One-step modification to identify dual-inhibitors targeting both pancreatic triglyceride lipase and Niemann-Pick C1-like 1

Pancreatic triglyceride lipase (PTL) and Niemann-Pick C1-like 1 (NPC1L1) have been identified as attractive therapeutic targets for obesity and hypercholesteremia, respectively. Obesity and hypercholesteremia usually co-exist, however no dual-inhibitors against PTL and NPC1L1 were reported for the treatment of obesity patients with hypercholesteremia so far. In this work, molecular hybridization-based one-step modification screening identified a potent dual-inhibitor against PTL and NPC1L1. Compound P1-11 has IC₅₀ values of 2.1 μM against PTL through covalent binding, as well as significantly reduces cholesterol absorption in a non-competitive inhibitory manner. Molecule docking and molecular dynamics studies revealed the reason of its activity to both PTL and NPC1L1. Moreover, the gene and protein expression levels of PTL and NPC1L1 were also determined respectively after the treatment of P1-11. Development of dual-inhibitors against PTL and NPC1L1 could provide novel treatment options for obesity patients with hypercholesteremia. The results of current research would great support the development of dual-inhibitors against PTL and NPC1L1.

Recent advances in the regulation of ABCA1 and ABCG1 by lncRNAs

Coronary heart disease (CHD) with atherosclerosis is the leading cause of death worldwide. ABCA1 and ABCG1 promote cholesterol efflux to suppress foam cell generation and reduce atherosclerosis development. Long noncoding RNAs (lncRNAs) are emerging as a unique group of RNA transcripts that longer than 200 nucleotides and have no protein-coding potential. Many studies have found that lncRNAs regulate cholesterol efflux to influence atherosclerosis development. ABCA1 is regulated by different lncRNAs, including MeXis, GAS5, TUG1, MEG3, MALAT1, Lnc-HC, RP5-833A20.1, LOXL1-AS1, CHROME, DAPK1-IT1, SIRT1 AS lncRNA, DYNLRB2-2, DANCR, LeXis, LOC286367, and LncOR13C9. ABCG1 is also regulated by different lncRNAs, including TUG1, GAS5, RP5-833A20.1, DYNLRB2-2, ENST00000602558.1, and AC096664.3. Thus, various lncRNAs are associated with the roles of ABCA1 and ABCG1 on cholesterol efflux in atherosclerosis regulation. However, some lncRNAs play dual roles in ABCA1 expression and atherosclerosis, and the functions of some lncRNAs in atherosclerosis have not been investigated in vivo. In this article, we review the roles of lncRNAs in atherosclerosis and focus on new insights into lncRNAs associated with the roles of ABCA1 and ABCG1 on cholesterol efflux and the potential of these lncRNAs as novel therapeutic targets in atherosclerosis.

Circulating microRNAs: Biomarkers of disease

MicroRNAs are a class of endogenous noncoding single-stranded RNA molecules with approximately 20-24 nucleotides and are associated with a broad range of biological processes. Researchers found that microRNAs are abundant in tissues, and more importantly, there are also trace circulating microRNAs that exist in biological fluids. In recent years, circulating microRNAs had emerged as promising diagnostic and prognostic biomarkers for the noninvasive detection of diseases with high specificity and sensitivity. More importantly, specific microRNA expression signatures reflect not only the existence of early-stage diseases but also the dynamic development of advanced-stage diseases, disease prognosis prediction, and drug resistance. To date, an increasing number of potential miRNA biomarkers have been reported, but their practical application prospects are still unclear. Therefore, microRNAs, as potential diagnostic and prognostic biomarkers in a variety of diseases, need to be updated, as they are of great importance in the diagnosis, prognosis and prediction of therapeutic responses. In this review, we summary our current understanding of microRNAs as potential biomarkers in the major diseases (e.g., cancers and cardio-cerebrovascular diseases), which provide the basis for the design of diagnosis and treatment plan and the improvement of the cure rate.

A facile ligand-free route to calcium carbonate superstructures

By capturing the inherent transition behavior, CaCO3 superstructures with well-defined morphologies and amorphous-to-vaterite polymorph nature were obtained in a large scale and ligand-free manner.

Association of phosphoenolpyruvate carboxykinase 1 protein kinase activity-dependent sterol regulatory element-binding protein 1 activation with prognosis of oesophageal carcinoma

BACKGROUND

Metabolic enzymes have non-canonical functions and play vital roles in the regulation of various cellular activities. Phosphoenolpyruvate carboxykinase 1 (PCK1), a gluconeogenic enzyme, was recently identified as an AKT-dependent protein kinase and promoted sterol regulatory element-binding protein 1 (SREBP1)-dependent lipogenesis. However, association of this protein kinase activity of PCK1 with progression of oesophageal squamous cell carcinoma (ESCC) is unclear.

METHODS

We examined 200 ESCC patient samples and prognosis using immunohistochemistry, multivariate Cox regression and Kaplan-Meier Plot analyses.

RESULTS

We show that the expression levels of AKT pS473, AKT-regulated PCK1 pS90, PCK1-mediated INSIG1 pS207/INSIG2 pS151 and nuclear SREBP1 were higher in analysed 200 human ESCC specimens than in their adjacent non-tumour tissues; the expression levels of these proteins were significantly and positively correlated with each other in tumour specimens. In addition, the expression levels of PCK1 pS90, INSIG1 pS207/INSIG2 pS151 and SREBP1 were associated with the tumour, node and metastasis stage and progression in ESCC. Importantly, levels of PCK1 pS90 or INSIG1 pS207/INSIG2 pS151 or nuclear SREBP1 were positively correlated with poor prognosis in patients with ESCC, and the combined expression values of PCK1 pS90, INSIG1 pS207/INSIG2 pS151 and nuclear SREBP1 had a better prognostic value than that of each individual protein expression value and was an independent prognostic marker for ESCC.

CONCLUSION

These findings reveal the role of PCK1 protein kinase activity-dependent SREBP1 activation in ESCC progression. The regulation of SREBP1 by AKT activation-dependent PCK1 protein kinase activity may provide the potential for the diagnosis and treatment of human ESCC.

Ultrasonic evaluation of systemic and renal perfusion in sepsis patients before and after fluid resuscitation

OBJECTIVE

This study aimed to explore the significance of renal Doppler ultrasound in evaluating systemic and renal perfusion in sepsis patients before and after fluid resuscitation.

PATIENTS AND METHODS

Forty sepsis patients admitted to the Department of Intensive Medicine and intensive care unit (ICU) of the Fourth Hospital of Hebei Medical University from June 2014 to December 2014 were enrolled in this study, and 35 patients were included in the final analysis. These patients were divided into positive and negative fluid responsiveness groups. They were also divided into an acute kidney injury (AKI) group and a non-AKI group according to changes in creatinine and urine volume. The correlations of the changes in hemodynamics before and after fluid resuscitation in each group with the changes in renal resistance index (RRI) and renal blood flow (RBF) grades were evaluated.

RESULTS

Before and after fluid resuscitation, the heart rate (HR), blood creatinine (Cre), and lactate (Lac) levels of all patients, including the patients in the positive fluid responsiveness group decreased, and the stroke volume (SV) and central venous pressure (CVP) increased. Only HR decreased in the negative fluid responsiveness group. In the AKI group, HR, Cre, and Lac decreased, while in the non-AKI group, HR decreased, but CVP and SV increased. There were differences between HR, Lac, and change rate of Lac (Lac%) after fluid resuscitation for the positive and negative fluid responsiveness groups. There was no statistical difference between the RRI values of each group before and after fluid resuscitation. The RRI values of the AKI group were higher than those of the non-AKI group, while the AKI group's RBF grades were lower than those of the non-AKI group. The change rate of RRI (RRI%) was higher in the AKI group than in the non-AKI group. Except for the negative fluid responsiveness group, the RBF grade of each group increased.

CONCLUSIONS

The approach of RBF classification based on Doppler ultrasound can be used to evaluate the systemic and renal perfusion of patients with severe sepsis before and after fluid resuscitation, while the RRI value cannot be used for evaluation. However, the RRI value can be used as a dynamic index for the evaluation of renal perfusion in patients with AKI.

lncRNA ROR Promotes Gastric Cancer Drug Resistance

OBJECTIVE

Gastric cancer is one of the most common malignant tumors worldwide, and for resectable tumors, the most effective treatment is surgery with chemotherapy in neoadjuvant or adjuvant setting. However, the majority of patients fail to achieve the ideal initial response and/or develop resistance to chemotherapy. It was reported that long noncoding RNA regulator of reprogramming (ROR) is highly associated with the progression of gastric cancer. However, the role ROR in multidrug resistance (MDR) remains unclear.

METHODS

The messenger RNA levels of 63 specimens of patients with gastric cancer were determined by real-time polymerase chain reaction analysis and were correlated with drug resistance and survival of patients. To determine the cellular functions of ROR, we generated gastric cancer MDR cells. The effect of ROR depletion on multidrug resistance-associated protein 1 (MRP1) expression and cell apoptosis were examined by immunoblotting analyses, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, and flow cytometry.

RESULTS

We found that ROR expression levels are positively associated with increased MDR and poor prognosis of patients with gastric cancer. Regulator of reprogramming expression is increased in gastric cancer cells resistant to adriamycin (ADR) and vincristine (VCR). Depletion of ROR reduced MRP1 expression and increased apoptosis of drug-resistant gastric cancer cells in response to ADR and VCR treatment.

CONCLUSIONS

We demonstrated that ROR expression promotes MRP1 expression and MDR of gastric cancer cells and is correlated with increased MDR and poor prognosis of patients with gastric cancer. Our finding highlighted the potential of targeting ROR to improve the efficacy of chemotherapy.

The crosstalk of ABCA1 and ANXA1: a potential mechanism for protection against atherosclerosis

Atherosclerosis, characterized by the formation of fat-laden plaques, is a chronic inflammatory disease. ABCA1 promotes cholesterol efflux, reduces cellular cholesterol accumulation, and regulates anti-inflammatory activities in an apoA-I- or ANXA1-dependent manner. The latter activity occurs by mediating the efflux of ANXA1, which plays a critical role in anti-inflammatory effects, cholesterol transport, exosome and microparticle secretion, and apoptotic cell clearance. ApoA-I increases ANXA1 expression via the ERK, p38MAPK, AKT, and PKC pathways. ApoA-I regulates the signaling pathways by binding to ABCA1, suggesting that apoA-I increases ANXA1 expression by binding to ABCA1. Furthermore, ANXA1 may increase ABCA1 expression. ANXA1 increases PPARγ expression by modulating STAT6 phosphorylation. PPARγ also increases ANXA1 expression by binding to the promoter of ANXA1. Therefore, ABCA1, PPARγ, and ANXA1 may form a feedback loop and regulate each other. Interestingly, the ANXA1 needs to be externalized to the cell membrane or secreted into the extracellular fluids to exert its anti-inflammatory properties. ABCA1 transports ANXA1 from the cytoplasm to the cell membrane by regulating lipidization and serine phosphorylation, thereby mediating ANXA1 efflux, likely by promoting microparticle and exosome release. The direct role of ABCA1 expression and ANXA1 release in atherosclerosis has been unclear. In this review, we focus on the role of ANXA1 in atheroprogression and its novel interaction with ABCA1, which may be useful for providing basic knowledge for the development of novel therapeutic targets for atherosclerosis and cardiovascular disease.

The Physiologic Activity and Mechanism of Quercetin-Like Natural Plant Flavonoids

The term "vitamin P" is an old but interesting concept. Most substances in this category belong to the family of flavonoids. "Vitamin P" has also been used to define the activity of some flavonoids, including quercetin, myricetin, and rutin. According to experimental studies, the "quercetin-like natural plant flavonoids" are beneficial to the body due to their various physiological and pharmacological activities in large doses (5 μM in vitro, 50 mg/kg in mice and 100 mg/kg in rats). The physiologically achievable concentration is 10 to 100 nM, which is quite high and hard to achieve from a normal diet. Thus, the physiologic activity and mechanism of "vitamin P" are still not clear. It should be noted that the quercetin-like natural plant flavonoids are physiological co-factors of cyclooxygenases (COXs), which are the rate-limiting key enzymes of prostaglandins. These quercetin-like natural plant flavonoids can strongly stimulate prostaglandin levels at lower doses (10 nM in vitro and in 0.1 mg/kg in vivo in rats). Although these "vitamin P" substances are not original substances in the body, their physiological functions affect the body. This review is focused on the most compelling evidence regarding the physiologic role and mechanism of quercetin-like natural plant flavonoids, which may be useful in understanding the physiological functions of "vitamin P", with the goal of focusing on the role of flavonoids in human physiological health.

Butyrate-producing bacteria and the gut-heart axis in atherosclerosis

The gut microbiota plays an important role in controlling atherosclerosis progression to support the link between the gut and coronary heart disease. Recent studies have shown that an imbalance in the gut-heart axis due to the gut microbiota plays an important role in atherosclerosis progression. The gut microbiota promotes the development of atherosclerosis by producing intermediate metabolites, including TMAO, LPS, PAGln and reducing butyrate. TMAO and PAGln might be potential biomarkers of coronary heart disease. Many studies have shown that butyrate-producing bacteria prevent atherosclerosis progression by producing butyrate and maintaining the bacterial balance, the intestinal barrier function and the expression of various genes, including those encoding lipids and those related to immunity, inflammation, differentiation, apoptosis, phagocytosis and efferocytosis. This review focuses on recent advances in our understanding of the interplay between butyrate-producing bacteria and the gut-heart axis in atherosclerosis.

The gluconeogenic enzyme PCK1 phosphorylates INSIG1/2 for lipogenesis

Cancer cells increase lipogenesis for their proliferation and the activation of sterol regulatory element-binding proteins (SREBPs) has a central role in this process. SREBPs are inhibited by a complex composed of INSIG proteins, SREBP cleavage-activating protein (SCAP) and sterols in the endoplasmic reticulum. Regulation of the interaction between INSIG proteins and SCAP by sterol levels is critical for the dissociation of the SCAP-SREBP complex from the endoplasmic reticulum and the activation of SREBPs^1,2. However, whether this protein interaction is regulated by a mechanism other than the abundance of sterol-and in particular, whether oncogenic signalling has a role-is unclear. Here we show that activated AKT in human hepatocellular carcinoma (HCC) cells phosphorylates cytosolic phosphoenolpyruvate carboxykinase 1 (PCK1), the rate-limiting enzyme in gluconeogenesis, at Ser90. Phosphorylated PCK1 translocates to the endoplasmic reticulum, where it uses GTP as a phosphate donor to phosphorylate INSIG1 at Ser207 and INSIG2 at Ser151. This phosphorylation reduces the binding of sterols to INSIG1 and INSIG2 and disrupts the interaction between INSIG proteins and SCAP, leading to the translocation of the SCAP-SREBP complex to the Golgi apparatus, the activation of SREBP proteins (SREBP1 or SREBP2) and the transcription of downstream lipogenesis-related genes, proliferation of tumour cells, and tumorigenesis in mice. In addition, phosphorylation of PCK1 at Ser90, INSIG1 at Ser207 and INSIG2 at Ser151 is not only positively correlated with the nuclear accumulation of SREBP1 in samples from patients with HCC, but also associated with poor HCC prognosis. Our findings highlight the importance of the protein kinase activity of PCK1 in the activation of SREBPs, lipogenesis and the development of HCC.

[Experimental study on the effect of olfactory training on olfactory function in mice with olfactory dysfunction]

Objective: To observe the effect of olfactory training on mice with olfactory dysfunction induced by 3-methylindole (3-MI). Methods: Thirty-one male BALB/c mice were randomly divided into 3 groups by random digits table: control group (group A, n=10), olfactory dysfunction group (group B, n=10) and olfactory dysfunction+olfactory training group (group C, n=11). Mice in group B and group C were intraperitoneally injected with 150 mg/kg 3-MI to induce olfactory dysfunction model, while mice in group A were intraperitoneally injected with corn oil of the same volume. From the first day after injection, mice in group C were treated with 4 kinds of odors by inhalation, while mice in group B were treated with distilled water by inhalation, with 2 times/d, 30 min/time/kind of odor, and continuous training for 28 d. Group A was not treated. Buried food pellet tests were conducted before injection and at 7, 14, 21 and 28 days after injection, respectively. The olfactory epithelium was harvested for observation of the number of olfactory marker protein (OMP) and the thickness of olfactory epithelium on the 28th day after injection. SPSS 23.0 software was used for statistical analysis. Results: Before injection, all mice in each group had no olfactory dysfunction. At the 7th, 14th, 21st and 28th days after injection, the food finding time of mice in group C was shorter than that in group B, and the difference was statistically significant ((175.88±100.50) s vs (266.73±46.83) s, (132.00±84.62) s vs (264.10±48.50) s, (103.57±77.43) s vs (197.43±69.78) s, (67.79±32.54) s vs (176.63±61.06) s, all P<0.05), but food finding time of mice in group B and C was longer than that in group A (the food finding time of group A at the 7th, 14th, 21st and 28th days after injection was (27.13±5.36) s, (25.83±7.28) s, (23.13±2.72) s, (26.63±7.60) s, respectively, all P<0.05). At the 28th day after olfactory training, the number of OMP positive cells in group B and C were fewer than that in group A, and the difference was statistically significant ((108.00±28.19)/HP vs (288.22±84.06)/HP, (199.33±58.55)/HP vs (288.22±84.06)/HP, all P<0.05). The number of OMP positive cells in group C were higher than that in group B (P<0.05). The number of OMP positive cells had negative correlation with food finding time (r=-0.886, P<0.01). As for the thickness of the olfactory epithelium, the thickness of group B was thinner than that in group A and C, and the difference was statistically significant ((59.57±31.27) μm vs (114.55±40.70)μm vs (90.54±37.72) μm, all P<0.05). Conclusion: Olfactory training can accelerate the recovery of olfactory function in 3-MI-induced olfactory impaired mice.

Phosphofructokinase 1 Platelet Isoform Promotes β-Catenin Transactivation for Tumor Development

Metabolism plays a critical role in direct regulation of a variety of cellular activities via metabolic enzymes and metabolites. Here, we demonstrate that phosphofructokinase 1 platelet isoform (PFKP), which catalyzes a rate-limiting reaction in glycolysis, promotes EGFR activation-induced nuclear translocation and activation of β-catenin, thereby enhancing the expression of its downstream genes CCND1 and MYC in human glioblastoma cells. Importantly, we showed that EGFR-phosphorylated PFKP Y64 has a critical role in AKT activation and AKT-mediated β-catenin S552 phosphorylation and subsequent β-catenin transactivation and promotion of tumor cell glycolysis, migration, invasion, proliferation, and brain tumor growth. These findings highlight a novel mechanism underlying a glycolytic enzyme-mediated β-catenin transactivation and underscore the integrated and reciprocal regulation of metabolism and gene expression, which are two fundamental biological processes in tumor development.

Endogenous ApoA-I expression in macrophages: A potential target for protection against atherosclerosis

ApoA-I is a major protein component of high-density lipoprotein (HDL) that is widely known for regulating cholesterol trafficking and inflammatory and immune responses and for protecting against atherosclerosis. ApoA-I is generally considered to be synthesized in the liver (hepatocytes) and small intestine (enterocytes). However, computer analysis of ApoA-I has shown that the ApoA-I gene may be expressed in not only hepatocytes and enterocytes but also monocyte-macrophage cells, dendritic cells (DCs) and T cells. ApoA-I expression has been detected in THP-1 monocytes and macrophages, peripheral blood mononuclear cells (PBMCs) from postmenopausal women, human PBMC-derived monocytes and macrophages, mouse peritoneal macrophages, etc. Endogenous ApoA-I in macrophages has anti-inflammatory and cholesterol efflux effects. However, our understanding of the detailed roles of macrophage-synthesized ApoA-I is still at an early stage and very limited. More experiments are needed to elucidate the exact roles of endogenous ApoA-I in macrophages. Several lines of evidence indicate that recombinant exogenous human ApoA-I in mouse macrophages increases cholesterol efflux and thus reduces atherosclerosis development. Considering the antiatherogenic effect of exogenous ApoA-I overexpression in mouse macrophages, better understanding the role and mechanisms underlying macrophage-synthesized ApoA-I in atherosclerosis will enable macrophage-synthesized ApoA-I therapy to open new avenues for reducing the risk of atherosclerosis.

Programmable base editing of mutated TERT promoter inhibits brain tumour growth

Clustered regularly interspaced short palindromic repeats (CRISPR), CRISPR interference and programmable base editing have transformed the manipulation of eukaryotic genomes for potential therapeutic applications^1-4. Here, we exploited CRISPR interference and programmable base editing to determine their potential in editing a TERT gene promoter-activating mutation, which occurs in many diverse cancer types, particularly glioblastoma^5-8. Correction of the -124C>T TERT promoter mutation to -124C was achieved using a single guide RNA (sgRNA)-guided and catalytically impaired Campylobacter jejuni CRISPR-associated protein 9-fused adenine base editor (CjABE). This modification blocked the binding of members of the E26 transcription factor family to the TERT promoter, reduced TERT transcription and TERT protein expression, and induced cancer-cell senescence and proliferative arrest. Local injection of adeno-associated viruses expressing sgRNA-guided CjABE inhibited the growth of gliomas harbouring TERT-promoter mutations. These preclinical proof-of-concept studies establish the feasibility of gene editing as a therapeutic approach for cancer and validate activated TERT-promoter mutations as a cancer-specific therapeutic target.

KAT2A succinyltransferase activity-mediated 14-3-3ζ upregulation promotes β-catenin stabilization-dependent glycolysis and proliferation of pancreatic carcinoma cells

Frequently occurring histone lysine succinylation is a newly identified histone modification that can be regulated by KAT2A histone succinyltransferase, which is also a histone acetyltransferase. KAT2A histone succinyltransferase activity is important for tumorigenesis; however, the mechanism underlying this tumor-promoting effect remains elusive. Here we demonstrate that KAT2A is highly expressed in human pancreatic ductal adenocarcinoma (PDAC) specimens and positively correlated with advanced stages of PDAC and short patients' survival. In addition, KAT2A expression in PDAC specimens is correlated with 14-3-3ζ expression, and KAT2A regulates H3K79 succinylation in the promoter region of YWHAZ (encoding for 14-3-3ζ) to promote YWHAZ mRNA and 14-3-3ζ expression, thereby preventing β-catenin degradation. Expression of succinyltransferase activity-defective KAT2A Y645A reduces H3K79 succinylation and 14-3-3ζ expression, leading to decreased β-catenin stability and subsequently decreased expression of cyclin D1, c-Myc, GLUT1, and LDHA. KAT2A-mediated 14-3-3ζ and β-catenin expression promotes glycolysis, cell proliferation, and migration and invasion of PDAC cells with epithelial-to-mesenchymal transition. These findings reveal a novel and instrumental role of KAT2A-mediated histone succinylation in regulation of gene expression and β-catenin stability to promote tumor cell proliferation and invasion.

The Abscopal Effect of Stereotactic Radiotherapy and Immunotherapy: Fool's Gold or El Dorado?

An 'abscopal' effect if often used to refer to distant tumour regression after localised irradiation. Since the first report of the abscopal effect in the 1950s, well-documented cases with radiotherapy alone are very rare. It is widely accepted that the immune response plays an important role in the abscopal effect, although the mechanism is still unclear. With the recent success of cancer immunotherapy, there is growing interest in combining immunotherapy with radiotherapy to boost abscopal response rates. Compared with conventional radiotherapy, stereotactic ablative radiotherapy (SABR) not only delivers ablative dose to the tumour, but may also induce robust immune responses. In this review we examine studies that combine SABR and immunotherapy. We review the preclinical rationale for SABR and immunotherapy combinations, the case for and against abscopal effects, and the current landscape of clinical trials.

[Exploration on developing the diagnosis and treatment guidelines for osteoarthritis in primary care of China]

At present, several clinical practice guidelines for osteoarthritis have been developed. Although contradictions about some recommendations are still in dispute, large number of clinical practice guidelines recommended core treatments, namely education, weight loss and exercise therapy. Thus, the diagnosis and treatment of primary osteoarthritis should focus on the above three treatments. However, we have to develop the clinical practice guidelines for osteoarthritis in primary hospital, based on the characteristics of osteoarthritis in China, the burden of disease, the health literacy of patients and the clinical decision-making of diagnosis and treatment of primary osteoarthritis in primary medical care.We suggest to formulate guidelines for the diagnosis and treatment of osteoarthritis in primary medical care to regulate primary interventions.

Micropatterned biodegradable polyesters clicked with CQAASIKVAV promote cell alignment, directional migration, and neurite outgrowth

The interplay of microstructures and biological cues is critical to regulate the behaviors of Schwann cells (SCs) in terms of cellular spatial arrangement and directional migration as well as neurite orientation for bridging the proximal and distal stumps of the injured peripheral nervous system. In this study, stripe micropatterns having ridges/grooves of width 20/20 and 20/40 μm were fabricated on the surface of maleimide-functionalized biodegradable poly(ester carbonate) (P(LLA-MTMC)) films by the polydimethylsiloxane mold-pressing method, respectively. The laminin-derived CQAASIKVAV peptides end-capped with an SH group were then grafted by the thiol-ene click reaction under mild conditions to obtain micropatterned and peptide-grafted films. SCs cultured on these films, especially on the 20/40-μm film, displayed faster and aligned adhesion as well as a larger number of elongated cells with a higher length-to-width (L/W) ratio along the stripe direction than those on the flat-pep film. The migration rate of SCs was significantly enhanced in parallel to the stripe direction with a large net displacement. The micropatterned and peptide-grafted films, especially the 20/40-μm film, could promote SC proliferation and nerve growth factor (NGF) secretion in a manner similar to that of the peptide-grafted planar film. Moreover, the neurites of rat pheochromocytoma 12 (PC12) cells sprouted along the ridges with a longer average length on the micropatterned and peptide-grafted films. The synergistic effect of physical patterns and biological cues was evaluated by considering the results of cell adhesion force; immunofluorescence staining of vinculin; fluorescence staining of F-actin and the nucleus; as well as gene expression of neural cadherin (NCAD), neurocan (NCAN), and myelin protein zero (P0).

STATEMENT OF SIGNIFICANCE

The interplay of microstructures and biological cues is critical to regulate the behaviors of Schwann cells (SCs) and nerve cells, and thereby the regeneration of peripheral nerve system. In this study, the combined micropatterning and CQAASIKVAV grafting endowed the modified P(LLA-MTMC) films with both contact guidance and bioactive chemical cues to enhance cell proliferation, directional alignment and migration, longer net displacement and larger NGF secretion, and stronger neurite outgrowth of SCs and PC12 cells. Hence, the integration of physical micropatterns and bioactive molecules is an effective way to obtain featured biomaterials for the regeneration of nerves and other types of tissues.

Intra-articular injection of mesenchymal stem cells in treating knee osteoarthritis: a systematic review of animal studies

PURPOSE

Mesenchymal stem cells (MSCs) injection has emerged as a novel treatment for knee osteoarthritis (KOA) but with inconsistent results in the experimental studies. Thus, the purpose of the present study is to evaluate the preclinical animal studies of MSCs injection for KOA and to determine the evidence for a role for MSCs in further clinical trials.

METHODS

A systematic search of KOA animal studies published through Aug 2017 was conducted using the PubMed, Embase and Web of science. Criteria for eligibility were animal studies assessing the therapeutic effects of MSCs intra-articular injection to animals with KOA. The methodological quality of included studies was assessed by the SYRCLE tool for assessing risk of bias in animal intervention studies. Descriptive synthesis was performed. Evidence quality was evaluated based on the Confidence in the Evidence from Reviews of Qualitative research (CERQual) tool.

RESULTS

Twenty-three KOA animal studies were eligible for inclusion. According to the SYRCLE's tool, all included studies had high risk of bias. Between-study heterogeneity was substantial. The included studies varied in terms of species, modeling methods, MSCs origin, treatment timing, injections frequency, transplantation type and dose of MSCs. The following outcomes, gross morphology, histological analysis, immunohistochemical analysis, radiological evaluation or behavior analysis, were reported in the primary studies. For all outcomes, the evidence quality was low or very low.

CONCLUSIONS

We do not have absolute confidence to recommend use MSCs injection for KOA clinical trials. Based on the internal and external validity of current animal studies, high quality experimental studies and efforts for effective translation from preclinical studies to clinical trials are still required.

KAT2A coupled with the α-KGDH complex acts as a histone H3 succinyltransferase

Histone modifications, such as the frequently occurring lysine succinylation, are central to the regulation of chromatin-based processes. However, the mechanism and functional consequences of histone succinylation are unknown. Here we show that the α-ketoglutarate dehydrogenase (α-KGDH) complex is localized in the nucleus in human cell lines and binds to lysine acetyltransferase 2A (KAT2A, also known as GCN5) in the promoter regions of genes. We show that succinyl-coenzyme A (succinyl-CoA) binds to KAT2A. The crystal structure of the catalytic domain of KAT2A in complex with succinyl-CoA at 2.3 Å resolution shows that succinyl-CoA binds to a deep cleft of KAT2A with the succinyl moiety pointing towards the end of a flexible loop 3, which adopts different structural conformations in succinyl-CoA-bound and acetyl-CoA-bound forms. Site-directed mutagenesis indicates that tyrosine 645 in this loop has an important role in the selective binding of succinyl-CoA over acetyl-CoA. KAT2A acts as a succinyltransferase and succinylates histone H3 on lysine 79, with a maximum frequency around the transcription start sites of genes. Preventing the α-KGDH complex from entering the nucleus, or expression of KAT2A(Tyr645Ala), reduces gene expression and inhibits tumour cell proliferation and tumour growth. These findings reveal an important mechanism of histone modification and demonstrate that local generation of succinyl-CoA by the nuclear α-KGDH complex coupled with the succinyltransferase activity of KAT2A is instrumental in histone succinylation, tumour cell proliferation, and tumour development.