DNA-PKcs/AKT1 inhibits epithelial-mesenchymal transition during radiation-induced pulmonary fibrosis by inducing ubiquitination and degradation of Twist1.

INTRODUCTION: Radiation-induced pulmonary fibrosis (RIPF) is a chronic, progressive, irreversible lung interstitial disease that develops after radiotherapy. Although several previous studies have focused on the mechanism of epithelial-mesenchymal transition (EMT) in lung epithelial cells, the essential factors involved in this process remain poorly understood. The DNA-dependent protein kinase catalytic subunit (DNA-PKcs) exhibits strong repair capacity when cells undergo radiation-induced damage; whether DNA-PKcs regulates EMT during RIPF remains unclear. OBJECTIVES: To investigate the role and molecular mechanism of DNA-PKcs in RIPF and provide an important theoretical basis for utilising DNA-PKcs-targeted drugs for preventing RIPF. METHODS: DNA-PKcs knockout (DPK-/-) mice were generated via the Cas9/sgRNA technique and subjected to whole chest ionizing radiation (IR) at a 20 Gy dose. Before whole chest IR, the mice were intragastrically administered the DNA-PKcs-targeted drug VND3207. Lung tissues were collected at 1 and 5 months after IR. RESULTS: The expression of DNA-PKcs is low in pulmonary fibrosis (PF) patients. DNA-PKcs deficiency significantly exacerbated RIPF by promoting EMT in lung epithelial cells. Mechanistically, DNA-PKcs deletion by shRNA or inhibitor NU7441 maintained the protein stability of Twist1. Furthermore, AKT1 mediated the interaction between DNA-PKcs and Twist1. High Twist1 expression and EMT-associated changes caused by DNA-PKcs deletion were blocked by insulin-like growth factor-1 (IGF-1), an AKT1 agonist. The radioprotective drug VND3207 prevented IR-induced EMT and alleviated RIPF in mice by stimulating the kinase activity of DNA-PKcs. CONCLUSION: Our study clarified the critical role and mechanism of DNA-PKcs in RIPF and showed that it could be a potential target for preventing RIPF.

Blockade of BLyS inhibits B-cell responses and antibody production for the prevention of chronic transplant rejection.

BACKGROUND: Chronic rejection, closely related to the activation of B cells and donor-specific antibody (DSA) production, has unsatisfactory therapeutic outcomes. B lymphocyte stimulator (BLyS) is a major regulatory factor that controls the activation and differentiation of B cells. However, it remains unclear whether BLyS blockade can regulate B and plasma cells in the transplantation setting and affect chronic rejection. Here, we investigated the efficacy of the BLyS inhibitors belimumab and telitacicept in controlling B-cell response and preventing chronic rejection. METHODS: The effects of belimumab and telitacicept on B-cell activation, differentiation, and antibody production in vitro were determined. A chronic rejection model in mouse was established by allogeneic cardiac transplantation with CTLA4-Ig treatment. Allograft survival, histology, DSA levels, and B-cell responses were analyzed to evaluate the chronic rejection-preventive effects of belimumab and telitacicept. RESULTS: In vitro experiments confirmed that belimumab and telitacicept inhibited B-cell activation and differentiation and reduced antibody production. In vivo experiments indicated that they significantly prolonged allograft survival, attenuated chronic rejection through significant suppression of myocardial ischemic necrosis and interstitial fibrosis, and reduced DSA-IgG levels, C4d deposition, and inflammatory cell infiltration. Furthermore, the frequencies of B cells, plasma cells, and IgG-producing cells in the recipients' spleen, lymph nodes, bone marrow, and blood were decreased after BLyS inhibitors treatment. CONCLUSIONS: This study demonstrated that belimumab and telitacicept inhibit B-cell responses and antibody production and alleviate chronic transplant rejection. Therefore, BLyS inhibitors are expected to be used for the prevention of chronic rejection in clinical practice.

Therapeutic strategies against BK polyomavirus infection in kidney transplant recipients: Systematic review and meta-analysis.

BACKGROUND: The selection of antiviral therapy for BK polyomavirus (BKPyV) infection has been extensively debated. Our study aimed to assess the efficacy and safety of various treatments for BKPyV infection. METHODS: We searched PubMed, EMBASE, and Web of Science databases for relevant studies regarding drug treatments for BKPyV viremia/DNAemia published between January 1, 1970 and September 30, 2022. Two independent authors screened the published studies, extracted pertinent data, and evaluated their methodological quality. A meta-analysis was performed using the RevMan software version 4.2.2. RESULTS: A total of 33 published studies involving 986 patients were included in the meta-analysis. Overall, therapeutic interventions comprised immunosuppression reduction alone or in combination with leflunomide, intravenous immunoglobulin (IVIG), cidofovir, or mTOR inhibitor (mTORi) therapy. The meta-analysis revealed that the efficacy of immunosuppression reduction alone for serum BKPyV clearance was 68% (95% confidence interval [CI]: 0.58-0.77; I2 = 78%). Moreover, the efficacy of immunosuppression reduction in combination with leflunomide, cidofovir, IVIG, or mTORi therapy for serum BKPyV clearance was 61% (95% CI: 0.47-0.74; I2 = 83%), 71% (95% CI: 0.63-0.78; I2 = 0), 87% (95% CI: 0.82-0.93; I2 = 45%), and 80% (95% CI: 0.59-1.00; I2 = 58%), respectively. Compared to immunosuppression reduction alone, immunosuppression reduction combined with IVIG therapy offered a statistically significant benefit in serum BKPyV clearance (P < 0.01) with minimal adverse reactions, whereas other adjunctive drug treatments did not demonstrate considerable effects. CONCLUSIONS: Reducing immunosuppression remains the primary approach for treating BKPyV infection. Although the combination treatment with IVIG proved to be most effective, other agents might offer varied antiviral advantages of high heterogeneity, which should be substantiated in future long-term randomized controlled trials.

Corrigendum: Dynamic risk prediction of BK polyomavirus reactivation after renal transplantation.

[This corrects the article DOI: 10.3389/fimmu.2022.971531.].

Deficiency of salt-inducible kinase 2 (SIK2) promotes immune injury by inhibiting the maturation of lymphocytes.

Salt-inducible kinase 2 (SIK2) belongs to the serine/threonine protein kinases of the AMPK/SNF1 family, which has important roles in cell cycle, tumor, melanogenesis, neuronal damage repair and apoptosis. Recent studies showed that SIK2 regulates the macrophage polarization to make a balance between inflammation and macrophage. Macrophage is critical to initiate immune regulation, however, whether SIK2 can be involved in immune regulation is not still well understood. Here, we revealed that the protein of SIK2 was highly expressed in thymus, spleen, lung, and brain. And SIK2 protein content increased in RAW264.7 and AHH1 cells with a time and dose-dependent after-ionizing radiation (IR). Inhibition of SIK2 could promote AHH1 cells apoptosis Moreover, we used the Cre-LoxP system to construct the SIK2+/- mice, and the research on function suggested that the deficiency of SIK2 could promote the sensitivity of IR. The deficiency of SIK2 promoted the immune injury via inhibiting the maturation of T cells and B cells. Furthermore, the TCRß rearrangement was inhibited by the deficiency of SIK2. Collectively, this study demonstrated that SIK2 provides an essential function of regulating immune injury, which will provide new ideas for the treatment of immune injury-related diseases.

Fatal BK polyomavirus-associated pneumonia: report of two cases with literature review.

BACKGROUND: In immunocompromised populations, such as patients with AIDS and recipients of solid organ and hematopoietic stem cell transplants, BK polyomavirus (BKPyV) can reactivate and cause several diseases, which can lead to death in their severe forms. Unlike hemorrhagic cystitis and BKPyV-associated nephropathy, BKPyV-associated pneumonia is rare, with only seven known cases worldwide. However, the disease can rapidly progress with extremely high mortality. CASE PRESENTATION: Herein, we report two cases of BKPyV-associated pneumonia following hematopoietic stem cell transplantation. Both patients had consistent infectious pneumonia and graft-versus-host disease after stem cell transplantation. The diagnosis of BKPyV-associated pneumonia was confirmed by metagenomic next-generation sequencing and polymerase chain reaction after the sudden worsening of the pulmonary infection signs and symptoms concomitant with renal dysfunction and systemic immune weakening. Both patients eventually died of systemic multi-organ failure caused by severe pneumonia. CONCLUSIONS: Currently, BKPyV reactivation cannot be effectively prevented. Immunocompromised patients must actively manage their primary lung infections, pay close attention to pulmonary signs and imaging changes. Especially during and after steroid pulse therapy or immunosuppressive therapy for graft versus host diseases, BKPyV load in blood/urine needs to be regularly measured, and the immunosuppressive intensity should be adjusted properly after the BKPyV reactivation diagnosis. Clinical trials of new antiviral drugs and therapies for BKPyV are urgently needed.

Microbiota of long-term indwelling hemodialysis catheters during renal transplantation perioperative period: a cross-sectional metagenomic microbial community analysis.

Background: Catheter-related infection (CRI) is a major complication in patients undergoing hemodialysis. The lack of high-throughput research on catheter-related microbiota makes it difficult to predict the occurrence of CRI. Thus, this study aimed to delineate the microbial structure and diversity landscape of hemodialysis catheter tips among patients during the perioperative period of kidney transplantation (KTx) and provide insights into predicting the occurrence of CRI.Methods: Forty patients at the Department of Transplantation undergoing hemodialysis catheter removal were prospectively included. Samples, including catheter tip, catheter outlet skin swab, catheter blood, peripheral blood, oropharynx swab, and midstream urine, from the separate pre- and post-KTx groups were collected and analyzed using metagenomic next-generation sequencing (mNGS). All the catheter tips and blood samples were cultured conventionally.Results: The positive detection rates for bacteria using mNGS and traditional culture were 97.09% (200/206) and 2.65% (3/113), respectively. Low antibiotic-sensitivity biofilms with colonized bacteria were detected at the catheter tip. In asymptomatic patients, no statistically significant difference was observed in the catheter tip microbial composition and diversity between the pre- and post-KTx group. The catheter tip microbial composition and diversity were associated with fasting blood glucose levels. Microorganisms at the catheter tip most likely originated from catheter outlet skin and peripheral blood.Conclusions: The long-term colonization microbiota at the catheter tip is in a relatively stable state and is not readily influenced by KTx. It does not act as the source of infection in all CRIs, but could reflect hematogenous infection to some extent.

Clinical features of Talaromyces marneffei infection in HIV-positive and HIV-negative individuals: A retrospective study in southern China.

Talaromyces marneffei (TSM) is a temperature-dependent dimorphic fungus endemic to Southeast Asia and southern China. As the number of people at risk of TSM infection continues to increase, the clinical manifestations are becoming increasingly complex, posing challenges for clinical management. In this study, we analyzed the medical records of 99 patients (71 human immunodeficiency virus [HIV]-positive and 28 HIV-negative) diagnosed with TSM infection from January 1, 2017, to December 31, 2022, in southern China and compared the clinical manifestations in HIV-positive and HIV-negative patients. Most patients (83/99, 84%) were male. The incidence of skin and soft tissue involvement (48% vs. 21%, P = .016); disseminated infection with blood circulation, hematopoietic, lymphatic, alimentary, or central nervous system involvement (69% vs. 36%, P = .002); and gastrointestinal bleeding (33% vs. 9%, P = .023) was higher in the HIV-positive group than the HIV-negative group. The HIV-positive group also had significantly higher alanine aminotransferase (ALT) levels (31 [26-42] vs. 14 [11-16] U/l, P < .001) and ALT/aspartate transaminase ratio (1.9 [1.5-2.2] vs. 1.3 [1.1-1.6], P = .006) than the HIV-negative group. The time to diagnosis (5.5 ± 1.1 vs. 5.1 ± 1.4 days, P = .103), antifungal regimen (P = .278), case fatality rate (20% vs. 21%, P = .849), and relapse/reinfection rate (11% vs. 19%, P = .576) did not differ significantly between the HIV-positive and HIV-negative groups. Poor antiretroviral therapy adherence (OR = 26.19, 95%CI 3.26-210.70, P = .002), advanced age (OR = 1.13, 95%CI 1.03-1.23, P = .010), and Epstein-Barr virus co-infection (OR = 37.13, 95%CI 3.03-455.64, P = .005) were independent risk factors for all-cause mortality from TSM infection in HIV-positive patients. Overall, the predominant infection sites, clinical manifestations, and complications of TSM infection differed by HIV status. However, with prompt diagnosis and appropriate treatment, HIV-positive patients with TSM infection can have similar outcomes to HIV-negative patients.

There are certain differences in the clinical features, sites of infection, and associated complications of Talaromyces marneffei infection between individuals with and without human immunodeficiency virus. It is necessary to accurately identify individuals at high risk to enable prompt diagnosis and standardized treatment.

Dynamic viral integration patterns actively participate in the progression of BK polyomavirus-associated diseases after renal transplantation.

The classical lytic infection theory along with large T antigen-mediated oncogenesis cannot explain the BK polyomavirus (BKPyV)-associated tumor secondary to BKPyV-associated nephropathy (BKVAN), viremia/DNAemia, and viruria after renal transplantation. This study performed virome capture sequencing and pathological examination on regularly collected urine sediment and peripheral blood samples, and BKVAN and tumor biopsy tissues of 20 patients with BKPyV-associated diseases of different stages. In the early noncancerous stages, well-amplified integration sites were visualized by in situ polymerase chain reaction, simultaneously with BKPyV inclusion bodies and capsid protein expression. The integration intensity, the proportion of microhomology-mediated end-joining integration, and host PARP-1 and POLQ gene expression levels increased with disease progression. Furthermore, multiomics analysis was performed on BKPyV-associated urothelial carcinoma tissues, identifying tandem-like structures of BKPyV integration using long-read genome sequencing. The carcinogenicity of BKPyV integration was proven to disturb host gene expression and increase viral oncoprotein expression. Fallible DNA double-strand break repair pathways were significantly activated in the parenchyma of BKPyV-associated tumors. Olaparib showed an antitumor activity dose-response effect in the tumor organoids without BRCA1/2 genes mutation. In conclusion, the dynamic viral integration patterns actively participate in the progression of BKPyV-associated diseases and thus could be a potential target for disease monitoring and intervention.

The Promising Therapeutic Approaches for Radiation-Induced Pulmonary Fibrosis: Targeting Radiation-Induced Mesenchymal Transition of Alveolar Type II Epithelial Cells.

Radiation-induced pulmonary fibrosis (RIPF) is a common consequence of radiation for thoracic tumors, and is accompanied by gradual and irreversible organ failure. This severely reduces the survival rate of cancer patients, due to the serious side effects and lack of clinically effective drugs and methods. Radiation-induced pulmonary fibrosis is a dynamic process involving many complicated and varied mechanisms, of which alveolar type II epithelial (AT2) cells are one of the primary target cells, and the epithelial-mesenchymal transition (EMT) of AT2 cells is very relevant in the clinical search for effective targets. Therefore, this review summarizes several important signaling pathways that can induce EMT in AT2 cells, and searches for molecular targets with potential effects on RIPF among them, in order to provide effective therapeutic tools for the clinical prevention and treatment of RIPF.

A single-center analysis of genotype-phenotype characteristics of Chinese patients with autosomal dominant polycystic kidney disease by targeted exome sequencing.

Background: Autosomal dominant polycystic kidney disease (ADPKD) is mainly caused by PKD1 and PKD2 mutations. However, only a few studies have investigated the genotype and phenotype characteristics of Asian patients with ADPKD. This study aimed to investigate the relationship between the natural course of ADPKD genotype and phenotype. Methods: Genetic studies of PKD1/2 genes of Chinese patients with ADPKD in a single center were performed using targeted exome sequencing and next-generation sequencing on peripheral blood DNA. Results: Among the 140 patients analyzed, 80.00% (n = 112) harbored PKD1 mutations, 11.43% (n = 16) harbored PKD2 mutations, and 8.57% (n = 12) harbored neither PKD1 nor PKD2 mutations. The average age at dialysis was 52.60 ± 11.36, 60.67 ± 5.64, and 52.11 ± 14.63 years, respectively. The renal survival rate of ADPKD patients with PKD1 mutations (77/112) was significantly lower than that of those with PKD2 mutations (9/16), leading to an earlier onset of end-stage renal disease (ESRD). Renal prognosis was poor for those with nonsense mutations, and they required earlier renal replacement therapy. Conclusions: The genotype and phenotype characteristics of ADPKD patients potentially vary across ethnic groups. Our findings supplement the genetic profiles of Chinese ADPKD patients, could serve as a guide for therapy monitoring and prognosis assessment of ADPKD, and may improve the clinical diagnosis.

Dynamic risk prediction of BK polyomavirus reactivation after renal transplantation.

Purpose: To construct a dynamic prediction model for BK polyomavirus (BKV) reactivation during the early period after renal transplantation and to provide a statistical basis for the identification of and intervention for high-risk populations. Methods: A retrospective study of 312 first renal allograft recipients with strictly punctual follow-ups was conducted between January 2015 and March 2022. The covariates were screened using univariable time-dependent Cox regression, and those with P<0.1 were included in the dynamic and static analyses. We constructed a prediction model for BKV reactivation from 2.5 to 8.5 months after renal transplantation using dynamic Cox regression based on the landmarking method and evaluated its performance using the area under the curve (AUC) value and Brier score. Monte-Carlo cross-validation was done to avoid overfitting. The above evaluation and validation process were repeated in the static model (Cox regression model) to compare the performance. Two patients were presented to illustrate the application of the dynamic model. Results: We constructed a dynamic prediction model with 18 covariates that could predict the probability of BKV reactivation from 2.5 to 8.5 months after renal transplantation. Elder age, basiliximab combined with cyclophosphamide for immune induction, acute graft rejection, higher body mass index, estimated glomerular filtration rate, urinary protein level, urinary leukocyte level, and blood neutrophil count were positively correlated with BKV reactivation, whereas male sex, higher serum albumin level, and platelet count served as protective factors. The AUC value and Brier score of the static model were 0.64 and 0.14, respectively, whereas those of the dynamic model were 0.79 ± 0.05 and 0.08 ± 0.01, respectively. In the cross-validation, the AUC values of the static and dynamic models decreased to 0.63 and 0.70 ± 0.03, respectively, whereas the Brier score changed to 0.11 and 0.09 ± 0.01, respectively. Conclusion: Dynamic Cox regression based on the landmarking method is effective in the assessment of the risk of BKV reactivation in the early period after renal transplantation and serves as a guide for clinical intervention.

Inhibition of lncRNA RET enhances radio-sensitivity of tumor cells via miR-3179/Slug/PTEN axis.

Radioresistance is one of the key obstacles that may lead to the failure of cancer treatment. The underlying mechanisms of radioresistance remain largely unknown; however, increasing evidence has shown that long noncoding RNAs (lncRNAs) are involved in radiotherapy resistance of several cancers. In the present study, we demonstrated that radiation-elevated transcript (RET), a newly identified lnRNA, was highly expressed in cancer cells. Knockdown of RET significantly inhibited the proliferation and colony formation of cancer cells and markedly inhibited apoptosis. Furthermore, downregulation of RET in cancer cells significantly inhibited cell growth, decreased colony survival fractions, and promoted apoptosis in response to radiation treatment, indicating a role in radiation resistance. Moreover, RET knockdown significantly increased the expression of γ-H2AX, an indicator of DNA double strand damage, and reversed radiation-induced EMT, both of which contributed to its radiation resistance. In addition, a negative correlation was found between the expression of RET and PTEN. Rescue assays confirmed RET knockdown enhanced radiosensitivity of cancer cells by upregulating the expression of PTEN. Mechanistically, RET positively regulated Slug, a repressor of PTEN transcription, by acting as a molecular sponge of miR-3179. Our present study showed that RET conferred radioresistance by regulating miR-3179/Slug/PTEN axis, indicating that RET may be a potential target for the clinical application in cancer patients with radioresistance.

Transcriptional inhibition of miR-486-3p by BCL6 upregulates Snail and induces epithelial-mesenchymal transition during radiation-induced pulmonary fibrosis.

BACKGROUND: Ionizing radiation (IR) can induce pulmonary fibrosis by causing epithelial mesenchymal transition (EMT), but the exact mechanism has not been elucidated. To investigate the molecular mechanism of how radiation induces pulmonary fibrosis by altering miR-486-3p content and thus inducing EMT. METHODS: The changes of miR-486-3p in cells after irradiation were detected by RT-qPCR. Western blot was used to detect the changes of cellular epithelial marker protein E-cadherin, mesenchymal marker N-cadherin, Vimentin and other proteins. The target gene of miR-486-3p was predicted by bioinformatics method and the binding site was verified by dual luciferase reporter system. In vivo experiments, adeno-associated virus (AAV) was used to carry miR-486-3p mimic to lung. Radiation-induced pulmonary fibrosis (RIPF) model was constructed by 25Gy60Co γ-rays. The structural changes of mouse lung were observed by HE and Masson staining. The expression of relevant proteins in mice was detected by immunohistochemistry. RESULTS: IR could decrease the miR-486-3p levels in vitro and in vivo, and that effect was closely correlated to the occurrence of RIPF. The expression of Snail, which induces EMT, was shown to be restrained by miR-486-3p. Therefore, knockdown of Snail blocked the EMT process induced by radiation or knockdown of miR-486-3p. In addition, the molecular mechanism underlying the IR-induced miRNA level reduction was explored. The increased in BCL6 could inhibit the formation of pri-miR-486-3p, thereby reducing the levels of miR-486-3p in the alveolar epithelial cells, which would otherwise promote EMT and contribute to RIPF by targeting Snail. CONCLUSION: IR can exacerbate RIPF in mice by activating the transcription factor BCL6, which inhibits the transcription of miR-486-3p and decreases its content, which in turn increases the content of the target gene slug and triggers EMT.

Acute transient thyroid swelling after fine-needle aspiration biopsy: A case report of a rare complication and a literature review.

Fine-needle aspiration biopsy (FNAB) is a safe and effective thyroid examination method with rare complications. Herein, we report a rare case of acute transient thyroid swelling that occurred after ultrasound-guided FNAB. The patient experienced acute pain with rapid thyroid swelling. Ultrasound imaging revealed a nodule with a linear, hypoechoic, and "patch-like" appearance, indicating edema without hemorrhage. After receiving anti-anaphylaxis and detumescence therapy for 1 day, the swelling regressed. Acute transient thyroid swelling is an extremely rare event that occurs shortly after FNAB and may frighten patients; therefore, clinicians should be aware of this complication in this context.

Combination of an Asphalt Stabilizer and a Cellulose-Chitosan Composite Aerogel Used for the Separation of Oil-Water Mixtures Containing Asphalt.

In this paper, cellulose chitosan composite aerogels were prepared through sol-gel and freeze-drying processes. The porous morphology of the aerogels was controlled by adjusting the cellulose concentration. Within a certain range, as the concentration of cellulose increases, the pore diameter of the composite aerogel becomes smaller and the pore structure becomes denser. The cellulose-chitosan composite aerogel can successfully separate the oil-water mixture without asphalt and showed stable filtration performance. The filtration speed is basically unchanged after a slight decrease and can be maintained at about 90% of the initial filtration speed within 30 min. The filtration speed can reach up to 9315 kg·h-1·m-2. When filtering bituminous oil-water mixtures, the filtration rate decreased significantly, with a 50% drop in 30 min. After adding the asphalt stabilizer poly(styrene-alt-octadecyl maleimide) (SNODMI), which is made in our laboratory, the effect of aerogel filtering the asphalt-containing oil-water mixture is obviously improved, and the downward trend of filtration speed is obviously improved. The combination of SNODMI and cellulose-chitosan has great application potential in the field of asphalt-containing oil-water separation.

Irradiation Activates MZF1 to Inhibit miR-541-5p Expression and Promote Epithelial-Mesenchymal Transition (EMT) in Radiation-Induced Pulmonary Fibrosis (RIPF) by Upregulating Slug.

Understanding miRNAs regulatory roles in epithelial-mesenchymal transition (EMT) would help establish new avenues for further uncovering the mechanisms underlying radiation-induced pulmonary fibrosis (RIPF) and identifying preventative and therapeutic targets. Here, we demonstrated that miR-541-5p repression by Myeloid Zinc Finger 1 (MZF1) promotes radiation-induced EMT and RIPF. Irradiation could decrease miR-541-5p expression in vitro and in vivo and inversely correlated to RIPF development. Ectopic miR-541-5p expression suppressed radiation-induced-EMT in vitro and in vivo. Knockdown of Slug, the functional target of miR-541-5p, inhibited EMT induction by irradiation. The upregulation of transcription factor MZF1 upon irradiation inhibited the expression of endogenous miR-541-5p and its primary precursor (pri-miR-541-5p), which regulated the effect of the Slug on the EMT process. Our finding showed that ectopic miR-541-5p expression mitigated RIPF in mice by targeting Slug. Thus, irradiation activates MZF1 to downregulate miR-541-5p in alveolar epithelial cells, promoting EMT and contributing to RIPF by targeting Slug. Our observation provides further understanding of the development of RIPF and determines potential preventative and therapeutic targets.

Heterogeneity of cell composition and origin identified by single-cell transcriptomics in renal cysts of patients with autosomal dominant polycystic kidney disease.

Rationale: Renal cysts in patients with autosomal dominant polycystic kidney disease (ADPKD) can originate from any nephron segments, including proximal tubules (PT), the loop of Henle (LOH), distal tubules (DT), and collecting ducts (CD). Previous studies mostly used limited cell markers and failed to identify cells negative for these markers. Therefore, the cell composition and origin of ADPKD cyst are still unclear, and mechanisms of cystogenesis of different origins await further exploration. Methods: We performed single-cell RNA sequencing for the normal kidney tissue and seven cysts derived from superficial or deep layers of the polycystic kidney from an ADPKD patient. Results: Twelve cell types were identified and analyzed. We found that a renal cyst could be derived either from CD or both PT and LOH. Gene set variation analysis (GSVA) showed that epithelial mesenchymal transition (EMT), TNFA signaling via the NFKB pathways, and xenobiotic metabolism were significantly activated in PT-derived cyst epithelial cells while robust expression of genes involved in G2M Checkpoint, mTORC1 signaling, E2F Targets, MYC Targets V1, MYC Targets V2 were observed in CD-derived cells. Conclusion: Our results revealed that a single cyst could originate from CD or both PT and LOH, suggesting heterogeneity of polycystic composition and origin. Furthermore, cyst epithelial cells with different origins have different gene set activation.