallel clinical trial

BACKGROUND

Electroacupuncture has been used for treatment in patients with overactive bladder. This study was conducted to evaluate the efficacy and safety of electroacupuncture for treating overactive bladder of postmenopausal women.

METHODS/DESIGN

This is a multicenter, randomized controlled, parallel clinical trial. Two hundred ninety participants with overactive bladder syndrome will be recruited from Dongguk University Bundang Oriental Hospital and Cheonan Korean Medicine Hospital of Daejeon University and randomly allocated into one of two groups in a 1:1 ratio. One group will receive electroacupuncture (EA) and the other acupuncture (AC). The allocation will be concealed from both participants and assessors. The study period will be about 10 weeks, including 6 weeks of electroacupuncture or acupuncture treatment and a four week follow-up period. Both EA group and AT group will undergo acupuncture at 7 fixed points, and the EA group will undergo electronic stimulation at 6 points. The primary outcome will be the average number of micturitions per 24 h based on a 3-day bladder diary. The secondary outcome will comprise the 3-day bladder diary, the overactive bladder symptom score and the results of the King's health questionnaire.

DISCUSSION

The results of this trial will provide information regarding the efficacy and safety of electroacupuncture for treating overactive bladder in postmenopausal women.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT03260907 . Registered on 24 August 2017.

Association between dry eye symptoms and suicidal ideation in a Korean adult population

Purpose

This study assessed the association of dry eyes with depression and suicidal ideation in a Korean adult population.

Methods

Data from 16408 participants (6972 men and 9436 women) aged ≥ 19 years included in the fifth Korea National Health and Nutrition Examination Survey, conducted from 2010–2012, were analyzed. For dry eyes, surveys of previous diagnosis of dry eye disease (DED) by an ophthalmologist and experience of subjective dry eye symptoms were separately used. Diagnosis of depression and suicidal ideation were obtained via responses to an interviewer-assisted questionnaire, and questions were asked in a closed-ended response format. Logistic regression was used to examine the associations between dry eyes, depression, and suicidal ideation.

Results

DED diagnosis exhibited an odds ratio (OR) of 1.32 (95% confidence interval [CI] 1.11–1.57) for depression and 1.24 (95% CI 1.05–1.48) for suicidal ideation compared to those without DED, after adjusting for sex, age, education, occupation, household income, body mass index, smoking behavior, alcohol consumption, physical activity, hypertension, diabetes, dyslipidemia, thyroid diseases, major cardiovascular disease, and cancer. Similarly, the adjusted OR (95% CI) of dry eye symptoms was 1.50 (95% CI 1.30–1.73) for depression and 1.47 (95% CI 1.27–1.70) for suicidal ideation.

Conclusion

Our findings suggest that dry eyes (either DED diagnosis or dry eye symptoms) may be associated with the prevalence of depression and suicidal ideation in the Korean adult population.

Urinary exosomal viral microRNA as a marker of BK virus nephropathy in kidney transplant recipients

Objective

Bkv-miR-B1-5p, one of the microRNAs encoded by BK virus, was recently reported to be elevated in the blood among the patients with BK virus nephropathy (BKVN). Urinary exosome was suggested to be a possible source of biomarker for kidney diseases, but it was unknown whether it could contain viral microRNA as well as human microRNAs. The aim of this study was to evaluate whether urinary exosomal BK viral microRNA were expressed during replication and could be used to diagnose BKVN in kidney transplant recipients.

Materials and methods

In a cross-sectional multicenter study, we collected and analyzed 458 graft biopsies from 385 kidney transplant recipients. Urine samples were collected at the time of graft biopsy, and microRNAs in urinary exosome were measured once. For 13 patients with BKVN and 67 age, sex-matched kidney transplant recipients, we measured BK viral microRNA B1-5p, 3p and human microRNA-16 in urinary exosomal fraction and compared the diagnostic value with BK viral load in plasma and urine.

Results

Pathology proven BKVN was diagnosed in 13 patients (2.8%). High levels of bkv-miR-B1-5p and bkv-miR-B1-3p were shown in all patients with BKVN. Meanwhile, plasma BK viral load assay (cut-off value of ≥ 4.0 log₁₀ copies/mL) showed false negative in 3 cases and urinary BK viral load assay (cut-off value of ≥ 7.0 log₁₀ copies/mL) showed false negative in 1 case among these 13 patients. The receiver operator characteristics curve analysis for bkv-miR-B1-5p and bkv-miR-B1-5p/miR-16 showed excellent discriminative power for the diagnosis of BKVN, with area under the curve values of 0.989 and 0.985, respectively.

Conclusions

This study suggests that urinary exosomal bkv-miR-B1-5p and bkv-miR-B1-5p/miR-16 could be surrogate markers for the diagnosis of BKVN.

Korean OBEsity Surgical Treatment Study (KOBESS): protocol of a prospective multicentre cohort study on obese patients undergoing laparoscopic sleeve gastrectomy and Roux-en-Y gastric bypass

INTRODUCTION

Bariatric surgery effectively induces long-term weight loss in Western populations. However, its effectiveness in Asians remains to be confirmed objectively. The Korean Society for Metabolic and Bariatric Surgery proposes the first prospective cohort study on Koreans undergoing bariatric surgery.

METHODS AND ANALYSIS

The Korean OBEsity Surgical treatment Study (KOBESS) is a prospective, multicentre, single-arm, observational, cohort study on morbidly obese patients who undergo primary sleeve gastrectomy or Roux-en-Y gastric bypass in Korea. In total, 100 consecutive obese Asian patients who will undergo bariatric surgery will be recruited in 2016-2017; follow-up will be for 1 year. Primary outcomes are change in body weight and waist circumference at 1 year. All patients will undergo anthropometry, laboratory tests, bioelectrical impedance analysis, gastrofibroscopy, polysomnography and fat-measuring CT before and after surgery. Patients with diabetes will also undergo perioperative oral glucose tolerance and endocrinological hormone tests. Hypertensive patients will also undergo perioperative echocardiography and carotid Doppler ultrasonography. Female patients suspected of having polycystic ovarian syndrome will also undergo perioperative hormone tests and abdominal ultrasonography. Visceral and subcutaneous fat will be harvested during surgery. Blood, stool and urine samples will be taken at various perioperative time points. Although the cohort is small and the follow-up duration is relatively short, this study will determine whether bariatric surgery induces satisfactory weight loss in obese Koreans. Significantly, the tissue samples will also facilitate many studies examining the effects of bariatric surgery and their mechanisms.

ETHICS AND DISSEMINATION

Ethics approval was obtained from the institutional review board of each participating hospital. All findings arising from this cohort study will be published in open-access peer-reviewed journals and will be presented at national and international meetings. All KOBESS investigators will be able to propose research studies and potential publications based on KOBESS data and tissue samples.

TRIAL REGISTRATION NUMBER

NCT03100292; Pre-results.