Halogenated organic compounds are persistent pollutants that pose a serious threat to human health and the safety of ecosystems. Cobamides are essential cofactors for reductive dehalogenases (RDase) in organohalide-respiring bacteria (OHRB), which catalyze the dehalogenation process. This review systematically summarizes the impact of cobamides on organohalide respiration. The catalytic processes of cobamide in dehalogenation processes are also discussed. Additionally, we examine OHRB, which cannot synthesize cobamide and must obtain it from the environment through a salvage pathway; the co-culture with cobamide producer is more beneficial and possible. This review aims to help readers better understand the importance and function of cobamides in reductive dehalogenation. The presented information can aid in the development of bioremediation strategies.

Macrophages, as the largest immune cell group in tumour tissues, play a crucial role in influencing various malignant behaviours of tumour cells and tumour immune evasion. As the research on macrophages and cancer immunotherapy develops, the importance of appropriate research models becomes increasingly evident. The development of organoids has bridged the gap between traditional two-dimensional (2D) cultures and animal experiments. Recent studies have demonstrated that organoids exhibit similar physiological characteristics to the source tissue and closely resemble the in vivo genome and molecular markers of the source tissue or organ. However, organoids still lack an immune component. Developing a co-culture model of organoids and macrophages is crucial for studying the interaction and mechanisms between tumour cells and macrophages. This paper presents an overview of the establishment of co-culture models, the current research status of organoid macrophage interactions, and the current status of immunotherapy. In addition, the application prospects and shortcomings of the model are explained. Ultimately, it is hoped that the co-culture model will offer a preclinical testing platform for maximising a precise cancer immunotherapy strategy.

OBJECTIVE: Osteosarcoma is a primary bone tumor lacking optimal clinical treatment options. Tumor-associated macrophages in the tumor microenvironment are closely associated with tumor development and metastasis. Studies have identified the macrophage receptor with collagenous structure (MARCO) as a specific receptor expressed in macrophages. This study aimed to investigate whether anti-MARCO mAb treatment can induce macrophage polarization in the tumor microenvironment and elicit anti-tumor effects.
METHODS: THP-1 cells were treated with 20 ng/mL phorbol 12-myristate 13-acetate and 80 ng/mL interleukin-4 for 48 h to induce macrophage polarization to alternatively activated macrophages (M2). Enzyme-linked immunosorbent assay, real-time quantitative polymerase chain reaction, flow cytometry, and bioinformatic analyses were performed to evaluate macrophage polarization. The co-culture groups included a blank group, an M2 macrophage and U2OS co-culture group, and an anti-MARCO mAb-treated M2 macrophage group. Cell viability assays, cell scratch tests, apoptosis, and cell cycle analyses were performed to determine the effects of anti-MARCO mAb-treated macrophages on osteosarcoma cells.
RESULTS: It was demonstrated that anti-MARCO mAb can drive macrophages toward classically activated macrophage (M1) polarization. Anti-MARCO mAb promoted the secretion of pro-inflammatory factors by macrophages, including tumor necrosis factor-alpha (TNF-α), interleukin-1beta, interleukin-6 and interleukin-23. Studies on in vitro co-culture models have revealed that macrophages treated with anti-MARCO mAb can suppress the growth and migration of osteosarcoma cells, induce cell apoptosis, and inhibit cell cycle progression of osteosarcoma cells through M1 polarization of macrophages in vitro.
CONCLUSIONS: Anti-MARCO mAb treatment exerts anti-osteosarcoma effects by affecting macrophage polarization toward M1 macrophages, offering a potential new therapeutic approach for treating osteosarcoma.

Combined-cultures involving mycolic acid-containing bacteria (MACB) can stimulate secondary metabolite (SM) production in actinomycetes. In a prior investigation, we screened Streptomyces coelicolor JCM4020 mutants with diminished production of SMs, specifically undecylprodigiosin (RED), which was enhanced by introducing the MACB Tsukamurella pulmonis TP-B0596. In this study, we conducted mutational analysis that pinpointed the sco1842 gene, which we assigned the gene name ccr1 (combined-culture related regulatory protein no. 1), as a crucial factor in the deficient phenotype observed in the production of various major SMs in S. coelicolor A3(2). Notably, the Ccr1 (SCO1842) homolog was found to be highly conserved throughout the Streptomyces genome. Although Ccr1 lacked conserved motifs, in-depth examination revealed the presence of a helix-turn-helix (HTH) motif in the N-terminal region and a helicase C-terminal domain (HCTD) motif in the C-terminal region in some of its homologs. Ccr1 was predicted to be a nucleoid-associated protein (NAP), and its impact on gene transcription was validated by RNA-seq analysis that revealed genome-wide variations. Furthermore, RT-qPCR demonstrated that ccr1 was transcriptionally activated in combined-culture with T. pulmonis, which indicated that Ccr1 is involved in the response to bacterial interaction. We then investigated Streptomyces nigrescens HEK616 in combined-culture, and the knockout mutant of the ccr1 homolog displayed reduced production of streptoaminals and 5aTHQs. This finding reveals that the Ccr1 homolog in Streptomyces species is associated with SM production. Our study elucidates the existence of a new family of NAP-like proteins that evolved in Streptomyces species and play a pivotal role in SM production.

Impairment of the intestinal epithelial barrier is frequently seen as collateral damage in various local and systemic inflammatory conditions. The inflammatory process is characterized by reciprocal interactions between the host intestinal epithelium and mucosal innate immune cells, e.g., macrophages. This article provides step-by-step instructions on how to set up a murine enteroid-macrophage co-culture by culturing cellular elements in proximity separated by a porous membrane. Unlike previously published co-culture systems, we have combined enteroids grown from C57BL6j mice with syngeneic bone marrow-derived macrophages to preclude potential allo-reactions between immune cells and epithelium. Transformation of intestinal crypts into proliferative enteroids was achieved by cultivation in Wnt3a-Noggin-R-Spondin-conditioned medium supplemented with ROCK inhibitor Y-27632. The differentiated phenotype was promoted by the use of the Wnt3-deprived EGF-Noggin-R-Spondin medium. The resulting co-culture of primary cells can be employed as a basic model to better understand the reciprocal relationship between intestinal epithelium and macrophages. It can be used for in vitro modelling of mucosal inflammation, mimicked by stimulation of macrophages either while being in co-culture or before being introduced into co-culture, to simulate enterogenic sepsis or systemic conditions affecting the intestinal tract.

The marine Streptomyces harbor numerous biosynthetic gene clusters (BGCs) with exploitable potential. However, many secondary metabolites cannot be produced under laboratory conditions. Co-culture strategies of marine microorganisms have yielded novel natural products with diverse biological activities. In this study, we explored the metabolic profiles of co-cultures involving Streptomyces sp. 2-85 and Cladosporium sp. 3-22-derived from marine sponges. Combining Global Natural Products Social (GNPS) Molecular Networking analysis with natural product database mining, 35 potential antimicrobial metabolites annotated were detected, 19 of which were exclusive to the co-culture, with a significant increase in production. Notably, the Streptomyces-Fungus interaction led to the increased production of borrelidin and the discovery of several analogs via molecular networking. In this study, borrelidin was first applied to combat Saprolegnia parasitica, which caused saprolegniosis in aquaculture. We noted its superior inhibitory effects on mycelial growth with an EC50 of 0.004 mg/mL and on spore germination with an EC50 of 0.005 mg/mL compared to the commercial fungicide, preliminarily identifying threonyl-tRNA synthetase as its target. Further analysis of the associated gene clusters revealed an incomplete synthesis pathway with missing malonyl-CoA units for condensation within this strain, hinting at the presence of potential compensatory pathways. In conclusion, our findings shed light on the metabolic changes of marine Streptomyces and fungi in co-culture, propose the potential of borrelidin in the control of aquatic diseases, and present new prospects for antifungal applications.

The tumor microenvironment (TME) includes immune and stromal cells and noncellular extracellular matrix (ECM) components. Tumor-associated macrophages (TAMs) are the most important immune cells in TME and are crucial for carcinomas\' progression. The purpose was to analyze direct and indirect interactions in co-culture of tumor cells with monocytes/macrophages and, additionally, to indicate which interactions are more important for cancer development. Cytokines, reactive oxygen species, nitric oxide level, tumor cell cycle and changes in tumor cell morphology after human tumor cells (Hep-2 and RK33 cell lines) with human monocyte/macrophage (THP-1 cell line) interactions were tested. Morphology and cytoskeleton organization of tumor cells did not change after co-culture with macrophages. In co-culture of tumor cells with human monocyte, changes in the percentage of tumor cells in cell cycle phases was observed. No significant changes in reactive oxygen species (ROS) were found in the co-culture as compared to the tumor cell mono-culture. Monocytes produced about three times higher ROS than tumor cells. In co-cultures, a lower nitric oxide (NOx) level was found as compared to the sum of the production by both mono-cultures. Co-culture conditions limited the production of cytokines (IL-4, IL-10 and IL-13) as compared to the sum of their level in mono-cultures. In conclusion, macrophages influence tumor cell growth and functions. Mutual (direct and paracrine) interactions between tumor cells and macrophages changed cytokine production and tumor cell cycle profile. The data obtained may allow us to initially indicate which kind of interactions may have a greater impact on cancer development processes.

Cell co-culture technology aims to study the communication mechanism between cells and to better reveal the interactions and regulatory mechanisms involved in processes such as cell growth, differentiation, apoptosis, and other cellular activities. This is achieved by simulating the complex organismic environment. Such studies are of great significance for understanding the physiological and pathological processes of multicellular organisms. As an emerging cell cultivation technology, 3D cell co-culture technology, based on microfluidic chips, can efficiently, rapidly, and accurately achieve cell co-culture. This is accomplished by leveraging the unique microchannel structures and flow characteristics of microfluidic chips. The technology can simulate the native microenvironment of cell growth, providing a new technical platform for studying intercellular communication. It has been widely used in the research of oncology, immunology, neuroscience, and other fields. In this review, we summarize and provide insights into the design of cell co-culture systems on microfluidic chips, the detection methods employed in co-culture systems, and the applications of these models.

Saikosaponin D (SSd) is a naturally active product with strong pharmacological activity found in Bupleurum scorzonerifolium Willd. Studies have shown that endophytic fungi have great potential as sources of natural medicines. Fusarium acuminatum (CHS3), an SSd-producing endophytic fungus, was isolated from B. scorzonerifolium. To elucidate the effect of host plants on the production of SSd in CHS3, CHS3 was co-cultured with suspension cells of B. scorzonerifolium and SSd was detected using high-performance liquid chromatography (HPLC). Transcriptome sequencing (RNA-Seq) of CHS3 before and after co-culture was performed using an Illumina HiSeq 2500 platform. The results indicated that the content of SSd synthesised by CHS3 increased after co-culture with suspension cells of B. scorzonerifolium. Transcriptome analysis of CHS3 with differentially expressed genes (DEGs) showed that 1202 and 1049 genes were upregulated and downregulated, respectively, after co-culture. Thirty genes associated with SSd synthesis and 11 genes related to terpene backbone biosynthesis were annotated to the Kyoto Encyclopaedia of Genes and Genomes (KEGG). Combined with transcriptome data, it was speculated that the mevalonate (MVA) pathway is a possible pathway for SSd synthesis in CHS3, and the expression of key enzyme genes (HMGR, HMGCS, GGPS1, MVK, FDFT1, FNTB) was validated by qRT-PCR. In conclusion, the endophytic fungus CHS3 can form an interactive relationship with its host, thereby promoting SSd biosynthesis and accumulation by upregulating the expression of key enzyme genes in the biosynthesis pathway.

Interactions between tissues and cell types, mediated by cytokines or direct cell-cell exchanges, regulate growth. To determine whether mature adipocytes influence the in vitro growth of trout mononucleated muscle cells, we developed an indirect coculture system, and showed that adipocytes (5 × 106 cells/well) derived from perivisceral adipose tissue increased the proliferation (BrdU-positive cells) of the mononucleated muscle cells (26% vs. 39%; p < 0.001) while inhibiting myogenic differentiation (myosin+) (25% vs. 15%; p < 0.001). Similar effects were obtained with subcutaneous adipose tissue-derived adipocytes, although requiring more adipocytes (3 × 107 cells/well vs. 5 × 106 cells/well). Conditioned media recapitulated these effects, stimulating proliferation (31% vs. 39%; p < 0.001) and inhibiting myogenic differentiation (32 vs. 23%; p < 0.001). Adipocytes began to reduce differentiation after 24 h, whereas proliferation stimulation was observed after 48 h. While adipocytes did not change pax7+ and myoD1/2+ percentages, they reduced myogenin+ cells showing inhibition from early differentiation stage. Finally, adipocytes increased BrdU+ cells in the Pdgfrα+ population but not in the myoD+ one. Collectively, our results demonstrate that trout adipocytes promote fibro-adipocyte precursor proliferation while inhibiting myogenic cells differentiation in vitro, suggesting the key role of adipose tissue in regulating fish muscle growth.