Novel nucleic acid detection strategies based on CRISPR-Cas systems: From construction to application

Beyond their widespread application as genome-editing and regulatory tools, clustered regularly interspaced short palindromic repeats (CRISPR)-CRISPR-associated (Cas) systems also play a critical role in nucleic acid detection due to their high sensitivity and specificity. Recently developed Cas family effectors have opened the door to the development of new strategies for detecting different types of nucleic acids for a variety of purposes. Precise and efficient nucleic acid detection using CRISPR-Cas systems has the potential to advance both basic and applied biological research. In this review, we summarize the CRISPR-Cas systems used for the recognition and detection of specific nucleic acids for different purposes, including the detection of genomic DNA, nongenomic DNA, RNA, and pathogenic microbe genomes. Current challenges and further applications of CRISPR-based detection methods will be discussed according to the most recent developments.     

Combined effects of avasimibe immunotherapy,doxorubicin chemotherapy,and metal–organic frameworks nanoparticles on breast cancer

CD8⁺ T cells play a vital role in cancer immunotherapy and can be shaped by metabolism. Avasimibe is an acyl coenzyme A-cholesterol acyltransferase (ACAT) inhibitor, which has been clinically verified safe in other phase Ⅲ clinical trials. It can potentiate the killing function of CD8⁺ T cells by modulating cholesterol metabolism. Doxorubicin (DOX) is an anticancer drug widely used in many cancers to induce tumor cell apoptosis. Unfortunately, DOX also can induce toxic and side effects in many organs, compromising its usage and efficacy. Herein, we report the combinational usage of avasimibe and a safe pH sensitive nano-drug delivery system composing of DOX and metal–organic frameworks nanoparticles (MNPs). Our findings demonstrated that DOX–MNPs treatment inhibited tumor growth with good safety profile and avasimibe treatment combined DOX–MNPs treatment exhibited a better efficacy than monotherapies in 4T1 breast cancer therapy.     

Umbilical cord-derived mesenchymal stromal/stem cells expressing IL-24 induce apoptosis in gliomas

Although much progress has been made in the treatment of gliomas, the prognosis for patients with gliomas is still very poor. Stem cell-based therapies may be promising options for glioma treatment. Recently, many studies have reported that umbilical cord-derived mesenchymal stromal/stem cells (UC-MSCs) are ideal gene vehicles for tumor gene therapy. Interleukin 24 (IL-24) is a pleiotropic immunoregulatory cytokine that has an apoptotic effect on many kinds of tumor cells and can inhibit the growth of tumors specifically without damaging normal cells. In this study, we investigated UC-MSCs as a vehicle for the targeted delivery of IL-24 to tumor sites. UC-MSCs were transduced with lentiviral vectors carrying green fluorescent protein (GFP) or IL-24 complementary DNA. The results indicated that UC-MSCs could selectively migrate to glioma cells in vitro and in vivo. Injection of IL-24-UC-MSCs significantly suppressed tumor growth of glioma xenografts. The restrictive efficacy of IL-24-UC-MSCs was associated with the inhibition of proliferation as well as the induction of apoptosis in tumor cells. These findings indicate that UC-MSC-based IL-24 gene therapy may be able to suppress the growth of glioma xenografts, thereby suggesting possible future therapeutic use in the treatment of gliomas.     

Retracted: Rs11655237 polymorphism of LINC00673 affects the prognosis of cervical cancer by interfering with the interaction between LINC00673 and microRNA-1231

Single-nucleotide polymorphism (SNP) in long noncoding RNAs (lncRNAs) is known to disrupt the binding between lncRNAs and microRNAs. In this paper, we aimed to explore the role of LINC00673 rs11655237 SNP in the survival of cervical cancer (CC). Real-time polymerase chain reaction and western-blot analysis were used to detect expressions of LINC00673 and microRNA-1231 (miR-1231) in CC patients with different rs11655237 SNP genotypes. And the expression of LINC00673, miR-1231, and IFNAR1 was measured in mice and cells treated with exosomes carrying GG, GA, and AA rs11655237 genotypes. Compared with patients carrying the rs11655237 A allele of LINC00673 rs11655237 SNP, patients carrying the G allele showed higher overall survival and higher miR-1231 expression. In addition, the expression of miR-1231 was the highest in patients carrying the GG genotype and the lowest in patients carrying the AA genotype. Furthermore, the exosomes carrying GG, GA, and AA genotypes of LINC00673 rs11655237 SNP reduced tumor growth in mice, while the inhibitory effect of rs11655237 A allele was much stronger than that of the rs11655237 G allele. Additionally, exosome treatment upregulated the expression of LINC000673 and IFNAR1 while downregulating the expression of miR-1231. Interestingly, the A allele of rs11655237 generated a binding site for miR-1231 and subsequently affected the expression of IFNAR1, a target gene of miR-1231 containing a miR-1231 binding site in its 3′-untranslated region. Cells transfected with exosomes carrying GG, GA, and AA genotypes of LINC00673 rs11655237 SNP achieved higher LINC000673 and IFNAR1 expression along with lower miR-1231 expression. Therefore, rs11655237 can be used as a prognostic biomarker for CC.     

Toll-like receptor 4 contributes to uterine activation by upregulating pro-inflammatory cytokine and CAP expression via the NF-κB/P38MAPK signaling pathway during pregnancy

Evidence indicates that inflammatory response is significant during the physiological process of human parturition; however, the specific signaling pathway that triggers inflammation is undefined. Toll-like receptors (TLRs) are key upstream gatekeepers that control inflammatory activation before preterm delivery. Our previous study showed that TLR4 expression was significantly increased in human pregnancy tissue during preterm and term labor. Therefore, we explore whether TLR4 plays a role in term labor by initiating inflammatory responses, therefore promoting uterine activation. The results showed that expression of TLR4, interleukin-1β (IL-1β), IL-6, tumor necrosis factor-α (TNF-α), CC chemokine ligand 2 (CCL-2), and uterine contraction-associated proteins (CAPs) was upregulated in the human and mice term labor (TL) group compared with the not-in-labor (TNL) group, and the TLR4 level positively correlated with CAP expression. In pregnant TLR4-knockout (TLR4^−/−) mice, gestation length was extended by 8 hr compared with the wild-type group, and the expression of IL-1β, IL-6, TNF-α, CCL-2, and CAPs was decreased in TLR4^−/− mice. Furthermore, nuclear factor-κB (NF-κB) and P38MAPK activation is involved in the initiation of labor but was inhibited in TLR4^−/− mice. In uterine smooth muscle cells, the expression of inflammatory cytokines and CAPs decreased when the NF-κB and P38MAPK pathway was inhibited. Our data suggest that TLR4 is a key factor in regulating the inflammatory response that drives uterine activation and delivery initiation via activating the NF-κB/P38MAPK pathway.     

Protective effects of irisin on hypoxia-reoxygenation injury in hyperglycemia-treated cardiomyocytes: Role of AMPK pathway and mitochondrial protection

Recent evidence has verified the cardioprotective actions of irisin in different diseases models. However, the beneficial action of irisin on hypoxia-reoxygenation (HR) injury under high glucose stress has not been described. Herein our research investigated the influence of irisin on HR-triggered cardiomyocyte death under high glucose stress. HR model was established in vitro under high glucose treatment. The results illuminated that HR injury augmented apoptotic ratio of cardiomyocyte under high glucose stress; this effect could be abolished by irisin via modulating mitochondrial function. Irisin treatment attenuated cellular redox stress, improved cellular ATP biogenetics, sustained mitochondria potential, and impaired mitochondrion-related cell death. At the molecular levels, irisin treatment activated the 5′-adenosine monophosphate-activated protein kinase (AMPK) pathway and the latter protected cardiomyocyte and mitochondria against HR injury under high glucose stress. Altogether, our results indicated a novel role of irisin in HR-treated cardiomyocyte under high glucose stress. Irisin-activated AMPK pathway and the latter sustained cardiomyocyte viability and mitochondrial function.     

Identification of methylation-driven genes related to prognosis in clear-cell renal cell carcinoma

With the participation of the existing treatment methods, the prognosis of advanced clear-cell renal cell carcinoma (ccRCC) is poor. More evidence indicates the presence of methylation in ccRCC cancer cells, but there is a lack of studies on methylation-driven genes in ccRCC. We analyzed the open data of ccRCC in The Cancer Genome Atlas database to obtain ccRCC-related methylation-driven genes, and then carried out pathway enrichment, survival, and joint survival analyses. More important, we deeply explored the correlation between differential methylation sites and the expression of these driving genes. Finally, we screened 29 methylation-driven genes via MethylMix, of which six were significantly associated with the survival of ccRCC patients. This study demonstrated that the effect of hypermethylation or hypomethylation on prognosis is different, and the level of methylation of key methylation sites is associated with gene expression. We identified methylation-driven genes independently predicting prognosis in ccRCC, which offers theoretical support in bioinformatics for the study of methylation in ccRCC and a new perspective for the epigenetic study of ccRCC.     

小白链霉菌ε-聚赖氨酸降解酶生理功能分析

[目的] 研究小白链霉菌（Streptomyces albulus）中ε-聚赖氨酸降解酶（Pld）的分布特征和生理功能。[方法] 利用生物信息学手段对已报道的ε-聚赖氨酸（ε-PL）产生菌的Pld进行挖掘和分析,再通过遗传学方法对小白链霉菌M-Z18基因组中存在的两种pld进行敲除、回补和过表达,最后研究重组菌降解ε-PL能力、最小ε-PL抑制浓度（MIC）及其合成ε-PL情况。[结果] PldⅠ和PldⅡ广泛且同时分布于小白链霉菌中,蛋白序列高度保守;PldⅠ、PldⅡ在小白链霉菌M-Z18中均能行使降解ε-PL的功能,但PldⅡ降解活性占主导地位且PldⅠ和PldⅡ对降解ε-PL具有协同作用;pldⅠ、pldⅡ过表达重组菌对ε-PL的MIC值显著提高,其中双过表达pldⅠ和pldⅡ菌株对ε-PL的MIC值是出发菌株的2.19倍。构建的pld重组菌与出发菌株相比,在考察pH值范围内（pH 3.0-5.5）的ε-PL产量未表现出显著差异。[结论] 小白链霉菌中广泛分布PldⅠ和PldⅡ且序列高度保守,主要生理功能是保护小白链霉菌在中性环境中免受自身产物ε-PL的抑制。