Effects of selected flavonoids on cell proliferation and differentiation of porcine muscle stem cells for cultured meat production

Antifungal and antibiofilm activities of flavonoids against Candida albicans: Focus on 3,2'-dihydroxyflavone as a potential therapeutic agent

Effective management of microbial biofilms holds significance within food and medical environments. Candida albicans, an opportunistic fungus, forms mucosal biofilms closely linked to candidiasis and drug-resistant infections due to their drug tolerance. Morphologic change from yeast to filamentous cells is a key virulence factor and a prerequisite for biofilm development. This study investigated the anti-fungal and antibiofilm activities of 20 flavonoids against C. albicans. With their known antioxidant capabilities, flavonoids hold promise in combating infections associated with biofilms. Among them, flavone and its derivatives exhibited moderate antifungal activity, 3,2'-dihydroxyflavone (3,2'-DHF) at 1 μg/mL exhibited strong antibiofilm activity (MIC 50 μg/mL). In addition, 3,2'-DHF dramatically inhibited cell aggregation and germ tube/hyphae formation. Transcriptomic analyses revealed that flavone and 3,2'-DHF behaved differently, as 3,2'-DHF downregulated the expressions of germ tube/hyphae-forming and biofilm-related genes (ECE1, HWP1, TEC1, and UME6) but upregulated the biofilm/hyphal regulators (CHK1, IFD6, UCF1, and YWP1). Tests evaluating toxicity with plant and nematode models revealed that flavone and 3,2'-DHF exhibited mild toxicity. Current results indicate that hydroxylated flavone derivatives can enhance anti-fungal and antibiofilm activities and provide a source of potential anti-fungal agents against drug-resistant C. albicans.

Transcriptomic analysis reveals the inhibitory effect of beta-sitosterol on proliferation of bovine preadipocytes

Fat deposition affects beef quantity and quality via preadipocyte proliferation. Beta-sitosterol, a natural small molecular compound, has various functions, such as anti-inflammation, antibacterial, and anticancer properties. The mechanism of action of Beta-sitosterol on bovine preadipocytes remains unclear. This study, based on RNA-seq, reveals the impact of Beta -sitosterol on the proliferation of bovine preadipocytes. Compared to the control group, Beta-sitosterol demonstrated a more pronounced inhibitory effect on cell proliferation after 48 hours of treatment than after 24 hours, as evidenced by the results of EdU staining and flow cytometry. RNA-seq and Western Blot analyses further substantiated these findings. Our results suggest that the impact of Beta-sitosterol on the proliferation of bovine preadipocytes is not significant after a 24-hour treatment. It is only after extending the treatment time to 48 hours that Beta-sitosterol may induce cell cycle arrest at the G2/M phase by suppressing the expression of CCNB1, thereby inhibiting the proliferation of bovine preadipocytes.

Responsible innovation: Mitigating the food safety aspects of cultured meat production

There is much interest in cultured (cultivated) meat as a potential solution to concerns over the ecological and environmental footprint of food production, especially from animal-derived food products. The aim of this critical review is to undertake a structured analysis of existing literature to (i) identify the range of materials that could be used within the cultured meat process; (ii) explore the potential biological and chemical food safety issues that arise; (iii) identify the known and also novel aspects of the food safety hazard portfolio that will inform hazard analysis and risk assessment approaches, and (iv) position a responsible innovation framework that can be utilized to mitigate food safety concerns with specific emphasis on cultured meat. Although a number of potential food safety hazards are identified that need to be considered within a food safety plan, further research is required to validate and verify that these food safety hazards have been suitably controlled and, where possible, eliminated. The responsible innovation framework developed herein, which extends beyond hazard analysis and traditional risk assessment approaches, can be applied in multiple contexts, including this use case of cultured meat production.

Antibiofilm and Antivirulence Potentials of 3,2'-Dihydroxyflavone against Staphylococcus aureus

Staphylococcus aureus, particularly drug-resistant strains, poses significant challenges in healthcare due to its ability to form biofilms, which confer increased resistance to antibiotics and immune responses. Building on previous knowledge that several flavonoids exhibit antibiofilm activity, this study sought to identify a novel flavonoid capable of effectively inhibiting biofilm formation and virulence factor production in S. aureus strains including MRSA. Among the 19 flavonoid-like compounds tested, 3,2'-dihydroxyflavone (3,2'-DHF) was identified for the first time as inhibiting biofilm formation and virulence factors in S. aureus with an MIC 75 µg/mL. The antibiofilm activity was further confirmed by microscopic methods. Notably, 3,2'-DHF at 5 µg/mL was effective in inhibiting both mono- and polymicrobial biofilms involving S. aureus and Candida albicans, a common co-pathogen. 3,2'-DHF reduces hemolytic activity, slime production, and the expression of key virulence factors such as hemolysin gene hla and nuclease gene nuc1 in S. aureus. These findings highlight the potential of 3,2'-DHF as a novel antibiofilm and antivirulence agent against both bacterial and fungal biofilms, offering a promising alternative to traditional antibiotics in the treatment of biofilm-associated infections.

Analysis of current technology status for the industrialization of cultured meat

Cultured meat is expected to become an important material for future food production; however, contrary to initial expectations, the full-scale industrialization of cultured meat is slow and the actual level and opened technology amount is very limited. This study reviews the publicly available technologies of cultured meat and suggests future developmental directions and research agenda. As a result of analyzing papers, patents, and press releases published over the past 10 years, it was found that cultured meat production technology is still at the prototype production level. This is because most papers published are about culture medium and scaffold development, culture conditions, and there is almost no research on finished cultured meat products. Worldwide, most of the filed patents are for producing cultured meat principles; most of them do not use food-grade materials and are not economically feasible for industrialization. Therefore, future research on the industrialization of cultured meat should focus on effective acquisition technologies for satellite cells; cell lineage and undifferentiated state maintenance technologies; the development of serum-free media and culture devices; the prevention of genetic modification, safety verification, and mass production. Furthermore, basic research on mechanisms and influencing factors related to cultured meat production is warranted.

Metabolomic changes in culture media with varying passage numbers of pig muscle stem cell culture for cultured meat production

Selecting the primary cells in an optimal state for cultured meat production is a crucial challenge in commercializing cultured meat. We investigated the metabolomic changes in culture media according to passage numbers for indirectly assessing the state of primary cells. Pig skeletal muscle stem cells (PSCs) harvested from the biceps femoris muscles of 7-d-old crossbred pigs (Landrace × Yorkshire × Duroc, LYD) were used for cell characterization. Fresh media (FM) and spent media (SM) of PSCs during passages 1 to 3 in vitro culture were prepared for metabolomics analysis. SM was collected on the third day of proliferation for each passage of PSCs. Cell characterization analysis revealed that the proliferation rate was highest at passage 2; however, a significant loss of expression of myogenic marker genes was observed at passage 3. Based on metabolomic profiles of culture media, FM and SM groups (SM1, SM2, and SM3) were clearly separated by partial least squares-discriminant analysis. A total of seven differentially abundant metabolites (DAMs) were identified from FM and SM for each passage, based on the following criteria: P < 0.05, fold change > 1.5 or < 0.66, and a variable importance in projection score > 1.5. All seven DAMs and their interconnected metabolites might be primarily used as substrates for energy production and most of them were relatively abundant in SM3. Among the seven DAMs, the three potential biomarkers (γ-glutamyl-L-leucine, cytosine, and ketoleucine), which showed significant changes exclusively in SM3, each had an area under the curve value of 1. Therefore, monitoring the levels of these key metabolites in culture media could serve as a quality control measure for cultured meat production by enabling the indirect detection of suboptimal PSCs based on their proliferation ability.

Effect of Crude Polysaccharides from Ecklonia cava Hydrolysate on Cell Proliferation and Differentiation of Hanwoo Muscle Stem Cells for Cultured Meat Production

Ecklonia cava, a brown seaweed native to the East Asian coast, is known for its unique composition, including polysaccharides, polyphenols, and phlorotannins. Fucoidan is a sulfated polysaccharide widely used as a functional ingredient in foods. This study obtained crude polysaccharides (ECC_CPS) from E. cava celluclast enzymatic hydrolysate using ethanol precipitation. ECC_CPS increased cell viability during the proliferation of Hanwoo muscle satellite cells (HMSCs). The effect of ECC_CPS on the expression of proliferation-related markers was confirmed as MYF5 and MYOD expression significantly increased, whereas PAX7 expression was maintained. The evaluation of cell migration activity has a major impact on cell proliferation and differentiation, and the cell migration index significantly increased with ECC_CPS treatment (p < 0.01). This was related to the HGF/MET pathway and FAK pathway. Treatment with ECC_CPS promoted differentiation at the cell differentiation stage, thereby increasing the expression of differentiation markers, such as MYH2, MYH7, and MYOG (p < 0.001 or p < 0.01). Therefore, our findings imply that crude polysaccharide obtained from E. cava can be an additive ingredient that enhances the proliferation and differentiation of muscle satellite cells used in the manufacture of cultured meat products.

Selected flavonoids exhibit antibiofilm and antibacterial effects against Vibrio by disrupting membrane integrity, virulence and metabolic activities

Vibrio parahaemolyticus is a high-risk foodborne pathogen associated with raw or undercooked seafoods and its biofilm forming potential has become a threat to food safety and economic values. Hence, this study aims to examine the antibacterial and antibiofilm activities as well as virulence inhibitory effects of selected flavonoids against V. parahaemolyticus. Out of the sixteen flavonoid derivatives, 6-aminoflavone (6-AF), 3,2-dihydroxyflavone (3,2-DHF) and 2,2-dihydroxy-4-methoxybenzophenone (DHMB) were found as active biofilm inhibitors. 3,2-DHF and DHMB had minimum inhibitory concentrations of 20 and 50 μg/mL respectively against Vibrio planktonic cells and displayed superior antibacterial activities to standard controls. Also, they disrupted preformed biofilms and suppressed virulence properties including motilities, cell hydrophobicity and aggregation. They impaired iron acquisition mechanism and hemolysin production at sub-MICs as supported by transcriptomic studies. Interestingly, the flavonoids interfered with the metabolic activity, cell division and membrane permeability to exert antibiofilm and antibacterial activities. 6-AF and 3,2-DHF were non-toxic in the C. elegans model and showed excellent capacity to protect shrimps from biodeterioration. Furthermore, the flavonoids inhibited biofilm formation by V. harveyi, Staphylococcus aureus and Salmonella typhimurium and the mixed-species biofilm with Vibrio. This study discovered flavonoid derivatives, especially 3,2-DHF as potential bioactive compounds capable of offering protection from risks associated with biofilm formation by V. parahaemolyticus and other food pathogens.

Morphology-Based Prediction of Proliferation and Differentiation Potencies of Porcine Muscle Stem Cells for Cultured Meat Production

Inconsistent efficiency of cell production caused by cellular quality variations has become a significant problem in the cultured meat industry. In our study, morphological information on passages 5-9 of porcine muscle stem cells (pMuSCs) from three lots was analyzed and used as input data in prediction models. Cell proliferation and differentiation potencies were measured by cell growth rate and average stained area of the myosin heavy chain. Analysis of PCA and heatmap showed that the morphological parameters could be used to discriminate the differences of passages and lots. Various morphological parameters were analyzed, which revealed that accumulating time-course information regarding morphological heterogeneity in cell populations is crucial to predicting the potencies. Based on the 36 and 60 h morphological profiles, the best proliferation potency prediction model (R2 = 0.95, RMSE = 1.1) and differentiation potency prediction model (R2 = 0.74, RMSE = 1.2) were explored. Correlation analysis demonstrated that morphological parameters selected in models are related to the quality of porcine muscle stem cells.

Effects of proanthocyanidins and dialdehyde chitosan on the proliferation and differentiation of bovine myoblast for cultured meat production

Cultured meat technology intends to manufacture meat by cultivating muscle stem cells in vitro, which is an emerging methodology in meat production. However, the insufficient stemness of bovine myoblasts cultivated in vitro declined the ability of cell expansion and myogenic differentiation, which limited the production of cultured meat. Therefore, in this study, we introduced proanthocyanidins (PC, natural polyphenolic compounds) and dialdehyde chitosan (DAC, natural polysaccharides) to explore the effects of proliferation and differentiation of bovine myoblasts in vitro. The experiment results revealed that PC and DAC promoted cell proliferation by improving the transition from G1 to the S phase as well as cell division in G2. Meanwhile, the myogenic differentiation of cells was further boosted by the combined PC and DAC up-regulation of MYH3 expression. Moreover, the study revealed the synergistic effect of PC and DAC on enhancing the structural stability of collagen, and bovine myoblasts demonstrated excellent growth and dispersion ability on collagen scaffolds. It is concluded that both PC and DAC promote the proliferation and differentiation of bovine myoblasts, contributing to the development of cultured meat production systems.

The Effect of Long-Term Passage on Porcine SMCs' Function and the Improvement of TGF-β1 on Porcine SMCs' Secretory Function in Late Passage

Cultured meat is one of the meat substitutes produced through tissue engineering and other technologies. Large-scale cell culture is the key for cultured meat products to enter the market. Therefore, this study is aimed to explore the effect of long-term passage in vitro on smooth muscle cells (SMCs) and the effect of transforming growth factor-β1 (TGF-β1) on SMCs in the late passage. Multiple passages lead to the decline of the proliferation rate of SMCs in the proliferation stage and the differentiation ability in the differentiation stage. Transcriptome results showed that the ECM pathway and aging-related signaling pathways were significantly up-regulated in the late passage period. TGF-β1 did not promote SMCs of late passage proliferation at the proliferation stage but promoted the gene and protein expression of collagen as the main protein of the extracellular matrix proteins at the differentiation stage. In addition, proteomic analysis revealed that TGF-β1 promoted the expression of cell adhesion molecules which activate the Hippo signaling pathway and the HIF-1 signaling pathway and further promoted the production of collagen-containing extracellular matrix proteins. This could provide ideas for large-scale production of cultured meat products using SMCs.

Visualizing the distribution of flavonoids in litchi (Litchi chinenis) seeds through matrix-assisted laser desorption/ionization mass spectrometry imaging

Flavonoids are one of the most important bioactive components in litchi (Litchi chinensis Sonn.) seeds and have broad-spectrum antiviral and antitumor activities. Litchi seeds have been shown to inhibit the proliferation of cancer cells and induce apoptosis, particularly effective against breast and liver cancers. Elucidating the distribution of flavonoids is important for understanding their physiological and biochemical functions and facilitating their efficient extraction and utilization. However, the spatial distribution patterns and expression states of flavonoids in litchi seeds remain unclear. Herein, matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) was used for in situ detection and imaging of the distribution of flavonoids in litchi seed tissue sections for the first time. Fifteen flavonoid ion signals, including liquiritigenin, apigenin, naringenin, luteolin, dihydrokaempferol, daidzein, quercetin, taxifolin, kaempferol, isorhamnetin, myricetin, catechin, quercetin 3-β-d-glucoside, baicalin, and rutin, were successfully detected and imaged in situ through MALDI-MSI in the positive ion mode using 2-mercaptobenzothiazole as a matrix. The results clearly showed the heterogeneous distribution of flavonoids, indicating the potential of litchi seeds for flavonoid compound extraction. MALDI-MS-based multi-imaging enhanced the visualization of spatial distribution and expression states of flavonoids. Thus, apart from improving our understanding of the spatial distribution of flavonoids in litchi seeds, our findings also facilitate the development of MALDI-MSI-based metabolomics as a novel effective molecular imaging tool for evaluating the spatial distribution of endogenous compounds.

Naringenin Promotes Myotube Formation and Maturation for Cultured Meat Production

Cultured meat is an emerging technology for manufacturing meat through cell culture rather than animal rearing. Under most existing culture systems, the content and maturity of in vitro generated myotubes are insufficient, limiting the application and public acceptance of cultured meat. Here we demonstrated that a natural compound, naringenin (NAR), promoted myogenic differentiation of porcine satellite cells (PSCs) in vitro and increased the content and maturity of generated myotubes, especially for PSCs that had undergone extensive expansion. Mechanistically, NAR upregulated the IGF-1/AKT/mTOR anabolic pathway during the myogenesis of PSCs by activating the estrogen receptor β. Moreover, PSCs were mixed with hydrogels and cultured in a mold with parallel micro-channels to manufacture cultured pork samples. More mature myosin was detected, and obvious sarcomere was observed when the differentiation medium was supplemented with NAR. Taken together, these findings suggested that NAR induced the differentiation of PSCs and generation of mature myotubes through upregulation of the IGF-1 signaling, contributing to the development of efficient and innovative cultured meat production systems.