Biology subjects

Du, K.

Publications and source records attributed to Du, K..

59 records · Page 4Linked to original sources

bioRxiv2019

Inhibiting xCT/SLC7A11 induces ferroptosis of myofibroblastic hepatic stellate cells and protects against liver fibrosis

Background and AimsLiver fibrosis develops in the context of excessive oxidative stress, cell death and accumulation of myofibroblasts (MFs) derived from hepatic stellate cells (HSCs). Ferroptosis is a type of regulated cell death that can be caused by inhibiting the cystine/glutamate antiporter xCT. However, while xCT is induced in various liver diseases, its role in HSC activation and liver fibrosis is unknown. We hypothesized that xCT is required for HSCs to antagonize ferroptosis and remain myofibroblastic. MethodsxCT activity was disrupted by siRNA or pharmacological inhibitors in MF-HSC cell lines to determine its effect on redox homeostasis, growth, myofibroblastic activity and viability. xCT expression was then determined by RNA sequencing and RT-PCR during primary HSC activation, and its role in HSC trans-differentiation was assessed. For comparison, xCT expression and function were also determined in primary hepatocytes. Finally, the roles of xCT in HSC accumulation and liver fibrosis were assessed in mice treated acutely with CCl4. ResultsInhibiting xCT in MF-HSCs decreased intracellular glutathione (GSH), suppressed growth and fibrogenesis, and induced cell death. These effects were rescued by antioxidants, an iron chelator, and a canonical ferroptosis inhibitor, but not by inhibitors of apoptosis or necrosis. xCT was dramatically up-regulated during primary HSC activation, and inhibiting xCT suppressed myofibroblastic trans-differentiation and induced ferroptosis. In contrast, healthy hepatocytes were relatively insensitive to ferroptosis induced by xCT inhibition. In vivo, inhibiting xCT systemically reduced MF-HSC accumulation and liver fibrosis after a single dose of CCl4 without exacerbating liver injury or reducing hepatocyte regeneration. ConclusionCompared to healthy hepatocytes, MF-HSCs are exquisitely sensitive to ferroptosis induced by inhibiting xCT. In acutely injured livers, systemic inhibitors of xCT can inhibit fibrosis without worsening liver injury. Further research is needed to determine if this therapeutic window remains sufficiently robust to safely target MF-HSCs and inhibit fibrogenesis in chronically injured liver.

cell biology↗

bioRxiv2019

Natural hybridization reveals incompatible alleles that cause melanoma in swordtail fish

The establishment of reproductive barriers between populations is the key process that fuels the evolution of new species. A genetic framework for this process was proposed over 80 years ago, which posits "incompatible" interactions between genes that result in reduced survival or reproduction in hybrids. Despite this foundational work, progress has been slow in identifying individual genes that underlie hybrid incompatibilities, with only a handful known to date. Here, we use a combination of approaches to precisely map the genes that drive the development of a melanoma incompatibility in swordtail fish hybrids. We find that one of the genes involved in this incompatibility also causes melanoma in hybrids between distantly related species. Moreover, we show that this melanoma reduces survival in the wild, likely due to progressive degradation of the fin. Together, this work represents only the second case where the genes underlying a vertebrate hybrid incompatibility have been identified and provides the first glimpse into the action of these genes in natural hybrid populations. One sentence summaryUsing a combination of mapping approaches, we identify interacting genes that lead to melanoma in hybrids and characterize their effects in natural hybrid populations.

evolutionary biology↗

bioRxiv2019

High-throughput and all-solution phase African Swine Fever Virus (ASFV) detection using CRISPR-Cas12a and fluorescence based point-of-care system

Here we report the development of a high throughput, all-solution phase, and isothermal detection system to detect African Swine Fever Virus (ASFV). CRISPR-Cas12a programmed with a CRISPR RNA (crRNA) is used to detect ASFV target DNA. Upon ASFV DNA binding, the Cas12a/crRNA/ASFV DNA complex becomes activated and degrades a fluorescent single stranded DNA (ssDNA) reporter present in the assay. We combine this powerful CRISPR-Cas assay with fluorescence-based point-of-care (POC) system we developed for rapid and accurate virus detection. Without nucleic acid amplification, a detection limit of 1 pM is achieved within 2 hrs. In addition, the ternary Cas12a/crRNA/ASFV DNA complex is highly stable at physiological temperature and continues to cleave the ssDNA reporter even after 24 hrs of incubation, resulting in an improvement of the detection limit to 100 fM. We show that this system is very specific and can differentiate nucleic acid targets with closely matched sequences. The high sensitivity and selectivity of our system enables the detection of ASFV in femtomolar range. Importantly, this system features a disposable cartridge and a sensitive custom designed fluorometer, enabling compact, multiplexing, and simple ASFV detection, intended for low resource settings.

bioengineering↗

bioRxiv2019

Screening and identification of MicroRNAs expressed in perirenal adipose tissue during rabbit growth

MiRNAs regulate adipose tissue development, which are closely related to subcutaneous and intramuscular fat deposition and adipocyte differentiation. As an important economic and agricultural animal, rabbits have low adipose tissue deposition and are an ideal model to study adipose regulation. However, the miRNAs related to fat deposition during the growth and development of rabbits are poorly defined. In this study, miRNA-sequencing and bioinformatics analyses were used to profile the miRNAs in rabbit perirenal adipose tissue at 35, 85 and 120 days post-birth. Differentially expressed (DE) miRNAs between different stages were identified by DEseq in R. Target genes of DE miRNAs were predicted by TargetScan and miRanda. To explore the functions of identified miRNAs, Gene Ontology (GO) enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were performed. Approximately 1.6 GB of data was obtained by miRNA-seq. A total of 987 miRNAs (780 known and 207 newly predicted) and 174 DE miRNAs were identified. The miRNAs ranged from 18nt to 26nt. GO enrichment and KEGG pathway analyses revealed that the target genes of the DE miRNAs were mainly involved in zinc ion binding, regulation of cell growth, MAPK signaling pathway, and other adipose hypertrophy-related pathways. Six DE miRNAs were randomly selected and their expression profiles were validated by q-PCR. In summary, we provide the first report of the miRNA profiles of rabbit adipose tissue during different growth stages. Our data provide a theoretical reference for subsequent studies on rabbit genetics, breeding and the regulatory mechanisms of adipose development.

developmental biology↗

bioRxiv2018

Synergistic antifungal effect of amphotericin B-loaded PLGA nanoparticles based ultrasound against C. albicans biofilms

C. albicans is human opportunistic pathogens that cause superficial and life-threatening infections. An important reason for the failure of current antifungal drugs is related to biofilm formation mostly associated with implanted medical device. The present study aims to investigate the synergistic antifungal efficacy of low-frequency and low-intensity ultrasound combined with amphotericin B-loaded PLGA nanoparticles (AmB-NPs) on C.albicans biofilms. AmB-NPs were prepared by a double emulsion method and demonstrated the lower toxicity than free AmB, after which biofilms were established and treated with ultrasound and AmB-NPs separately or jointly in vitro and in vivo. The results demonstrated the activity, biomass, and proteinase and phospholipase activities of biofilms were decreased significantly after the combination treatment of AmB-NPs with 42 KHz ultrasound irradiation at an intensity of 0.30 W/cm2 for 15 min compared to the control, the AmB alone or the ultrasound alone treatment (P < 0.01), and the morphology of biofilms was altered remarkably after jointly treatment under CLSM observation and detection, especially thickness thinning and structure loosing. Furthermore, the same synergistic effects were proved in a subcutaneous catheter biofilm rat model. The result of colony forming units of catheter fungus loading exhibited a significant reduction after AmB-NPs and ultrasound jointly treatment for 7 days continuous therapy, and the CLSM images revealed that the biofilm on the catheter surface was substantially eliminated. Our study may provide a new noninvasive, safe and effective application to C.albicans biofilm infection therapy.

microbiology↗