Isolation of bone marrow mesenchymal stem cells in transgenic pigs and co-culture with porcine islets / 器官移植

Objective To investigate the isolation and culture of porcine bone marrow mesenchymal stem cell (BMSC) with α-1, 3-galactosyltransferase (GGTA1) gene knockout (GTKO), GTKO/ human CD46 (hCD46) insertion and cytidine monopho-N-acetylneuraminic acid hydroxylase (CMAH)/GGTA1 gene knockout (Neu5GC/Gal), and the protective effect of co-culture with porcine islets on islet cells. Methods Bone marrow was extracted from different transgenic pigs modified with GTKO, GTKO/hCD46 and Neu5GC/Gal. Porcine BMSC were isolated by the whole bone marrow adherent method and then cultured. The morphology of BMSC was observed and the surface markers of BMSC were identified by flow cytometry. Meantime, the multi-directional differentiation induced by BMSC was observed, and the labeling and tracing of BMSC were realized by green fluorescent protein (GFP) transfection. The porcine BMSC transfected with GFP were co-cultured with porcine islet cells. Morphological changes of porcine islet cells were observed, and compared with those in the porcine islet cell alone culture group. Results BMSC derived from pigs were spindle-shaped in vitro, expressing biomarkers of CD29, CD44, CD73, CD90, CD105 and CD166 rather than CD34 and CD45. These cells were able to differentiate into adipocytes, osteoblasts and chondrocytes. Porcine BMSC with GFP transfection could be labeled and traced, which could be stably expressed in the daughter cells after cell division. Porcine BMSC exerted certain protective effect on islet cells. Conclusions GFP-labeled porcine BMSC modified with GTKO, GTKO/hCD46 and Neu5GC/Gal are successfully established, which exert certain protective effect upon islet cells.

Alpha-synuclein dynamics bridge Type-I Interferon response and SARS-CoV-2 replication in peripheral cells

BACKGROUND: Increasing evidence suggests a double-faceted role of alpha-synuclein (α-syn) following infection by a variety of viruses, including SARS-CoV-2. Although α-syn accumulation is known to contribute to cell toxicity and the development and/or exacerbation of neuropathological manifestations, it is also a key to sustaining anti-viral innate immunity. Consistently with α-syn aggregation as a hallmark of Parkinson's disease, most studies investigating the biological function of α-syn focused on neural cells, while reports on the role of α-syn in periphery are limited, especially in SARS-CoV-2 infection. RESULTS: Results herein obtained by real time qPCR, immunofluorescence and western blot indicate that α-syn upregulation in peripheral cells occurs as a Type-I Interferon (IFN)-related response against SARS-CoV-2 infection. Noteworthy, this effect mostly involves α-syn multimers, and the dynamic α-syn multimer:monomer ratio. Administration of excess α-syn monomers promoted SARS-CoV-2 replication along with downregulation of IFN-Stimulated Genes (ISGs) in epithelial lung cells, which was associated with reduced α-syn multimers and α-syn multimer:monomer ratio. These effects were prevented by combined administration of IFN-ß, which hindered virus replication and upregulated ISGs, meanwhile increasing both α-syn multimers and α-syn multimer:monomer ratio in the absence of cell toxicity. Finally, in endothelial cells displaying abortive SARS-CoV-2 replication, α-syn multimers, and multimer:monomer ratio were not reduced following exposure to the virus and exogenous α-syn, suggesting that only productive viral infection impairs α-syn multimerization and multimer:monomer equilibrium. CONCLUSIONS: Our study provides novel insights into the biology of α-syn, showing that its dynamic conformations are implicated in the innate immune response against SARS-CoV-2 infection in peripheral cells. In particular, our results suggest that promotion of non-toxic α-syn multimers likely occurs as a Type-I IFN-related biological response which partakes in the suppression of viral replication. Further studies are needed to replicate our findings in neuronal cells as well as animal models, and to ascertain the nature of such α-syn conformations.

Salmonella enterica subsp. enterica serovar Typhimurium and Lactobacillus spp. interactions in vitro elicit improved antimicrobial production

@#Antimicrobial resistance (AMR) is a global health crisis. Despite the drug discovery efforts, AMR is increasing, and discoveries are nearly nil. It is thus critical to design new strategies. Probiotics are tapped as alternatives to antibiotics for the treatment of gut-associated diseases. Lactobacillus species, common in food products, can inhibit the growth of gut pathogens. Here, we demonstrate the antimicrobial activities of Lactobacillus species – Lactobacillus paracasei, Lactobacillus casei, and Lactobacillus delbrueckii subsp. bulgaricus are enhanced when cocultured with Salmonella enterica subsp. enterica serovar Typhimurium. Cell-free culture supernatants (CFCS) from cocultures of Lactobacillus spp. and Salmonella enterica serovar Typhimurium more potently inhibit pathogen growth than their monoculture counterparts. Interestingly, we discovered that Salmonella enterica serovar Typhimurium could enhance the production of antimicrobials from Lactobacillus spp., most evident in L. delbrueckii subsp. bulgaricus. Also, L. delbrueckii subsp. bulgaricus CFCS upregulates key Salmonella virulence genes, hilA and sipA. Whether this increases Salmonella’s pathogenicity in vivo or reduces pathogen fitness and growth inhibition in vitro warrants further investigation. We propose that these probiotic isolates may be utilized for innovative natural food processing and preservation strategies to control Salmonella food contaminations. Importantly, our findings that Salmonella elicits an enhanced antimicrobial activity from Lactobacillus spp. provide evidence of a pathogen-mediated elicitation of antimicrobial production. Therefore, extending this phenomenon to other microbial interactions may help augment the strategies for drug discovery.

Progress in antitumor effect of tumor-associated macrophages in co-culture system / 中华微生物学和免疫学杂志

Macrophages are important cells of the immune system. Tumor-associated macrophages are enriched macrophages near tumor cells or tissues. Their role is mainly to promote the construction of tumor inflammatory microenvironment and inhibit tumor immune response. Cell co-culture system is a symbiotic culture system formed by mimicking the internal environment of the body in vitro. The co-culture condition is relatively consistent with the environment in vivo, enabling better information exchange and material exchange between cells, which is a supplement to the monolayer cell culture and animal experiments. Tumor-associated macrophages and tumor cells co-exist in the tumor microenvironment. Thus, constructing a co-culture system for tumor-associated macrophages and tumor cells would be conducive to studying the antitumor effect of tumor-associated macrophages and developing new immunotherapy drugs. The co-culture system would provide a new direction for treating malignant tumors. This article mainly reviewed the co-culture patterns of macrophages and the antitumor effects of different phenotypes of macrophages, and highlighted the importance of using immunotherapy to treat malignant tumors in the tumor microenvironment.

Effect of stem cell factor on the angiogenic ability of cocultured DPSCs and HUVECs / 口腔疾病防治

Objective@#To study the effect of stem cell factor (SCF) on the angiogenic ability of cocultured dental pulp stem cells (DPSCs) and human umbilical vein endothelial cells (HUVECs).@*Methods @#This study has been reviewed and approved by the Ethics Committee. The experiment was split into the HUVECs, SCF+HUVECs, DPSCs+HUVECs, and SCF+DPSCs+HUVECs groups. A mixture of SCF and culture medium was used to prepare a mixed culture medium with an SCF concentration of 100 ng/mL. In vitro coculture of DPSCs and HUVECs was performed at a 1∶5 ratio. CCK-8 proliferation assay was used to observe the proliferative capacity of cells in each group on days 1, 3, 5, and 7. Wound healing and Transwell migration assays were used to detect the effect of SCF on cell migration under either direct or indirect coculture conditions, respectively. In vitro angiogenesis experiments were performed to detect the angiogenic capacity of the cells in each group. The vascular endothelial growth factor A (VEGFA) concentration in the cell culture supernatant was detected using ELISAs, and the protein expression levels of CD31, CD34, and VEGFA were detected using Western blot analysis. @*Results @# Wound healing and Transwell migration experiments showed that SCF significantly promoted the migration of cocultured DPSCs and HUVECs (P<0.05). The in vitro angiogenesis experiment showed that the number of branches and the total length of branches of tubular structures in the SCF+DPSCs+HUVECs group were significantly greater than those of the other groups (P<0.05), and the expression levels of the vascular-related proteins CD31, CD34, and VEGFA in this group were greater (P<0.01). @*Conclusion @# SCF can enhance the migration and in vitro angiogenesis of cocultured DPSCs and HUVECs.

Identification of the metabolites from co-cultures of marine Streptomyces sp. IMB18-531 and Cladosporium sp. IMB19-099 / 药学学报

A new siderophore chelate (1) and 8 known compounds were identified from the liquid co-cultures of the marine-derived Streptomyces sp. IMB18-531 and Cladosporium sp. IMB19-099 by a combination of chromatography methods, including C18 reversed-phase medium pressure chromatography, gel column chromatography and HPLC. Their structures were determined by spectroscopic analysis and chemical methods as aluminioxamine E (1), desferrioxamine E (2), ferrioxamine E (3), terragine E (4), capsimicin (5), cyclo(L-prolinyl-L-tyrosine) (6), anthranilic acid (7), (Z)-14-methylpentadec-9-enoic acid (8), and (Z)-hexadec-8-enoic acid (9). Compound 2 showed inhibitory activities against the expression of liver fibrosis related genes COL1A1, MMP2, and TIMP2. Compounds 5, 8, and 9 displayed antibacterial activities against methicillin-resistant Staphylococcus aureus, S. epidermidis and Bacillus subtilis, with MICs of 16-64 μg·mL-1. Compound 5 showed cytotoxicities against human pancreatic cancer MIA Paca-2 and human colon cancer HT-29 cell lines with IC50 of 2.9 and 6.3 μmol·L-1, respectively.

Effect of Angelica dahurica coumarins on the transport behavior of puerarin across blood-brain barrier in vitro and in vivo / 药学学报

A BBB co-culture cell model consisting of rat brain microvascular endothelial cells (BMEC) and astrocytes (AS) was established to study the effect of Angelica dahurica coumarins on the transport behavior of puerarin across blood-brain barrier (BBB) in vitro and in vivo. The barrier function of this model was evaluated by measuring the transendothelial resistance, phenol red permeability and BBB related protein expression. The permeability assay and western blot methods were performed to study the effects of Angelica dahurica coumarins on the BBB permeability and the expression of BBB related protein. The animal experiment protocols in this study were approved by the Animal Ethics Committee of Xi'an Jiaotong University (Animal Ethics No.: 2021-1329). The results showed that the established BMEC/AS co-culture model could be used to evaluate drug transport across BBB in vitro. After combined with Angelica dahurica coumarins, the transport capacity of puerarin was significantly increased in vitro and in vivo. Additionally, Angelica dahurica coumarins enhanced BBB permeability and inhibited the protein expression of P-glycoprotein (P-gp), zonula occludens-1 (ZO-1) and occludin. Angelica dahurica coumarins might increase BBB permeability by inhibiting the expression of P-gp and tight junction protein, thereby increasing the content of puerarin in brain tissue.

Application progress of air-liquid interface exposure technology in respiratory system toxicity induced by diesel exhaust in vitro / 环境与职业医学

Diesel exhaust (DE) is an important pollution source widely existing in the living and production environment, which is closely related to the health of the public and occupational groups. The International Agency for Research on Cancer has classified DE as a Group 1 carcinogen. Considering the negative health impacts on the respiratory system due to DE exposure in vitro, it is crucial to apply reliable test systems allowing accurate assessment of the biological effects of DE. The exposure technology of respiratory system in vitro is considered as one of the feasible measures to implement the 3R (reduce, refine, and replace) principle in animal experiments. Compared with the traditional submerged culture in vitro models, the air-liquid interface (ALI) exposure technology has the advantages including fewer influencing factors, easier exposure condition control, and shorter exposure cycle. ALI has become an important tool to study molecular events associated with physiology and pathology of respiratory system, and action modes and interactions of different cell types. Also, ALI has been increasingly widely used because it can simulate the actual processes of human respiratory system cells and/or tissues to DE exposure. This review was intended to introduce the development and advantages of ALI exposure technology, and further summarized the application progress of ALI exposure technology in studying the respiratory toxicity induced by DE exposure in vitro, so as to provide new ideas and pathways for the use of ALI exposure technology in the study of biomarkers and mechanisms of respiratory toxicity associated with DE exposure, and provide basic data to screen and promote biomarkers for exposed populations.

Detection of Calreticulin as a Candidate Prognostic Biomarker in Invasive Breast Carcinoma from a Biological Scaffold-Based 3D Co-culture System

@#Introduction: Breast cancer is the most common cancer in women and the world’s second leading cause of death in women, after lung cancer. Calreticulin (CRT), an endoplasmic reticulum (ER) multipurpose protein, has been proposed as a potential biomarker for breast cancer. However, reports on the correlation between CRT expression and cell invasiveness in breast cancer micro-tissues are scarce. Thus, in the current study, we analyzed the potential correlation between CRT and invasiveness of breast cancer in a biological scaffold-based 3D co-culture system. Methods: MCF7, MDA-MB-231 and MCF-10A breast cell lines were co-cultured in a 3-dimensional (3D) system with MRC-5 lung fibroblast cell line in the cell density ratio of 3:1. Thereafter, calreticulin gene and protein expression levels were determined based on quantitative reverse transcription-polymerase chain reaction (RT-qPCR) and immunohistochemistry, respectively. Moreover, via RT-qPCR analysis, the gene expression levels of calreticulin-related candidate metastasis genes in breast cancer micro-tissues were carried out. Results: The results showed occasional foci of lumen-like morphology in the non-cancerous breast micro-tissues and the formation of solid clusters for breast cancer micro-tissues. Moreover, immunohistochemistry results revealed protein expression of calreticulin in non-cancerous and cancerous breast micro-tissues with cytoplasmic and nucleic acid localizations. It was found that PCMT1 and ER-α genes were significantly downregulated (p < 0.01) in invasive breast cancer micro-tissues. Conclusion: This study suggests that CRT and CRT-related candidate metastasis genes may potentially serve as prognostic biomarkers in invasive breast carcinoma.

Structural diversification of bioactive bibenzyls through modular co-culture leading to the discovery of a novel neuroprotective agent

Bibenzyls, a kind of important plant polyphenols, have attracted growing attention for their broad and remarkable pharmacological activities. However, due to the low abundance in nature, uncontrollable and environmentally unfriendly chemical synthesis processes, these compounds are not readily accessible. Herein, one high-yield bibenzyl backbone-producing Escherichia coli strain was constructed by using a highly active and substrate-promiscuous bibenzyl synthase identified from Dendrobium officinale in combination with starter and extender biosynthetic enzymes. Three types of efficiently post-modifying modular strains were engineered by employing methyltransferases, prenyltransferase, and glycosyltransferase with high activity and substrate tolerance together with their corresponding donor biosynthetic modules. Structurally different bibenzyl derivatives were tandemly and/or divergently synthesized by co-culture engineering in various combination modes. Especially, a prenylated bibenzyl derivative ( 12) was found to be an antioxidant that exhibited potent neuroprotective activity in the cellular and rat models of ischemia stroke. RNA-seq, quantitative RT-PCR, and Western-blot analysis demonstrated that 12 could up-regulate the expression level of an apoptosis-inducing factor, mitochondria associated 3 (Aifm3), suggesting that Aifm3 might be a new target in ischemic stroke therapy. This study provides a flexible plug-and-play strategy for the easy-to-implement synthesis of structurally diverse bibenzyls through a modular co-culture engineering pipeline for drug discovery.

Cholinergic dysfunction-induced insufficient activation of alpha7 nicotinic acetylcholine receptor drives the development of rheumatoid arthritis through promoting protein citrullination via the SP3/PAD4 pathway

Both cholinergic dysfunction and protein citrullination are the hallmarks of rheumatoid arthritis (RA), but the relationship between the two phenomena remains unclear. We explored whether and how cholinergic dysfunction accelerates protein citrullination and consequently drives the development of RA. Cholinergic function and protein citrullination levels in patients with RA and collagen-induced arthritis (CIA) mice were collected. In both neuron-macrophage coculture system and CIA mice, the effect of cholinergic dysfunction on protein citrullination and expression of peptidylarginine deiminases (PADs) was assessed by immunofluorescence. The key transcription factors for PAD4 expression were predicted and validated. Cholinergic dysfunction in the patients with RA and CIA mice negatively correlated with the degree of protein citrullination in synovial tissues. The cholinergic or alpha7 nicotinic acetylcholine receptor (α7nAChR) deactivation and activation resulted in the promotion and reduction of protein citrullination in vitro and in vivo, respectively. Especially, the activation deficiency of α7nAChR induced the earlier onset and aggravation of CIA. Furthermore, deactivation of α7nAChR increased the expression of PAD4 and specificity protein-3 (SP3) in vitro and in vivo. Our results suggest that cholinergic dysfunction-induced deficient α7nAChR activation, which induces the expression of SP3 and its downstream molecule PAD4, accelerating protein citrullination and the development of RA.

iPSCs ameliorate hypoxia-induced autophagy and atrophy in C2C12 myotubes via the AMPK/ULK1 pathway

BACKGROUND: Duchenne muscular dystrophy (DMD) is an X-linked lethal genetic disorder for which there is no effective treatment. Previous studies have shown that stem cell transplantation into mdx mice can promote muscle regeneration and improve muscle function, however, the specific molecular mechanisms remain unclear. DMD suffers varying degrees of hypoxic damage during disease progression. This study aimed to investigate whether induced pluripotent stem cells (iPSCs) have protective effects against hypoxia-induced skeletal muscle injury. RESULTS: In this study, we co-cultured iPSCs with C2C12 myoblasts using a Transwell nested system and placed them in a DG250 anaerobic workstation for oxygen deprivation for 24 h. We found that iPSCs reduced the levels of lactate dehydrogenase and reactive oxygen species and downregulated the mRNA and protein levels of BAX/BCL2 and LC3II/ LC3I in hypoxia-induced C2C12 myoblasts. Meanwhile, iPSCs decreased the mRNA and protein levels of atrogin-1 and MuRF-1 and increased myotube width. Furthermore, iPSCs downregulated the phosphorylation of AMPKA and ULK1 in C2C12 myotubes exposed to hypoxic damage. CONCLUSIONS: Our study showed that iPSCs enhanced the resistance of C2C12 myoblasts to hypoxia and inhibited apoptosis and autophagy in the presence of oxidative stress. Further, iPSCs improved hypoxia-induced autophagy and atrophy of C2C12 myotubes through the AMPK/ULK1 pathway. This study may provide a new theoretical basis for the treatment of muscular dystrophy in stem cells.

Study on the differentiation of rat bone marrow mesenchymal stem cells into islet-like cell masses under co-culture conditions / 中华胰腺病杂志

Objective:To examine the possibility of the differentiation into islet-like cell clusters from the co-culture system of bone marrow mesenchymal stem cells (BMSCs) and islet cells.Methods:Rat BMSCs from the femur and tibia of Wistar rats were isolated and purified taken under aseptic conditions; the surface markers CD 44 and CD 90 expressions of BMSCs were detected by flow cytometry; and alizarin red staining and oil red O staining were used to identify the cells induced in the osteogenic direction and adipogenic direction, respectively. Rat islet cells from the pancreas of Wistar rats were isolated and purified; and dithiazone staining was performed for validation. The basal insulin level of the culture was detected by ELISA method. 5.6mmol/L (low glucose) and 25.0 mmol/L (high glucosa) glucose were added to the culture, respectively, and insulin release was detected by ELISA. 5-generation BMSCs and islet cells were collected and divided randomly into stem cell culture alone group (stem cell group), stem cell-islet co-culture group (co-culture group), and islet culture alone group (islet group). The morphological changes of BMSCs during co-culture were observed using an inverted phase contrast microscope; basal insulin secretion and insulin secretion stimulated by low and high glucose were tested by ELISA. Insulin protein expression in induced islet-like cell masses in co-culture group were detected by immunocytochemical staining. The ultrastructure of islet-like cells was observed by using transmission electron microscopy. Results:The positive rates of CD 44 and CD 90 were 99.48% and 99.50%, respectively; BMSCs were induced the formation of multiple calcium nodules outside the differentiation cells in the osteogenic direction, and many lipid droplets in the cytoplasm of differentiated cells in the adipogenic direction. Dithiazone staining showed that β cells in pancreatic islet were brown red and about 450 islets could be obtained per pancreas with a mean purity up to 80%. The insulin release in the low sugar group and the high sugar group were (7.105±1.551) mIU/ml and (20.231±1.592) mIU/ml, respectively, with a statistically significant difference ( P<0.05). It can be seen that local stem cells began to gather and grow upward into small clumps in the budding manner until finally forming a spherical islet-like cell cluster structure after 7 days of culture in the co-culture group. The basal insulin secretion in the stem cell group was <0.5 mIU/L. In the islet group, insulin secretion peaked on the 5th day and then gradually decreased to about 20% of the highest value on the 13th day. The insulin level of the co-culture group peaked on the 5th day, and the 13th day remained at about 40% of the peak level. There were statistically significant differences on basal insulin secretion on the 8th, 10th and 13th day between islet group and co-culture group (all P value >0.05). There was no statistically significant difference between the insulin release by islet in islet group under the stimulation of low and high sugar and that by islet-like cell cluster in co-culture group. There were a large number of brownish-yellow granules in the islet-like cell clusters after the co-culture for 14 days; and there were more secretory granules and coarse endoplasmic reticulum in the ultrastructure, showing more active protein secretion functions. Conclusions:The co-culture system of BMSCs and islet cells could induce BMSCs into differentiating into islet-like cell clusters, which can express insulin protein and had relatively mature function of insulin secretion.

A study on keloid fibroblast induced THP-1 derived macrophage polarization and inflammatory factor TNF-αexpression and its feedback effect / 中华医学美学美容杂志

Objective:To investigate the effect of keloid fibroblasts on the polarization and expression of inflammatory factors of M0 macrophages and possible mechanisms, and provide theoretical basis for new targets for keloid therapy.Methods:Keloids, normal skin tissues and paraffin specimens from patients undergoing plastic surgery in the First Affiliated Hospital of Sun Yat-sen University from November 2020 to September 2021 were collected, and fibroblasts of keloids and normal skins were isolated and co-cultured with M0 cells formed form THP-1 by phorbol ester (PMA)-stimulation to detect the expression of macrophage polarization markers and cytokines. Besides, keloid fibroblasts were treated with exogenous tumor necrosis factor-α(TNF-α) to detect its effect on the proliferation and extracellular matrix expression.Results:Macrophages were dominated by CD163 + (M2) in keloid tissues. Moreover, M0 cells expressed more TNF-α when co-cultured with keloid fibroblasts, compared with those with normal skin fibroblasts, in which, the positive staining rates of TNF-α were 19.32% and 29.52% respectively by flow cytometry. Furthermore, the proliferation was promoted and the expression of extracellular matrix proteins (COL3A1 and FN1)and Vimentin were upregulated in keloid fibroblasts under TNF-α stimulation. However, there was no significant difference in the expression of polarization surface markers CD86 and CD163 in macrophages, when co-cultured with keloid fibroblasts or normal skin fibroblasts. Conclusions:Keloid fibroblasts promote the expression of TNF-α in macrophages, which in turn promotes the proliferation and extracellular matrix secretion of keloid fibroblasts.

Effect of HaCaT cells with CRISPR-Cas9-induced KRT5 mutation on co-cultured human melanocytes / 中华皮肤科杂志

Objective:To investigate the effect of KRT5 knockdown in keratinocytes on melanin content in co-cultured melanocytes, and to explain mechanisms underlying formation of hyperpigmented lesions in reticulate pigmented anomaly of the flexures (Dowling-Degos disease, DDD) .Methods:HaCaT cells with heterozygous mutations in the KRT5 gene were obtained by using clustered regularly interspaced short palindromic repeats (CRISPR) -CRISPR-associated protein 9 (Cas9) technology (experimental group) , and HaCaT cells transfected with non-targeting single guide RNA:Cas9 protein complex served as control group, both of which were in vitro co-cultured with primary human melanocyte cells (HEMn) separately. Immunofluorescence study was conducted to determine the expression of cytokeratin and melanosomes in co-cultured cells; melanin content was detected in melanocytes in different co-culture groups, which were obtained by differential trypsinization. Immunohistochemical study was performed to determine the expression of melanocyte-specific premelanosome protein 17 (Pmel17) in skin lesions in a patient with DDD carrying a KRT5 mutation and normal skin tissues in a healthy control. Results:Sanger sequencing showed a heterozygous mutation (c.1delA) at the initiation codon of exon 1 of the KRT5 gene in HaCaT cells in the experimental group, but no mutation in the KRT5 gene in the control group. Western blot analysis showed that the KRT5 protein expression was significantly lower in the experimental group (0.60 ± 0.05) than in the control group (1.00 ± 0.00, t = 32.38, P = 0.001) . Compared with the co-culture system in the control group, the number of Pmel17-labeled melanosomes markedly increased with the melanin content elevated by 52.5% ( t = -3.48, P = 0.025) in the HEMn cells co-cultured with HaCaT cells in the experimental group. Immunohistochemical study showed that the Pmel17 expression increased in the skin lesions in the DDD patient with KRT5 mutation compared with the normal skin tissues in the healthy control. Conclusion:The effect of HaCaT cells with CRISPR-Cas9-induced KRT5 mutation on the co-cultured HEMn melanocytes was verified by the successfully established in vitro co-culture system, which provides a primary cell model for further studies on interaction mechanisms between keratinocytes and melanocytes, and on pathogenesis of skin pigmentation abnormalities.

Construction of a neuroinflammation model: a microglia-neuron co-culture system / 中华麻醉学杂志

Objective:To develop an in vitro neuroinflammation model by establishing a microglia-neuron co-culture system. Methods:Mouse microglia (BV-2), motor neurons (NSC34) and hippocampal neurons (HT-22) were selected.This experiment was performed in two parts.Experiment Ⅰ BV-2 microglia were stimulated with different concentrations of lipopolysaccharide (LPS, 10, 100, 500 and 1 000 ng/ml). Microglia culture supernatant(Conditioned Medium) was extracted and two types of neurons were cultured separately.The concentration of LPS that resulted in a significant 50% decrease in neuronal viability was selected using the CCK-8 method for establishment of the Transwell co-culture system.Experiment Ⅱ Microglia were cultured in the upper chamber of Transwell, and neurons were seeded in the lower chamber.Microglia were divided into 2 groups ( n=12 each) using the random number table method: control group and LPS group.In control group and LPS group, microglia were cultured for 6 h with cell culture medium and LPS, respectively, then the medium was replaced with fresh medium, microglia were continuously incubated for 12 h, and then the cells in the upper and lower chambers were combined.The cells were incubated using the BV-2-NSC34 Transwell co-culture system for 12 h and using the BV-2-HT-22 Transwell co-culture system for 24 h. The concentrations of interleukin-1beta (IL-1β) and IL-18 in neuronal culture supernatant were measured by enzyme-linked immunosorbent assay, the apoptotic rate of neurons was determined by flow cytometry, the expression of Bcl-2 and Bax mRNA in neurons was detected by quantitative real-time polymerase chain reaction, and the expression of cleaved caspase-3, Bcl-2 and Bax in neurons was detected by Western blot. Results:Experiment Ⅰ LPS concentration for stimulation was 10 ng/ml in BV-2-NSC34 Transwell co-culture system and 1, 000 ng/ml in BV-2-HT-22 Transwell co-culture system.Experiment Ⅱ Compared with control group, the concentrations of IL-1β and IL-18 and apoptotic rate of neurons were significantly increased, Bax protein and mRNA expression was up-regulated, Bcl-2 protein and mRNA expression was down-regulated, and cleaved caspase-3 expression was up-regulated in LPS group ( P<0.05 or 0.01). Conclusions:The microglia-neuron co-culture system is successfully established by the conditioned medium technique and Transwell co-culture system, which provides an experimental protocol for establishment of neuroinflammation models associated with postoperative cognitive dysfunction.

Application and population control strategy of microbial modular co-culture engineering / 生物工程学报

Traditional methods of microbial synthesis usually rely on a single engineered strain to synthesize the target product through metabolic engineering. The key cofactors, precursors and energy are produced by the introduced complex synthetic pathways. This would increase the physiological burden of engineering strains, resulting in a decrease in the yield of target products. The modular co-culture engineering has become an attractive solution for effective heterologous biosynthesis, where product yield can be greatly improved. In the modular co-culture engineering, the coordination between the population of different modules is essential for increasing the production efficiency. This article summarized recent advances in the application of modular co-culture engineering and population control strategies.

Advances in the co-culture of microalgae with other microorganisms and applications / 生物工程学报

Intense utilization and mining of fossil fuels for energy production have resulted in environmental pollution and climate change. Compared to fossil fuels, microalgae is considered as a promising candidate for biodiesel production due to its fast growth rate, high lipid content and no occupying arable land. However, monocultural microalgae bear high cost of harvesting, and are prone to contamination, making them incompetent compared with traditional renewable energy sources. Co-culture system induces self-flocculation, which may reduce the cost of microalgae harvesting and the possibility of contamination. In addition, the productivity of lipid and high-value by-products are higher in co-culture system. Therefore, co-culture system represents an economic, energy saving, and efficient technology. This review aims to highlight the advances in the co-culture system, including the mechanisms of interactions between microalgae and other microorganisms, the factors affecting the lipid production of co-culture, and the potential applications of co-culture system. Finally, the prospects and challenges to algal co-culture systems were also discussed.

Using OMICS technologies to analyze the mechanisms of synthetic microbial co-culture systems: a review / 生物工程学报

In recent years, the interaction mechanisms underpinning the synthetic microbial co-culture systems have gained increasing attention due to their potentials in various biotechnological applications. Exploration of the inter-species mechanisms underpinning the synthetic microbial co-culture system could contribute to a better understanding of the theoretical basis to further optimize the existing co-culture systems, and design new synthetic co-culture system for large-scale application. OMICS technologies such as genomics, transcriptomics, proteomics, and metabolomics could analyze the biological processes in a high throughput manner. Multi-omics analysis could achieve a "global view" of various members in the microbial co-culture systems, which presents opportunities in understanding synthetic microbial consortia better. This article summarizes recent advances in understanding the mechanisms of synthetic microbial co-culture systems using omics technologies, from the aspects of metabolic network, energy metabolism, signal transduction, membrane transport, stress response, community stability and structural rationality. All these findings could provide important theoretical basis for future application of the microbial co-culture systems with the aids of emerging biotechnologies such as synthetic biology and genome editing.

Production of lactate from carbon fixation by cyanobacteria: development and prospect / 生物工程学报

Lactate is an important industrial chemical and widely used in various industries. In recent years, with the increasing demand for polylactic acid (PLA), the demand for lactate raw materials is also increasing. The contradiction between the high cost and the market demand caused by the heterotrophic production of lactate attracts researchers to seek other favorable solutions. The production of lactate from photosynthetic carbon fixation by cyanobacteria is a potential new raw material supply strategy. Based on the photosynthetic autotrophic cell factory, it can directly produce high optical purity lactate from carbon dioxide on a single platform driven by solar energy. The raw materials are cheap and easy to obtain, the process is simple and controllable, the products are clear and easy to separate, and the double effects of energy saving and emission reduction and production of high value-added products are achieved at the same time, which has important research and application value. This paper reviews the development history of cyanobacteria carbon sequestration to produce lactate, summarizes its research progress and encounters technical difficulties from the aspects of metabolic basis, metabolic engineering strategy, metabolic kinetics analysis and technical application, and prospects the future of this technology.