Astrocyte mitochondria: Potential therapeutic targets for epilepsy.

Epilepsy is a chronic, relapsing neurological disorder, and current treatments focus primarily on neurons, yet one-third of patients still develop drug-resistant epilepsy. Therefore, there is an urgent need to explore new therapeutic targets. Interestingly, astrocytes can transfer their healthy mitochondria into neighboring neurons, thus preventing neuronal damage. Astrocyte mitochondria have been shown to have a therapeutic role in stroke and neurodegenerative diseases. However, their therapeutic effect in epilepsy and its related mechanisms have been less studied. In this review, we mainly summarize the regulatory role of astrocyte mitochondria in glutamate, calcium ion, and adenosine triphosphate (ATP) homeostasis and outline the protective role of astrocyte mitochondria in nervous system diseases, revealing a new target for epilepsy treatment.

Association between Homologous Recombination Repair Defect Status and Long-Term Prognosis of Early HER2-Low Breast Cancer: A Retrospective Cohort Study.

BACKGROUND: As a newly identified subtype of HER2-negative tumors associated with a less favorable prognosis, it remains crucial to evaluate potential prognostic and predictive factors, particularly non-invasive biomarkers, for individuals with human epidermal growth factor 2 (HER2) low early-stage breast cancer (EBC). Multiple investigations have highlighted that HER2-negative patients with EBC exhibiting high homologous recombination deficiency (HRD) scores display lower rates of pathological complete response (PCR) to neoadjuvant chemotherapy (NAC). Nevertheless, no study to date has explored the correlation between HRD and the long-term prognosis in HER2-low patients with EBC. PATIENTS AND METHODS: This retrospective observational study focuses on primary EBC sourced from The Cancer Genome Atlas dataset (TCGA). It reveals the gene mutation landscape in EBC with low HER2 expression and elucidates the tumor immune landscape across different HRD states. Utilizing bioinformatics analysis and Cox proportional models, along with the Kaplan-Meier method, the study assesses the correlation between HRD status and disease-specific survival (DSS), disease-free interval (DFI), and progression-free interval (PFI). Subgroup analyses were conducted to identify potential variations in the association between HRD and prognosis. RESULTS: In the patients with HER2-low breast cancer, patients with homologous recombination related genes (HRRGs) defects had an HRD score about twice that of those without related genes mutations, and were at higher risk of acquiring ARID1A, ATM, and BRCA2 mutations. We also found that most immune cell abundances were significantly higher in EBC tumors with high HRD than in EBC tumors with low HRD or HRD-medium, particularly plasma B-cell abundance, CD8 T-cell abundance, and M1 macrophages. In addition, these tumors with HRD-high also appear to have significantly higher tumor immune scores and lower interstitial scores. Then, we analyzed the relationship between different HRD status and prognosis. There was statistical significance (P = .036 and P = .046, respectively) in DSS and PFI between the HRD-low and HRD-high groups, and patients with HRD-high EBC showed relatively poor survival outcomes. A medium HRD score (hazard ratio, HR = 2.15, 95% CI: 1.04-4.41, P = .038) was a significant risk factor for PFI. Hormone receptor positivity is an important factor in obtaining medium-high HRD score and poor prognosis. CONCLUSION: Higher HRD scores were associated with poorer PFI outcomes, particularly in people with HR+/HER2-low. Varied HRD states exhibited distinctions in HRRGs and the tumor immune landscape. These insights have the potential to assist clinicians in promptly identifying high-risk groups and tailoring personalized treatments for patients with HER2-low EBC, aiming to enhance long-term outcomes.

Deciphering Depressor Anguli Oris for Lower Face Rejuvenation: A Prospective Ultrasound-Based Investigation.

BACKGROUND: The depressor anguli oris muscle (DAO) is a pivotal treatment target in creation of harmonic jawline. However, evidence of its live morphology remains scarce. OBJECTIVES: This study aimed to reevaluate DAO by a facile ultrasound analysis and hereby guide safer and more effective botulinum toxin type A (BTX-A) injection. METHODS: A prospective ultrasound assessment was conducted in 41 patients. Morphology of DAO and its relative position with neighboring structures were appraised at the ubiquitous facial landmark, labiomandibular fold (LMF). Three-dimensional images were captured before and after receiving BTX-A injection based on sonographic evidence. RESULTS: The skin-to-muscle depths of DAO on average (measured from the medial to lateral border) were 5.26, 5.61, and 8.42 mm. DAO becomes thinner and wider from zone 1 to 3 (p < 0.001). Overlapping lengths between DAO and DLI increased from zone 1 to 3: 4.74, 9.68, 14.54 mm (p < 0.001). The medial border of DAO was located at 4.33, 6.12, 8.90 mm medial to LMF (zone 1-3), and no muscle fibers of DAO was observed at zone 1 and 2 in near one-third of patients. Mouth corner downturn angle improvement upon receiving BTX-A injection at zone 2 and 3 were 88.3%, 32.3%, and 14.7% for the neutral, maximum smile, and down-pulling mouth corner expressions. CONCLUSIONS: This work established an informative ultrasound portrait of the DAO and structures in the perioral region, which suggests LMF as a convenient landmark to locate DAO. Injections at the middle and lower thirds of LMF at a 4-5 mm depth is recommended.

The crosstalk between epilepsy and dementia: A systematic review and meta-analysis.

BACKGROUND: Epilepsy and dementia are bidirectional. The purpose of this review was to investigate the epidemiological characteristics of and to identify the risk factors for epilepsy in patients with dementia and dementia in patients with epilepsy. METHODS: We retrieved the PubMed, Embase, Cochrane and Web of Science databases through January 2023. Two individuals screened the articles, extracted the data, and used a random effects model to pool the estimates and 95% confidence intervals (CIs). RESULTS: From 3475 citations, 25 articles were included. The prevalence of seizures/epilepsy was 4% among dementia patients and 3% among Alzheimer's disease (AD) patients. For vascular dementia, Lewy body dementia, and frontotemporal dementia, the pooled period prevalence of seizures/epilepsy was 6%, 3%, and 2%, respectively. Baseline early-onset AD was associated with the highest risk of 5-year epilepsy (pooled hazard ratios: 4.06; 95% CI: 3.25-5.08). Dementia patients had a 2.29-fold greater risk of seizures/epilepsy than non-dementia patients (95% CI: 1.37-3.83). Moreover, for baseline epilepsy, the pooled prevalence of dementia was 17% (95% CI: 10-25%), and that of AD was 15% (95% CI: 9-21%). The pooled results suggested that epilepsy is associated with a greater risk of dementia (risk ratio: 2.83, 95% CI: 1.64-4.88). CONCLUSIONS: There are still gaps in epidemiology regarding the correlation between dementia types and epilepsy, vascular risk factors, and the impact of antiseizure medication or cognitive improvement drugs on epilepsy and AD comorbidity.

Effect of lite touch on the anxiety of low-risk pregnant women in the latent phase of childbirth: a randomized controlled trial.

Introduction: Women with perinatal anxiety have reduced coping capacity during labor, which affects labor progress and increases the likelihood of a cesarean section. Several non-pharmacological interventions for anxiety during childbirth are available. This study used the "lite touch" method, a non-pharmacological intervention based on physiological responses and obstetric clinical experience in women. We aimed to evaluate whether lite touch could relieve perinatal anxiety and investigate the effect of light skin stroking on the maternal hormones, catecholamine, and cortisol. Methods: This randomized clinical trial involved women with low-risk singleton pregnancies at full term or near term. Eligible pregnant women who were latent and did not undergo epidural anesthesia were randomized into two groups. Participants in the intervention group underwent routine prenatal care, including lite touch, whereas the control group underwent routine prenatal care alone. Demographic data were collected through a questionnaire. Labor anxiety was assessed using the State Anxiety Inventory, and saliva was collected before and after the intervention. Changes in saliva cortisol and catecholamine levels were analyzed using a double-antibody sandwich enzyme-linked immunosorbent assay. Results: In total, 83 participants were included, with 43 and 40 in the intervention and control groups, respectively. In the intervention group, pre-intervention anxiety scores were significantly lower (p < 0.01) than post-intervention anxiety scores, whereas the control group showed no difference in anxiety scores before and after intervention (p > 0.05). Cortisol and catecholamine levels in saliva were significantly lower in the intervention group than in the control group after the intervention (p < 0.01). Discussion: Lite touch can reduce the latent anxiety state of low-risk pregnant women, thereby maintaining in vivo stability and facilitating labor. Clinical trial registration: https://www.chictr.org.cn/aboutEN.html, ChiCTR2300070905, Retrospectively Registered Date: April 26, 2023.

Selective Intracellular Delivery of Antibodies in Cancer Cells with Nanocarriers Sensing Endo/Lysosomal Enzymatic Activity.

The differential enzymatic activity in the endo/lysosomes of particular cells could trigger targeted endosomal escape functions, enabling selective intracellular protein delivery. However, this strategy may be jeopardized due to protein degradation during endosomal trafficking. Herein, using custom made fluorescent probes to assess the endosomal activity of cathepsin B (CTSB) and protein degradation, we found that certain cancer cells with hyperacidified endosomes grant a spatiotemporal window where CTSB activity surpass protein digestion. This inspired the engineering of antibody-loaded polymeric nanocarriers having CTSB-activatable endosomal escape ability. The nanocarriers selectively escaped from the endo/lysosomes in the cells with high endosomal CTSB activity and delivered active antibodies to intracellular targets. This study provides a viable strategy for cell-specific protein delivery using stimuli-responsive nanocarriers with controlled endosomal escape.

Amlodipine inhibits the proliferation and migration of esophageal carcinoma cells through the induction of endoplasmic reticulum stress.

BACKGROUND: L-type calcium channels are the only protein channels sensitive to calcium channel blockers, and are expressed in various cancer types. The Cancer Genome Atlas database shows that the mRNA levels of multiple L-type calcium channel subunits in esophageal squamous cell carcinoma tumor tissue are significantly higher than those in normal esophageal epithelial tissue. Therefore, we hypothesized that amlodipine, a long-acting dihydropyridine L-type calcium channel blocker, may inhibit the occurrence and development of esophageal cancer (EC). AIM: To investigate the inhibitory effects of amlodipine on EC through endoplasmic reticulum (ER) stress. METHODS: Cav1.3 protein expression levels in 50 pairs of EC tissues and corresponding paracancerous tissues were examined. Subsequently, the inhibitory effects of amlodipine on proliferation and migration of EC cells in vitro were detected using 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide and Transwell assays. In vivo experiments were performed using murine xenograft model. To elucidate the underlying mechanisms, in vitro cell studies were performed to confirm that ER stress plays a role in inhibition proliferation and migration of EC cells treated with amlodipine. RESULTS: The expression level of Cav1.3 in esophageal carcinoma was 1.6 times higher than that in paracancerous tissues. Amlodipine treatment decreased the viability of esophageal carcinoma cells in a dose- and time-dependent manner. In vivo animal experiments also clearly indicated that amlodipine inhibited the growth of EC tumors in mice. Additionally, amlodipine reduces the migration of tumor cells by inhibiting epithelial-mesenchymal transition (EMT). Mechanistic studies have demonstrated that amlodipine induces ER stress-mediated apoptosis and suppresses EMT. Moreover, amlodipine-induced autophagy was characterized by an increase in autophagy lysosomes and the accumulation of light chain 3B protein. The combination of amlodipine with the ER stress inhibitor 4-phenylbutyric acid further confirmed the role of the ER stress response in amlodipine-induced apoptosis, EMT, and autophagy. Furthermore, blocking autophagy increases the ratio of apoptosis and migration. CONCLUSION: Collectively, we demonstrate for the first time that amlodipine promotes apoptosis, induces autophagy, and inhibits migration through ER stress, thereby exerting anti-tumor effects in EC.

Identification of lipid synthesis genes in Schizochytrium sp. and their application in improving eicosapentaenoic acid synthesis in Yarrowia lipolytica.

BACKGROUND: Eicosapentaenoic acid (EPA) is widely used in the functional food and nutraceutical industries due to its important benefits to human health. Oleaginous microorganisms are considered a promising alternative resource for the production of EPA lipids. However, the storage of EPA in triglyceride (TG) becomes a key factor limiting its level. RESULTS: This study aimed to incorporate more EPA into TG storage through metabolic engineering. Firstly, key enzymes for TG synthesis, the diacylglycerol acyltransferase (DGAT) and glycerol-3-phosphate acyltransferase (GPAT) genes from Schizochytrium sp. HX-308 were expressed in Yarrowia lipolytica to enhance lipid and EPA accumulation. In addition, engineering the enzyme activity of DGATs through protein engineering was found to be effective in enhancing lipid synthesis by replacing the conserved motifs "HFS" in ScDGAT2A and "FFG" in ScDGAT2B with the motif "YFP". Notably, combined with lipidomic analysis, the expression of ScDGAT2C and GPAT2 enhanced the storage of EPA in TG. Finally, the accumulation of lipid and EPA was further promoted by identifying and continuing to introduce the ScACC, ScACS, ScPDC, and ScG6PD genes from Schizochytrium sp., and the lipid and EPA titer of the final engineered strain reached 2.25 ± 0.03 g/L and 266.44 ± 5.74 mg/L, respectively, which increased by 174.39% (0.82 ± 0.02 g/L) and 282.27% (69.70 ± 0.80 mg/L) compared to the initial strain, respectively. CONCLUSION: This study shows that the expression of lipid synthesis genes from Schizochytrium sp. in Y. lipolytica effectively improves the synthesis of lipids and EPA, which provided a promising target for EPA-enriched microbial oil production.

Association of FTH1-Expressing Circulating Tumor Cells With Efficacy of Neoadjuvant Chemotherapy for Patients With Breast Cancer: A Prospective Cohort Study.

BACKGROUND: The association between different phenotypes and genotypes of circulating tumor cells (CTCs) and efficacy of neoadjuvant chemotherapy (NAC) remains uncertain. This study was conducted to evaluate the relationship of FTH1 gene-associated CTCs (F-CTC) with/without epithelial-mesenchymal transition (EMT) markers, or their dynamic changes with the efficacy of NAC in patients with non-metastatic breast cancer. PATIENTS AND METHODS: This study enrolled 120 patients with non-metastatic breast cancer who planned to undergo NAC. The FTH1 gene and EMT markers in CTCs were detected before NAC (T0), after 2 cycles of chemotherapy (T1), and before surgery (T2). The associations of these different types of CTCs with rates of pathological complete response (pCR) and breast-conserving surgery (BCS) were evaluated using the binary logistic regression analysis. RESULTS: F-CTC in peripheral blood ≥1 at T0 was an independent factor for pCR rate in patients with HER2-positive (odds ratio [OR]=0.08, 95% confidence interval [CI], 0.01-0.98, P = .048). The reduction in the number of F-CTC at T2 was an independent factor for BCS rate (OR = 4.54, 95% CI, 1.14-18.08, P = .03). CONCLUSIONS: The number of F-CTC prior to NAC was related to poor response to NAC. Monitoring of F-CTC may help clinicians formulate personalized NAC regimens and implement BCS for patients with non-metastatic breast cancer.

Universal and unique strategies for the production of polyunsaturated fatty acids in industrial oleaginous microorganisms.

Polyunsaturated fatty acids (PUFAs), especially docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA) and arachidonic acid (ARA), are beneficial for reducing blood cholesterol and enhancing memory. Traditional PUFA production relies on extraction from plants and animals, which is unsustainable. Thus, using microorganisms as lipid-producing factories holds promise as an alternative way for PUFA production. Several oleaginous microorganisms have been successfully industrialized to date. These can be divided into universal and specialized hosts according to the products range of biosynthesis. The Yarrowia lipolytica is universal oleaginous host that has been engineered to produce a variety of fatty acids, such as γ-linolenic acid (GLA), EPA, ARA and so on. By contrast, the specialized host are used to produce only certain fatty acids, such as ARA in Mortierella alpina, EPA in Nannochloropsis, and DHA in Thraustochytrids. The metabolic engineering and fermentation strategies for improving PUFA production in universal and specialized hosts are different, which is the subject of this review. In addition, the widely applicable strategies for microbial lipid production that are not specific to individual hosts were also reviewed.

Enhancing the accumulation of lipid and docosahexaenoic acid in Schizochytrium sp. by co-overexpression of phosphopantetheinyl transferase and ω-3 fatty acid desaturase.

Docosahexaenoic acid (DHA) as one of ω-3 polyunsaturated fatty acids (PUFAs), plays a key role in brain development, and is widely used in food additives and the pharmaceutical industry. Schizochytrium sp. is often considered as a satisfactory strain for DHA industrialization. The aim of this study was to assess the feasibility of phosphopantetheinyl transferase (PPTase) and ω-3 fatty acid desaturase (FAD) for regulating DHA content in Schizochytrium sp. PPTase is essential to activate the polyketide-like synthase (PKS) pathway, which can transfer apo-acyl-carrier protein (apo-ACP) into holo-ACP, and plays a key role in DHA synthesis. Moreover, DHA and docosapentaenoic acid (DPA) are synthesized by the PKS pathway simultaneously, so high DPA synthesis limits the increase of DHA content. In addition, the detailed mechanisms of PKS pathway have not been fully elucidated, so it is difficult to improve DHA content by modifying PKS. However, ω-3 FAD can convert DPA into DHA, and it is the most direct and effective way to increase DHA content and reduce DPA content. Based on this, PPTase was overexpressed to enhance the synthesis of DHA by the PKS pathway, overexpressed ω-3 FAD to convert the co-product of the PKS pathway into DHA, and co-overexpressed PPTase and ω-3 FAD. With these strategies, compared with wild type, the final lipid, and DHA titer were 92.5 and 51.5 g L-1 , which increased by 46.4% and 78.1%, respectively. This study established an efficient DHA production strain, and provided some feasible strategies for industrial DHA production in Schizochytrium sp.

Structure-Activity Relationships, Tolerability and Efficacy of Microtubule-Active 1,2,4-Triazolo[1,5-a]pyrimidines as Potential Candidates to Treat Human African Trypanosomiasis.

Tubulin and microtubules (MTs) are potential protein targets to treat parasitic infections and our previous studies have shown that the triazolopyrimidine (TPD) class of MT-active compounds hold promise as antitrypanosomal agents. MT-targeting TPDs include structurally related but functionally diverse congeners that interact with mammalian tubulin at either one or two distinct interfacial binding sites; namely, the seventh and vinca sites, which are found within or between α,ß-tubulin heterodimers, respectively. Evaluation of the activity of 123 TPD congeners against cultured Trypanosoma brucei enabled a robust quantitative structure-activity relationship (QSAR) model and the prioritization of two congeners for in vivo pharmacokinetics (PK), tolerability and efficacy studies. Treatment of T. brucei-infected mice with tolerable doses of TPDs significantly decreased blood parasitemia within 24 h. Further, two once-weekly doses at 10 mg/kg of a candidate TPD significantly extended the survival of infected mice relative to infected animals treated with vehicle. Further optimization of dosing and/or the dosing schedule of these CNS-active TPDs may provide alternative treatments for human African trypanosomiasis.

Efficient Biosynthesis of Odd-Chain Fatty Acids via Regulating the Supply and Consumption of Propionyl-CoA in Schizochytrium sp.

Odd chain fatty acids (OCFAs) are high-value-added compounds with great application in the field of food and medicine. As an oleaginous microorganism, Schizochytrium sp. has the potential to produce OCFAs efficiently. Propionyl-CoA is used as a precursor to synthesize OCFAs through the fatty acid synthetase (FAS) pathway, so its flow direction determines the yield of OCFAs. Here, different substrates were assessed to promote propionyl-CoA supply for OCFA accumulation. Moreover, the methylmalonyl-CoA mutase (MCM) was identified as the key gene responsible for propionyl-CoA consumption, which promotes the propionyl-CoA to enter into the tricarboxylic acid cycle rather than the FAS pathway. As one of the classic B12-dependent enzymes, the activity of MCM can be inhibited in the absence of B12. As expected, the OCFA accumulation was greatly increased. However, the removal of B12 caused growth limitation. Furthermore, the MCM was knocked out to block the consumption of propionyl-CoA and to maintain cell growth; results showed that the engineered strain achieved the OCFAs titer of 2.82 g/L, which is 5.76-fold that of wild type. Last, a fed-batch co-feeding strategy was developed, resulting in the highest reported OCFAs titer of 6.82 g/L. This study provides guidance for the microbial production of OCFAs.

Enhancing the biomass and docosahexaenoic acid-rich lipid accumulation of Schizochytrium sp. in propionate wastewater.

In order to find a more effective way to obtain docosahexaenoic acid (DHA) rich lipid from Schizochytrium sp., a widespread propionate wastewater (PW) is used. PW is a common industrial and domestic wastewater, and transforming it into valuable products is a potential treatment method. Schizochytrium sp. is a rapidly growing oleaginous organism, which has been used commercially for DHA production. Herein, PW is completely used for DHA production by Schizochytrium sp. by genetic engineering and fermentation optimization, which can alleviate the increasingly tense demand for water resources and environmental pollution caused by industrial wastewater. Firstly, the methylmalonyl-CoA mutase (MCM) was overexpressed in Schizochytrium sp. to enhance the metabolism of propionate, then the engineered strain of overexpressed MCM (OMCM) can effectively use propionate. Then, the effects of PW with different concentration of propionate were investigated, and results showed that OMCM can completely replace clean water with PW containing 5 g L-1 propionate. Furthermore, in the fed-batch fermentation, the OMCM obtained the highest biomass of 113.4 g L-1 and lipid yield of 64.4 g L-1 in PW condition, which is 26.8% and 51.7% higher than that of wild type (WT) in PW condition. Moreover, to verify why overexpression of MCM can promote DHA and lipid accumulation, the comparative metabolomics, ATP production level, the antioxidant system, and the transcription of key genes were investigated. Results showed that ATP induced by PW condition could drive the synthesis of DHA, and remarkably improve the antioxidant capacity of cells by enhancing the carotenoids production. Therefore, PW can be used as an effective and economical substrate and water source for Schizochytrium sp. to accumulate biomass and DHA.

Repurposing pentamidine for cancer immunotherapy by targeting the PD1/PD-L1 immune checkpoint.

Immunotherapy has emerged as an effective therapeutic approach to several cancer types. The reinvigoration of tumor-infiltrating lymphocyte-mediated immune responses via the blockade of immune checkpoint markers, such as program cell death-1 (PD-1) or its cognate ligand PD-L1, has been the basis for developing clinically effective anticancer therapies. We identified pentamidine, an FDA-approved antimicrobial agent, as a small-molecule antagonist of PD-L1. Pentamidine enhanced T-cell-mediated cytotoxicity against various cancer cells in vitro by increasing the secretion of IFN-γ, TNF-α, perforin, and granzyme B in the culture medium. Pentamidine promoted T-cell activation by blocking the PD-1/PD-L1 interaction. In vivo administration of pentamidine attenuated the tumor growth and prolonged the survival of tumor-bearing mice in PD-L1 humanized murine tumor cell allograft models. Histological analysis of tumor tissues showed an increased number of tumor-infiltrating lymphocytes in tissues derived from pentamidine-treated mice. In summary, our study suggests that pentamidine holds the potential to be repurposed as a novel PD-L1 antagonist that may overcome the limitations of monoclonal antibody therapy and can emerge as a small molecule cancer immunotherapy.

Electrocatalytic Synthesis of Essential Amino Acids from Nitric Oxide Using Atomically Dispersed Fe on N-doped Carbon.

How to transfer industrial exhaust gases of nitrogen oxides into high-values product is significantly important and challenging. Herein, we demonstrate an innovative method for artificial synthesis of essential α-amino acids from nitric oxide (NO) by reacting with α-keto acids through electrocatalytic process with atomically dispersed Fe supported on N-doped carbon matrix (AD-Fe/NC) as the catalyst. A yield of valine with 32.1 µmol mgcat -1 is delivered at -0.6 V vs. reversible hydrogen electrode, corresponding a selectivity of 11.3 %. In situ X-ray absorption fine structure and synchrotron radiation infrared spectroscopy analyses show that NO as nitrogen source converted to hydroxylamine that promptly nucleophilic attacked on the electrophilic carbon center of α-keto acid to form oxime and subsequent reductive hydrogenation occurred on the way to amino acid. Over 6 kinds of α-amino acids have been successfully synthesized and gaseous nitrogen source can be also replaced by liquid nitrogen source (NO3 - ). Our findings not only provide a creative method for converting nitrogen oxides into high-valued products, which is of epoch-making significance towards artificial synthesis of amino acids, but also benefit in deploying near-zero-emission technologies for global environmental and economic development.

Enhanced docosahexaenoic acid production from cane molasses by engineered and adaptively evolved Schizochytrium sp.

Cane molasses (CM) is a sugar-rich agro-industrial byproduct. The purpose of this study is to synthesize docosahexaenoic acid (DHA) in Schizochytrium sp. by using CM. The single factor analysis showed that sucrose utilization was the main factor limiting the utilization of CM. Therefore, the endogenous sucrose hydrolase (SH) was overexpressed in Schizochytrium sp., which enhanced the sucrose utilization rate 2.57-fold compared to the wild type. Furthermore, adaptive laboratory evolution was used to further improve sucrose utilization from CM. Comparative proteomics and RT-qPCR were used out to analyze the metabolic differences of evolved strain grown on CM and glucose, respectively. Finally, a constant flow rate CM feeding strategy was implemented, whereby the DHA titer and lipid yield of the final strain OSH-end reached 25.26 g/L and 0.229 g/g sugar, respectively. This study demonstrated the CM is a cost-effective carbon source for industrial DHA fermentation.

ANGPTL2 binds MAG to efficiently enhance oligodendrocyte differentiation.

BACKGROUND: Oligodendrocytes have robust regenerative ability and are key players in remyelination during physiological and pathophysiological states. However, the mechanisms of brain microenvironmental cue in regulation of the differentiation of oligodendrocytes still needs to be further investigated. RESULTS: We demonstrated that myelin-associated glycoprotein (MAG) was a novel receptor for angiopoietin-like protein 2 (ANGPTL2). The binding of ANGPTL2 to MAG efficiently promoted the differentiation of oligodendrocytes in vitro, as evaluated in an HCN cell line. Angptl2-null mice had a markedly impaired myelination capacity in the early stage of oligodendrocyte development. These mice had notably decreased remyelination capacities and enhanced motor disability in a cuprizone-induced demyelinating mouse model, which was similar to the Mag-null mice. The loss of remyelination ability in Angptl2-null/Mag-null mice was similar to the Angptl2-WT/Mag-null mice, which indicated that the ANGPTL2-mediated oligodendrocyte differentiation effect depended on the MAG receptor. ANGPTL2 bound MAG to enhance its phosphorylation level and recruit Fyn kinase, which increased Fyn phosphorylation levels, followed by the transactivation of myelin regulatory factor (MYRF). CONCLUSION: Our study demonstrated an unexpected cross-talk between the environmental protein (ANGPTL2) and its surface receptor (MAG) in the regulation of oligodendrocyte differentiation, which may benefit the treatment of many demyelination disorders, including multiple sclerosis.

Block catiomers with flanking hydrolyzable tyrosinate groups enhance in vivo mRNA delivery via π-π stacking-assisted micellar assembly.

Messenger RNA (mRNA) therapeutics have recently demonstrated high clinical potential with the accelerated approval of SARS-CoV-2 vaccines. To fulfill the promise of unprecedented mRNA-based treatments, the development of safe and efficient carriers is still necessary to achieve effective delivery of mRNA. Herein, we prepared mRNA-loaded nanocarriers for enhanced in vivo delivery using biocompatible block copolymers having functional amino acid moieties for tunable interaction with mRNA. The block copolymers were based on flexible poly(ethylene glycol)-poly(glycerol) (PEG-PG) modified with glycine (Gly), leucine (Leu) or tyrosine (Tyr) via ester bonds to generate block catiomers. Moreover, the amino acids can be gradually detached from the block copolymers after ester bond hydrolyzation, avoiding cytotoxic effects. When mixed with mRNA, the block catiomers formed narrowly distributed polymeric micelles with high stability and enhanced delivery efficiency. Particularly, the micelles based on tyrosine-modified PEG-PG (PEG-PGTyr), which formed a polyion complex (PIC) and π-π stacking with mRNA, displayed excellent stability against polyanions and promoted mRNA integrity in serum. PEG-PGTyr-based micelles also increased the cellular uptake and the endosomal escape, promoting high protein expression both in vitro and in vivo. Furthermore, the PEG-PGTyr-based micelles significantly extended the half-life of the loaded mRNA after intravenous injection. Our results highlight the potential of PEG-PGTyr-based micelles as safe and effective carriers for mRNA, expediting the rational design of polymeric materials for enhanced mRNA delivery.