Mechanisms by which sheep milk consumption ameliorates insulin resistance in high-fat diet-fed mice.

Sheep milk is rich in fat, protein, vitamins and minerals and is also one of the most important sources of natural bioactives. Several biopeptides in sheep milk have been reported to possess antibacterial, antiviral and anti-inflammatory properties, and they may prevent type 2 diabetes (T2D), disease and cancer. However, the precise mechanism(s) underlying the protective role of sheep milk against T2D development remains unclear. Therefore, in the current study, we investigated the effect of sheep milk on insulin resistance and glucose intolerance in high-fat diet (HFD)-fed mice, by conducting intraperitoneal glucose tolerance tests, metabolic cage studies, genomic sequencing, polymerase chain reaction, and biochemical assays. Hyperinsulinemic-euglycemic clamp-based experiments revealed that mice consuming sheep milk exhibited lower hepatic glucose production than mice in the control group. These findings further elucidate the mechanism by which dietary supplementation with sheep milk alleviates HFD-induced systemic glucose intolerance.

A strategy for Cas13 miniaturization based on the structure and AlphaFold.

The small size of the Cas nuclease fused with various effector domains enables a broad range of function. Although there are several ways of reducing the size of the Cas nuclease complex, no efficient or generalizable method has been demonstrated to achieve protein miniaturization. In this study, we establish an Interaction, Dynamics and Conservation (IDC) strategy for protein miniaturization and generate five compact variants of Cas13 with full RNA binding and cleavage activity comparable the wild-type enzymes based on a combination of IDC strategy and AlphaFold2. In addition, we construct an RNA base editor, mini-Vx, and a single AAV (adeno-associated virus) carrying a mini-RfxCas13d and crRNA expression cassette, which individually shows efficient conversion rate and RNA-knockdown activity. In summary, these findings highlight a feasible strategy for generating downsized CRISPR/Cas13 systems based on structure predicted by AlphaFold2, enabling targeted degradation of RNAs and RNA editing for basic research and therapeutic applications.

Optimizing human α-galactosidase for treatment of Fabry disease.

Fabry disease is caused by a deficiency of α-galactosidase A (GLA) leading to the lysosomal accumulation of globotriaosylceramide (Gb3) and other glycosphingolipids. Fabry patients experience significant damage to the heart, kidney, and blood vessels that can be fatal. Here we apply directed evolution to generate more stable GLA variants as potential next generation treatments for Fabry disease. GLAv05 and GLAv09 were identified after screening more than 12,000 GLA variants through 8 rounds of directed evolution. Both GLAv05 and GLAv09 exhibit increased stability at both lysosomal and blood pH, stability to serum, and elevated enzyme activity in treated Fabry fibroblasts (19-fold) and GLA-/- podocytes (10-fold). GLAv05 and GLAv09 show improved pharmacokinetics in mouse and non-human primates. In a Fabry mouse model, the optimized variants showed prolonged half-lives in serum and relevant tissues, and a decrease of accumulated Gb3 in heart and kidney. To explore the possibility of diminishing the immunogenic potential of rhGLA, amino acid residues in sequences predicted to bind MHC II were targeted in late rounds of GLAv09 directed evolution. An MHC II-associated peptide proteomics assay confirmed a reduction in displayed peptides for GLAv09. Collectively, our findings highlight the promise of using directed evolution to generate enzyme variants for more effective treatment of lysosomal storage diseases.

Lilly's Technique for Delayed Hemorrhage After Choledochal Cyst Radical Surgery.

Background: Choledochal cysts (CCs) are characterized by dilations of the extra- and/or intrahepatic bile ducts. Surgery (cyst excision and Roux-en-Y hepaticojejunostomy) remains the gold standard for treatment. However, delayed hemorrhage can occur postoperatively, and although rare, it can be life-threatening. This study aimed to determine the risk factors and corresponding prevention of delayed hemorrhage after radical CC surgery, and to apply a technique to lower its incidence. Materials and Methods: This retrospective study enrolled 267 patients who received CC surgery between June 2016 and December 2020 at Shenzhen Children's Hospital. Univariate and multivariate logistic regression analyses were performed to identify risk factors for delayed hemorrhage. Results: Eleven (4.1%) patients had delayed hemorrhage after laparoscopic radical surgery. The most common hemorrhage site was the dissected surface between the cyst and adjacent structures with chronic severe adhesions, postoperatively. The occurrence of recurrent CC-associated complication and excessive total blood loss during surgery were risk factors for delayed hemorrhage after CC radical surgery. Length of disease course, operation when cholangitis/pancreatitis still existed, cyst diameter, and application of trypsin inhibitor after the surgery were not significantly different between the two groups. Conclusion: For patients without adhesions, complete cyst resection is the gold standard. However, for those with intensive adhesions, in cases of delayed hemorrhage on the dissection surface and malignancy transformation risk, the Lilly's technique with Roux-en-Y hepaticojejunostomy could be an alternative.

Interaction between human leukocyte antigen (HLA-C) and killer cell Ig-like receptors (KIR2DL) inhibits the cytotoxicity of natural killer cells in patients with hepatoblastoma.

Background: Hepatoblastoma (HB) is the most common liver malignancy in childhood with poor prognosis and lack of effective therapeutic targets. Single-cell transcriptome sequencing technology has been widely used in the study of malignant tumors, which can understand the tumor microenvironment and tumor heterogeneity. Materials and methods: Two children with HB and a healthy child were selected as the research subjects. Peripheral blood and tumor tissue were collected for single-cell transcriptome sequencing, and the sequencing data were compared and analyzed to describe the differences in the immune microenvironment between children with HB and normal children. Results: There were significant differences in the number and gene expression levels of natural killer cells (NK cells) between children with HB and normal children. More natural killer cells were seen in children with HB compared to normal control. KIR2DL were highly expressed in children with HB. Conclusion: Single-cell transcriptome sequencing of peripheral blood mononuclear cells (PBMC) and tumor tissue from children with HB revealed that KIR2DL was significantly up-regulated in NK cells from children with HB. HLA-C molecules on the surface of tumor cells interact with inhibitory receptor KIR2DL on the surface of NK cells, inhibiting the cytotoxicity of NK cells, resulting in immune escape of tumors. Inhibitors of related immune checkpoints to block the interaction between HLA-C and KIR2DL and enhance the cytotoxicity of NK cells, which may be a new strategy for HB treatment.

A chemoenzymatic strategy for site-selective functionalization of native peptides and proteins.

The emergence of new therapeutic modalities requires complementary tools for their efficient syntheses. Availability of methodologies for site-selective modification of biomolecules remains a long-standing challenge, given the inherent complexity and the presence of repeating residues that bear functional groups with similar reactivity profiles. We describe a bioconjugation strategy for modification of native peptides relying on high site selectivity conveyed by enzymes. We engineered penicillin G acylases to distinguish among free amino moieties of insulin (two at amino termini and an internal lysine) and manipulate cleavable phenylacetamide groups in a programmable manner to form protected insulin derivatives. This enables selective and specific chemical ligation to synthesize homogeneous bioconjugates, improving yield and purity compared to the existing methods, and generally opens avenues in the functionalization of native proteins to access biological probes or drugs.

LncRNA NFIA-AS2 promotes glioma progression through modulating the miR-655-3p/ZFX axis.

Long non-coding RNAs (lncRNAs) are closely associated with tumorigenesis of various malignancies, including glioma. However, the roles of most lncRNAs in glioma remain undiscovered. The present study for the first time explored the roles of NFIA-AS2 in glioma. Based on informatic analyses by online database, lncRNA NFIA-AS2 in glioma tissues was overexpressed and further confirmed in glioma tissues and cells by quantitative real-time PCR (qRT-PCR). High expression of NFIA-AS2 was closely correlated with poor prognosis and might be an independent prognostic factor for PFS and OS. Functionally, silenced NFIA-AS2 could remarkably hinder glioma cell proliferation, migration and invasion, and cause the apoptosis. Mechanistic investigation disclosed that NFIA-AS2 interacted with miR-655-3p and inversely connected with miR-655-3p in glioma. Additionally, miR-655-3p was proved to regulate the expression of ZFX. Final rescue assay demonstrated that ZFX overexpression or miR-655-3p downregulation could neutralize the suppressive effects of NFIA-AS2 knockdown on glioma progression. In conclusion, this study firstly reported that NFIA-AS2 could promote the progression of glioma by targeting the miR-665-3p/ZFX axis, which highlighted that NFIA-AS2 could be a novel biomarker and therapeutic target for glioma patients.

Nanodiamond-Mediated Delivery of a G9a Inhibitor for Hepatocellular Carcinoma Therapy.

Hepatocellular carcinoma (HCC) is the most common primary liver cancer with high mortality but limited therapeutic options. Epigenetic regulations including DNA methylation and histone modification control gene expressions and play a crucial role during tumorigenesis. G9a, also known as EHMT2 (euchromatic histone-lysine N-methyltransferase 2), is a histone methyltransferase predominantly responsible for dimethylation of histone H3 lysine 9 (H3K9). G9a has been shown to play a key role in promoting tumor progression. Recent studies have identified that G9a is a critical mediator of HCC pathogenesis. UNC0646 is a G9a inhibitor that has shown potent in vitro efficacy. However, due to its water insolubility, the in vivo efficacy of UNC0646 is not satisfactory. In this study, nanodiamonds (NDs) were utilized as a drug delivery platform to improve in vivo delivery of this small-molecule inhibitor. Our results showed that ND-UNC0646 complexes could be rapidly synthesized by physical adsorption, meanwhile possessing favorable drug delivery properties and was able to improve the dispersibility of UNC0646 in water, therefore making it amenable for intravenous administration. The release profile of UNC0646 from ND-UNC0646 was demonstrated to be pH-responsive. Moreover, ND-UNC0646 maintained the biological functionality of UNC0646, with higher efficacy in reducing H3K9 methylation as well as enhanced invasion suppressive effects. Most importantly, increased in vivo efficacy was demonstrated using an orthotopic HCC mouse model, which paves the way of translating this small-molecule inhibitor toward HCC treatment. Our work demonstrates the potential of NDs in the clinical application for HCC treatment.

[Association of metabolic syndrome and colorectal cancer].

OBJECTIVE: To evaluate the association between metabolic syndrome and colorectal cancer. METHODS: A multicenter case-control study was conducted. A total of 1506 cases of colorectal cancer (936 males and 570 females), whose clinical data were complete and aged from 30 to 75, were collected in the Third, First and Second People's Hospital of Jingdezhen between 2000 and 2009. A total of 3354 controls (1766 males and 1588 females) were subjects admitted to the above 3 hospitals as cases with acute non-malignant non-digestive diseases. Multiple logistic regression models were used to analyze the association between metabolic syndrome and its components and colorectal cancer. RESULTS: Forty-eight cases of colorectal cancer (3.2%) and 59 controls (1.8%) were diagnosed as metabolic syndrome. Colorectal cancer risk was increased in cases with metabolic syndrome (OR=1.64, 95% CI:1.14-2.49, P<0.05) and in men with metabolic syndrome (OR=1.92, 95% CI:1.27-3.78, P<0.05), but not in women (P>0.05). As the number of component of metabolic syndrome increased, the risk of colorectal cancer increased in men (P<0.01), but not in women (P>0.05). CONCLUSION: Association between metabolic syndrome and colorectal cancer exists in men, but not in women.

Fragment-based design of small molecule X-linked inhibitor of apoptosis protein inhibitors.

We report on a general structure- and NMR-based approach to derive druglike small molecule inhibitors of protein-protein interactions in a rapid and efficient manner. We demonstrate the utility of the approach by deriving novel and effective SMAC mimetics targeting the antiapoptotic protein X-linked inhibitor of apoptosis protein (XIAP). The XIAP baculovirus IAP repeat 3 (Bir3) domain binds directly to the N-terminal of caspase-9, thus inhibiting programmed cell death. It has been shown that in the cell this interaction can be displaced by the protein second mitochondrial activator of caspases (SMAC) and that its N-terminal tetrapeptide region (NH2-AVPI, Ala-Val-Pro-Ile) is responsible for this activity. However, because of their limited cell permeability, synthetic SMAC peptides are inefficient when tested in cultured cells, limiting their use as potential chemical tools or drug candidates against cancer cells. Hence, as an application, we report on the derivation of novel, selective, druglike, cell permeable SMAC mimics with cellular activity.

Lack of effect of P-glycoprotein inhibition on renal clearance of dicloxacillin in patients with cystic fibrosis.

STUDY OBJECTIVE: To determine whether upregulation of P-glycoprotein is responsible for the enhanced renal clearance of dicloxacillin in patients with cystic fibrosis. DESIGN: Single-center, prospective, open-label, randomized, three-part crossover pharmacokinetic study. SETTING: General clinical research center. SUBJECTS: Eleven patients with cystic fibrosis and 11 age-matched healthy volunteers. INTERVENTION: All subjects received a single oral dose of dicloxacillin 500 mg alone, dicloxacillin 500 mg plus probenecid (an organic anion transport inhibitor) 1 g, and dicloxacillin 500 mg plus cyclosporine (a P-glycoprotein inhibitor) 5 mg/kg; each treatment was separated by a washout period of 48 hours. A bolus dose of iothalamate meglumine 456 mg was administered on each study day as a marker of glomerular filtration. MEASUREMENTS AND MAIN RESULTS: Blood and urine samples were taken serially up to 6 hours after each dose. Pharmacokinetics of dicloxacillin and iothalamate were determined by using compartmental and noncompartmental methods. Quantitative polymerase chain reaction was performed on peripheral blood mononuclear cells to measure expression of multidrug resistance 1 (MDR1) messenger RNA (mRNA). Genotyping for ABCB1 was performed to determine the presence of single nucleotide polymorphisms (exons 21 and 26). In both healthy subjects and patients with cystic fibrosis, compared with dicloxacillin alone, coadministration with probenecid produced a significantly lower renal clearance of dicloxacillin, whereas coadministration with cyclosporine resulted in no significant change; renal clearance was not significantly different between the two study groups. No correlation was found between MDR1 mRNA expression and renal clearance of dicloxacillin. The renal excretion of dicloxacillin was significantly greater in subjects with the ABCB1 exon 26 TT polymorphism when compared with subjects with the CT genotype. CONCLUSION: We found no significant difference in the pharmacokinetics of dicloxacillin between patients with cystic fibrosis and healthy volunteers. Renal clearance of dicloxacillin was significantly reduced in the presence of probenecid but not with cyclosporine, suggesting that the rate-limiting step in tubular secretion of dicloxacillin is uptake mediated by the organic anion transporter, and not P-glycoprotein inhibition.

Quantum mechanical design of enzyme active sites.

The design of active sites has been carried out using quantum mechanical calculations to predict the rate-determining transition state of a desired reaction in presence of the optimal arrangement of catalytic functional groups (theozyme). Eleven versatile reaction targets were chosen, including hydrolysis, dehydration, isomerization, aldol, and Diels-Alder reactions. For each of the targets, the predicted mechanism and the rate-determining transition state (TS) of the uncatalyzed reaction in water is presented. For the rate-determining TS, a catalytic site was designed using naturalistic catalytic units followed by an estimation of the rate acceleration provided by a reoptimization of the catalytic site. Finally, the geometries of the sites were compared to the X-ray structures of related natural enzymes. Recent advances in computational algorithms and power, coupled with successes in computational protein design, have provided a powerful context for undertaking such an endeavor. We propose that theozymes are excellent candidates to serve as the active site models for design processes.

A fragment-based approach for the discovery of isoform-specific p38alpha inhibitors.

In this study, we describe a novel approach for lead discovery against protein kinases, pharmacophore by interligand nuclear Overhauser effect (ILOE), in which a pair of ligands that bind to adjacent pockets on the target surface is identified by the detection of protein-mediated ILOEs. We demonstrate that a pharmacophore-based search guided by experimental binding data of weakly interacting fragments can be rapidly and efficiently used to identify (or synthesize) high-affinity, selective ligands. Targeting the inactive state of protein kinases represents a promising approach to achieve selectivity and cellular efficacy. In this respect, when we apply the method for the discovery of potent p38alpha inhibitors, we also demonstrate that the resulting bidentate compounds are highly selective and exhibit a cellular activity that parallels their in vitro binding to the inactive form of the kinase. The method is relatively simple and of general applicability, and as such we anticipate its potential implementation against a variety of macromolecular targets, including not only protein kinases but also those involved in protein-protein interactions or even nucleic acids.

Mechanism of the glutathione transferase-catalyzed conversion of antitumor 2-crotonyloxymethyl-2-cycloalkenones to GSH adducts.

Human glutathione (GSH) transferase (hGSTP1-1) processes with similar kinetic efficiencies the antitumor agents 2-crotonyloxymethyl-2-cyclohexenone (COMC-6), 2-crotonyloxymethyl-2-cycloheptenone (COMC-7), and 2-crotonyloxymethyl-2-cyclopentenone (COMC-5) to 2-glutathionylmethyl-2-cyclohexenone, 2-glutathionylmethyl-3-glutathionyl-2-cycloheptenone, and 2-glutathionylmethyl-2-cyclopentenone, respectively. This process likely involves initial enzyme-catalyzed Michael addition of GSH to the COMC derivative to give a glutathionylated enol(ate), which undergoes nonstereospecific ketonization, either while bound to the active site or free in solution, to a glutathionylated exocyclic enone. Free in solution, GSH reacts at the exomethylene carbon of the exocyclic enone, displacing the first GSH to give the final product. This mechanism is supported by the observation of multiphasic kinetics in the presence of high concentrations of hGSTP1-1 and the ability to trap kinetically competent exocyclic enones in aqueous acid using COMC-6 and COMC-7 as substrates. That the exocyclic enone is formed by nonstereospecific ketonization of an enol(ate) species is indicated by the observation that COMC-6 (chirally labeled with deuterium at the exomethylene carbon) gives stereorandomly labeled exocyclic enone. The isozymes hGSTP1-1, hGSTA1-1, hGSTA4-4, and hGSTM2-2 catalyze the conversion of COMC-6 to final product with similar efficiencies (K(m) = 0.08-0.34 mM, k(cat) = 1.5-6.1 s(-)(1)); no activity was detected with the rat rGSTT2-2 isozyme. Molecular docking studies indicate that in hGSTP1-1, the hydroxyl group of Tyr108 might serve as a general acid catalyst during substrate turnover. The possible significance of these observations with respect to the metabolism of COMC derivatives in multidrug resistant tumors is discussed.