The inhibitory impacts of Lactobacillus rhamnosus GG-derived extracellular vesicles on the growth of hepatic cancer cells

Biochemical and functional properties of vesicles from planktonic and biofilm phenotypes of Limosilactobacillus reuteri DSM 17938

Limosilactobacillus reuteri DSM 17938 is among the world's most studied probiotic strains and has been shown to provide several health benefits for the host. We have previously shown that the cell-free supernatant of L. reuteri DSM 17938 possesses antimicrobial activity and contains several bioactive compounds. Furthermore, the strain was shown to be a biofilm producer that releases both planktonic and biofilm Membrane Vesicles (MVs). In this study, membrane vesicles isolated from planktonic (pMVs) and biofilm (bMVs) phenotypes were comparatively investigated for their toxicity, ability to kill cancer as well as non-cancer cell lines and modulate phagocytosis in murine macrophages. Neither pMVs nor bMVs showed any in vivo toxicity in a Galleria mellonella model, and weakly affected cancer and noncancerous cell viability after both short- and long-term treatments. However, they were able to affect phagocytosis in lipopolysaccharide challenged RAW 264.7 macrophages, suggesting possible immunomodulatory properties. NMR-based metabolomic analysis of pMVs and bMVs identified and quantified engulfed compounds, mainly organic acids and amino acids, with lactate being the most abundant molecule in both vesicle types. bMVs contained higher concentrations of all measured metabolites compared to pMVs. Proteomic analysis of pMVs and bMVs described equivalent protein cargos, emphasizing quantitative compositional differences that presumably reflect the physiological state of each parent bacterial phenotype. Through the assignment of molecules possibly acting as mediators of immune/inflammatory responses in the host and/or modulating known beneficial effects of L. reuteri, important signaling functions of these vesicles were suggested. Finally, storage stability of MVs up to four weeks was established.

The biological activity and potential of probiotics-derived extracellular vesicles as postbiotics in modulating microbiota-host communication

Probiotics such as Lactobacillus and Bifidobacterium spp. have been shown to be critical for maintaining host homeostasis. In recent years, key compounds of postbiotics derived from probiotic metabolism and cellular secretion have been identified for their role in maintaining organ immunity and regulating intestinal inflammation. In particular, probiotic-derived extracellular vesicles (PEVs) can act as postbiotics, maintaining almost the same functional activity as probiotics. They also have strong biocompatibility and loading capacity to carry exogenous or parental active molecules to reach distal organs to play their roles. This provides a new direction for understanding the intrinsic microbiota-host communication mechanism. However, most current studies on PEVs are limited to their functional effects/benefits, and their specific physicochemical properties, composition, intrinsic mechanisms for maintaining host homeostasis, and possible threats remain to be explored. Here, we review and summarize the unique physicochemical properties of PEVs and their bioactivities and mechanisms in mediating microbiota-host communication, and elucidate the limitations of the current research on PEVs and their potential application as postbiotics.

Biogenesis mechanisms, regulatory strategies, and applications of bacterial extracellular vesicles

Bacterial extracellular vesicles (EVs) are produced by both Gram-negative and Gram-positive bacteria. These EVs are composed of lipid bilayers and various components derived from parent bacteria, including proteins, lipids, and nucleic acids. Previous studies have indicated the significant role of bacterial EVs in interactions between bacteria and between bacteria and hosts. Moreover, bacterial EVs are emerging as promising delivery vectors capable of transporting drug molecules over long distances to tissues. Therefore, understanding the biogenesis of bacterial EVs and how to regulate their production holds great importance for expanding their applications. In this review, we provide an overview of bacterial EVs, especially focusing on the distinct mechanisms of EVs biogenesis and the regulation of EVs production in both Gram-negative and Gram-positive bacteria. Additionally, we discuss various methods for cargos loading into bacteria EVs, as well as their diverse applications in vaccines, cancer therapy, and drug delivery. We anticipate that this review will advance the field of bacterial EVs, contributing to both the enhancement of existing applications and the emergence of novel applications.

Effect of probiotic extracellular vesicles and their applications on health and disease

Probiotics have been established to exert a positive impact on the treatment of various diseases. Indeed, these active microorganisms have garnered significant attention in recent years for their potential to prevent and treat illnesses. Their beneficial effects have been hypothesized to be linked to their released extracellular vesicles. These nanoscale structures, secreted during the growth and metabolism of probiotics, possess favorable biocompatibility and targeting properties, thereby promoting intercellular material transport and signaling. This article aimed to review the bioactive components and functions of these probiotics vesicles, highlighting their role in the treatment of various diseases and discussing their potential future applications. By exploring the mechanisms of probiotic extracellular vesicles in disease development, this review aimed to provide a theoretical reference for further research on their therapeutic potential. © 2025 Society of Chemical Industry.

Lactiplantibacillus plantarum -derived extracellular vesicles alleviate acute lung injury by inhibiting ferroptosis of macrophages

Despite considerable advancements in understanding the mechanisms of ALI, the therapeutic options available in clinical practice remain predominantly supportive, highlighting the urgent need for innovative treatments. In this study, we investigated the potential protective benefits of extracellular vehicles from the probiotic strain Lactiplantibacillus plantarum (LpEVs) in ALI mouse model. We revealed that LpEVs administration attenuated LPS-induced ALI, as evidenced by reduced lung pathology, decreased inflammatory markers, and mitigated ferroptosis. In vitro experiments demonstrated that LpEVs restrained ferroptosis and promoted a shift towards an anti-inflammatory macrophage phenotype. Moreover, LpEVs increased the expression of NRF2, resulting in the promotion of HO1 and strengthening anti-ferroptotic System Xc-/GPX4 axis. Our analysis revealed that LpEVs alleviated ALI through the suppression of macrophages ferroptosis by delivering cbn-let-7 targeting ferroptosis-related gene Acsl4. These findings propose LpEVs as a promising therapeutic approach for preventing and treating ALI, highlighting the potential of leveraging probiotic-derived biomolecules to develop novel therapeutic strategies.

Probiotic Lactobacillus-Derived Extracellular Vesicles: Insights Into Disease Prevention and Management

Bacterial extracellular vesicles (BEVs) have emerged as versatile and promising tools for therapeutic interventions across a spectrum of medical applications. Among these, Lactobacillus-derived extracellular vesicles (LDEVs) have garnered significant attention due to their diverse physiological functions and applications in health advancement. These LDEVs modulate host cell signaling pathways through the delivery of bioactive molecules, including nucleic acids and proteins. The immunomodulatory properties of LDEVs are important, as they have been shown to regulate the balance between pro-inflammatory and anti-inflammatory responses in various diseases. These LDEVs play a crucial role in maintaining gut homeostasis by modulating the composition and function of the gut microbiota, which has implications for health conditions, including inflammatory bowel diseases, metabolic disorders, and neurological disorders. Furthermore, LDEVs hold potential to deliver therapeutic payloads to specific tissues or organs. Engineered LDEVs can be loaded with therapeutic agents such as antimicrobial peptides or nucleic acid-based therapies to treat various diseases. By leveraging the unique properties of LDEVs, researchers can develop innovative strategies for disease prevention, treatment, and overall well-being. Thus, this review aims to provide a comprehensive overview of the therapeutic benefits of LDEVs and their implications for promoting overall well-being.

Unlocking the power of probiotics, postbiotics: targeting apoptosis for the treatment and prevention of digestive diseases

Digestive diseases are becoming an increasingly serious health burden, creating an urgent need to develop more effective treatment strategies. Probiotics and postbiotics have been extensively studied for their potential to prevent and treat digestive diseases. Growing evidence suggests that programmed cell death, especially apoptosis, is a critical mechanism influencing the molecular and biological aspects of digestive diseases, contributing to disease progression. Understanding the mechanisms and signaling pathways by which probiotics and postbiotics regulate apoptosis could reveal new therapeutic targets for treating digestive diseases. This review focuses on the beneficial effects of probiotics and postbiotics in regulating apoptosis across a range of liver diseases, including non-alcoholic fatty liver disease, liver injury, cirrhosis, and liver cancer. It also explores their effects on gastrointestinal diseases, such as colorectal cancer, colitis, gastrointestinal injury, and infectious diarrhea. Furthermore, some probiotics help balance the gut microbiota, enhance intestinal barrier function, and regulate the immune system, all of which are closely associated with apoptosis. Moreover, emerging technologies, such as encapsulation methods, have been developed to stabilize probiotics, primarily based on experimental findings from rodent and human studies.

Anticancer activity of Weizmannia coagulans MZY531on H22 tumor-bearing mice by regulating inflammation, autophagy-dependent apoptosis, and gut microbiota

Increasing studies have shown that the efficacy of Weizmannia coagulans in treating various cancers. We recently identified W. coagulans MZY531 with potent cell anti-proliferation and exhibiting apoptosis induction activities against the mouse H22 hepatocellular carcinoma cell line.However, the anti-cancer effect of W. coagulans MZY531 against liver cancer in vivo has not been verified. The objective of this study was to assess the anti-hepatoma effect of W. coagulans MZY531 on H22 tumor-bearing mice and the underlying mechanism. The results demonstrated that W. coagulans MZY531 reduced the weight and size of the tumor in comparison to the model group. The levels of serum pro-inflammatory cytokines, including IL-1β, IL-6, IL-2 and TNF-α were suppressed by W. coagulans MZY531 administration. Immunofluorescence and TUNEL analyses demonstrated that W. coagulans MZY531 significantly increased the number of cleaved caspase-3 cells and induced apoptosis in tumor tissues. Importantly, W. coagulans MZY531 activated the AMPK/mTOR autophagy-dependent apoptosis pathway, and regulated the TLR4/MyD88/TRAF-6/NF-κB and JAK2/STAT3 inflammatory signaling pathways through mechanisms. Additionally, Fecal analysis demonstrated the capacity of W. coagulans MZY531 to remodel the gut microbiota of hepatocellular carcinoma-infected mice. Collectively, this experimental finding suggested that W. coagulans MZY531 exhibited prominent anticancer activities in vivo at least partly via reducing inflammation, inducing autophagy-dependent apoptosis, and regulating gut microbiota in H22 tumor-bearing mice.

Lactobacillus extracellular vesicles alleviate alcohol-induced liver injury in mice by regulating gut microbiota and activating the Nrf-2 signaling pathway

Lactobacillus derived extracellular vesicles (LAB-EVs) are nanosized particles secreted from Lactobacillus during fermentation, and therefore exist universally in fermented foods such as yogurt, pickles, and fermented beverages. In this study, three LAB-EVs were prepared using a simple scalable method, and then their structures, compositions, and biosafety properties were characterized. The protective properties and potential mechanisms of action of the LAB-EVs against alcoholic liver disease were studied. All three LAB-EVs alleviated alcohol-induced liver injury. It was shown by reduction of liver index, histological damage, liver function impairment, inflammation, and liver oxidative status. The results showed that three LAB-EVs positively promoted the diversity of intestinal flora in mice. Additionally, the relative hepatic protein level of Nrf-2, HO-1, and CYP2E1 was also regulated by LAB-EVs. In summary, these facts suggest that the three LAB-EVs can alleviate alcohol-induced liver damage, by positively modulating the intestinal flora and activation of the Nrf-2 signaling pathway. These results may facilitate the understanding of the composition and function of Lactobacillus fermented food and also the development of Lactobacillus fermented functional food.

Anti-inflammatory Effects of Membrane Vesicles from Eubacterium rectale via the NLRP3 Signal Pathway

Eubacterium rectale (E. rectale) has the ability to attenuate systemic and intestinal inflammation. Its naturally secreted membrane vesicles (MVs) likely play a crucial role in this process. The objective of this study is to investigate the anti-inflammatory effects of E. rectale and its membrane vesicles (MVs). An inflammation model was established by inducing an inflammatory response in Raw 264.7 cells using lipopolysaccharide (LPS). Subsequently, the cells were pre-treated with E. rectale and its MVs, and the expression levels of IL-1β, IL-6, TNF-α, and IL-10 in the cells were then detected using RT-qPCR. ELISA was used to measure the secretion levels of IL-1β, while western blot analysis was employed to assess the expression of key proteins in the IL-1β pathway, specifically ASC, Caspase 1, and NLRP3. The results revealed that both E. rectale and its MVs significantly reduced the expression of the inflammatory cytokines IL-1β and TNF-α in Raw 264.7 cells, which were induced by LPS. Additionally, they markedly upregulated the expression of the anti-inflammatory cytokine IL-10 and suppressed IL-1β expression via the NLRP3-Caspase 1-ASC signaling pathway. These findings suggest that E. rectale, through its membrane vesicles, can attenuate LPS-induced NLRP3 inflammasome activation, thereby mitigating the inflammatory response in Raw 264.7 cells.

Extracellular vesicles of Lactiplantibacillus plantarum PCM 2675 and Lacticaseibacillus rhamnosus PCM 489: an introductory characteristic

Aim: Extracellular vesicles (EVs) are involved in intercellular and interkingdom communication in the complex communities that constitute the niche-specific microbiome of the colonized host. Therefore, studying the structure and content of EVs produced by resident bacteria is crucial to understanding their functionality and impact on the host and other microorganisms. Methods: Bacterial EVs were isolated by differential centrifugation, their size and concentration were measured by transmission electron microscopy and nanoparticle tracking analysis, and the cargo proteins were identified by liquid chromatography coupled to tandem mass spectrometry. The cytotoxicity of bacterial EVs was tested using the human epithelial cell line A549 and an in vivo model of Galleria mellonella larvae. Results: The isolation and preliminary characteristics of EVs from two strains of lactic acid bacteria - Lactiplantibacillus plantarum PCM 2675 and Lacticaseibacillus rhamnosus PCM 489 - were presented, confirming the production of vesicular structures with sizes in the range of 50-170 nm for L. plantarum and 80-250 nm for L. rhamnosus. In addition, various proteins were identified within EVs cargo, with distinct locations of origin, including membrane, cytoplasmic and extracellular proteins, and with diverse functions, including enzymes with confirmed proteolytic activity. Furthermore, bacterial EVs did not show statistically significant cytotoxicity to the host under the tested conditions. Conclusions: A better understanding of the composition and functionality of bacterial EVs may contribute to their future effective use in supporting human health.

Utilization of Probiotic-Derived Extracellular Vesicles as Postbiotics and Their Role in Mental Health Therapeutics

As consumers become more interested in healthier lifestyles, the global functional food market is expanding. Probiotics have gained attention because of their numerous health benefits to the host and may even treat various pathological conditions. Probiotics interact with host cells, and particularly, probiotics-derived extracellular vesicles (PEVs) are key factors in the health benefits of probiotics. Additionally, extracellular vesicles are nano-scaled lipid-bilayer particles that carry various biological molecules, indicating potential as new postbiotics that can provide the same health benefits as probiotics while complementing the side effects associated with probiotics. The importance of mental health care is becoming increasingly prominent considering societal conditions, such as the recent aging population and the coronavirus disease 2019 pandemic. However, the response to mental health issues among modern individuals is insufficient, and there is a need for the development of new personalized treatments to overcome the limitations of current mental health therapies. PEVs have various physiological functions, including mediating cellular communication in the central nervous system, which indicates associations among mental disorders. Therefore, we focused on the beneficial effects of PEVs on the brain and mental health. Recent research has shown that PEVs can adjust the expression of brain-derived neurotrophic factors in vitro and in vivo, demonstrating antidepressant and cognitive function improvement effects. This suggests that PEVs have potential as therapeutic agents for improving mental health and treating brain disorders. Based on this, we review these findings and present the beneficial effects of PEVs on mental health and the challenges that need to be addressed.

The emerging role of bacterial extracellular vesicles in human cancers

Bacterial extracellular vesicles (BEVs) have emerged as pivotal mediators between bacteria and host. In addition to being crucial players in host homeostasis, they have recently been implicated in disease pathologies such as cancer. Hence, the study of BEVs represents an intriguing and rapidly evolving field with substantial translational potential. In this review, we briefly introduce the fundamentals of BEV characteristics, cargo and biogenesis. We emphatically summarize the current relationship between BEVs across various cancer types, illustrating their role in tumorigenesis, treatment responses and patient survival. We further discuss the inherent advantages of BEVs, such as stability, abundance and specific cargo profiles, that make them attractive candidates for non-invasive diagnostic and prognostic approaches. The review also explores the potential of BEVs as a strategy for cancer therapy, considering their ability to deliver therapeutic agents, modulate the tumour microenvironment (TME) and elicit immunomodulatory responses. Understanding the clinical significance of BEVs may lead to the development of better-targeted and personalized treatment strategies. This comprehensive review evaluates the current progress surrounding BEVs and poses questions to encourage further research in this emerging field to harness the benefits of BEVs for their full potential in clinical applications against cancer.

Role of probiotic extracellular vesicles in inter-kingdom communication and current technical limitations in advancing their therapeutic utility

Diverse functions of probiotic extracellular vesicles (EVs) have been extensively studied over the past decade, proposing their role in inter-kingdom communication. Studies have explored their therapeutic role in pathophysiological processes ranging from cancer, immunoregulation, and ulcerative colitis to stress-induced depression. These studies have highlighted the significant and novel potential of probiotic EVs for therapeutic applications, offering immense promise in addressing several unmet clinical needs. Additionally, probiotic EVs are being explored as vehicles for targeted delivery approaches. However, the realization of clinical utility of probiotic EVs is hindered by several knowledge gaps, pitfalls, limitations, and challenges, which impede their wider acceptance by the scientific community. Among these, limited knowledge of EV biogenesis, markers and regulators in bacteria, variations in cargo due to culture conditions or EV isolation method, and lack of proper understanding of gut uptake and demonstration of in vivo effect are some important issues. This review aims to summarize the diverse roles of probiotic EVs in health and disease conditions. More importantly, it discusses the significant knowledge gaps and limitations that stand in the way of the therapeutic utility of probiotic EVs. Furthermore, the importance of addressing these gaps and limitations with technical advances such as rigorous omics has been discussed.

Probiotics-role in alleviating the impact of alcohol liver disease and alcohol deaddiction: a systematic review

Background

There are few efficient treatment options for alcohol addiction, which continues to be a serious public health concern. The possible contribution of gut microbiota to the onset and progression of alcohol addiction has been brought to light by recent studies. Probiotics have become a cutting-edge intervention in the treatment of alcohol consumption disorder because of its favorable effects on gut health. The purpose of this systematic review is to assess the body of research on the advantages of probiotics in treating alcoholism and associated neuroinflammatory conditions.

Methods

To find pertinent research published from January 2012 to 2023, a thorough search of electronic databases, including PubMed, Scopus, Google Scholar and Web of Science, was carried out. Included were studies looking at how probiotics affect neuroinflammation, gut- brain axis regulation, alcohol addiction, and related behaviors.

Findings

Several investigations have shown how beneficial probiotics are in reducing systemic inflammation and alcoholic liver disease (ALD). Probiotic treatments successfully corrected the imbalance of microbiota, decreased intestinal permeability, and stopped the passage of bacterial constituents such lipopolysaccharides (LPS) into the bloodstream. Additionally, probiotics helped to regulate neurotransmitter pathways, especially those connected to GABA, glutamate, and dopamine, which are intimately linked to behaviors related to addiction. Furthermore, it was shown that probiotics altered the expression of neurotransmitter signaling and dopamine receptors.

Conclusion

There is strong evidence from this systematic study that probiotics have potential advantages in treating alcohol addiction. The potential of probiotic therapies is demonstrated by the way they modulate important neurotransmitter pathways implicated in addiction, decrease neuroinflammation, and restore the balance of gut flora. To fully investigate the therapeutic potential of probiotics in treating alcohol addiction and enhancing the general wellbeing of those afflicted by this condition, more research is necessary.

Effects of bacterial extracellular vesicles derived from oral and gastrointestinal pathogens on systemic diseases

Oral microbiota and gastrointestinal microbiota, the two largest microbiomes in the human body, are closely correlated and frequently interact through the oral-gut axis. Recent research has focused on the roles of these microbiomes in human health and diseases. Under normal conditions, probiotics and commensal bacteria can positively impact health. However, altered physiological states may induce dysbiosis, increasing the risk of pathogen colonization. Studies suggest that oral and gastrointestinal pathogens contribute not only to localized diseases at their respective colonized sites but also to the progression of systemic diseases. However, the mechanisms by which bacteria at these local sites are involved in systemic diseases remain elusive. In response to this gap, the focus has shifted to bacterial extracellular vesicles (BEVs), which act as mediators of communication between the microbiota and the host. Numerous studies have reported the targeted delivery of bacterial pathogenic substances from the oral cavity and the gastrointestinal tract to distant organs via BEVs. These pathogenic components subsequently elicit specific cellular responses in target organs, thereby mediating the progression of systemic diseases. This review aims to elucidate the extensive microbial communication via the oral-gut axis, summarize the types and biogenesis mechanisms of BEVs, and highlight the translocation pathways of oral and gastrointestinal BEVs in vivo, as well as the impacts of pathogens-derived BEVs on systemic diseases.

Growth phase matters: Boosting immunity via Lacticasebacillus-derived membrane vesicles and their interactions with TLR2 pathways

Lipid bi-layered particles known as membrane vesicles (MVs), produced by Gram-positive bacteria are a communication tool throughout the entire bacterial growth. However, the MVs characteristics may vary across all stages of maternal culture growth, leading to inconsistencies in MVs research. This, in turn, hinders their employment as nanocarriers, vaccines and other medical applications. In this study, we aimed to comprehensively characterize MVs derived from Lacticaseibacillus rhamnosus CCM7091 isolated at different growth stages: early exponential (6 h, MV6), late exponential (12 h, MV12) and late stationary phase (48 h, MV48). We observed significant differences in protein content between MV6 and MV48 (data are available via ProteomeXchange with identifier PXD041580), likely contributing to their different immunomodulatory capacities. In vitro analysis demonstrated that MV48 uptake rate by epithelial Caco-2 cells is significantly higher and they stimulate an immune response in murine macrophages RAW 264.7 (elevated production of TNFα, IL-6, IL-10, NO). This correlated with increased expression of lipoteichoic acid (LTA) and enhanced TLR2 signalling in MV48, suggesting that LTA contributes to the immunomodulation. In conclusion, we showed that Lacticaseibacillus rhamnosus CCM7091-derived MVs from the late stationary phase boost the immune response the most effectively, which pre-destines them for therapeutical application as nanocarriers.

Extracellular vesicles and cancer stem cells: a deadly duo in tumor progression

The global incidence of cancer is increasing, with estimates suggesting that there will be 26 million new cases and 17 million deaths per year by 2030. Cancer stem cells (CSCs) and extracellular vesicles (EVs) are key to the resistance and advancement of cancer. They play a crucial role in tumor dynamics and resistance to therapy. CSCs, initially discovered in acute myeloid leukemia, are well-known for their involvement in tumor initiation, progression, and relapse, mostly because of their distinct characteristics, such as resistance to drugs and the ability to self-renew. EVs, which include exosomes, microvesicles, and apoptotic bodies, play a vital role in facilitating communication between cells within the tumor microenvironment (TME). They have a significant impact on cellular behaviors and contribute to genetic and epigenetic changes. This paper analyzes the mutually beneficial association between CSCs and EVs, emphasizing their role in promoting tumor spread and developing resistance mechanisms. This review aims to investigate the interaction between these entities in order to discover new approaches for attacking the complex machinery of cancer cells. It highlights the significance of CSCs and EVs as crucial targets in the advancement of novel cancer treatments, which helps stimulate additional research, promote progress in ideas for cancer treatment, and provide renewed optimism in the effort to reduce the burden of cancer.

Host innate immune systems gather intel on invading microbes via pathogen-derived extracellular vesicles

Extracellular vesicles (EVs) are membrane-bound vesicles released into the extracellular milieu from various cell types including host cells and pathogens that infect them. As carriers of nucleic acids, proteins, lipids, metabolites, and virulence factors, EVs act as delivery vehicles for intercellular communication and quorum sensing. Innate immune cells have the capacity to intercept, internalize, and interpret 'messages' contained within these EVs. This review categorizes the ability of EVs secreted by bacterial, parasitic, and fungal pathogens to trigger both pro- and anti-inflammatory innate immune responses in the host. Understanding molecular pathways and inflammatory responses activated in innate immune cells upon pathogen-derived EV stimulation is critical to gain insight into potential therapeutics and combat these infectious diseases.

Unveiling clinical applications of bacterial extracellular vesicles as natural nanomaterials in disease diagnosis and therapeutics

Bacterial extracellular vesicles (BEVs) are naturally occurring bioactive membrane-bound nanoparticles released by both gram-negative and gram-positive bacterial species, exhibiting a multifaceted role in mediating host-microbe interactions across various physiological conditions. Increasing evidence supports BEVs as essential mediators of cell-to-cell communicaiton, influencing bacterial pathogenicity, disease mechanisms, and modulating the host immune response. However, the extent to which these BEV-mediated actions can be leveraged to predict disease onset, guide treatment strategies, and determine clinical outcomes remains uncertain, particularly in terms of their clinical translation potentials. This review briefly describes BEV biogenesis and their internalisation by recipient cells and summarises methods for isolation and characterization, essential for understanding their composition and cargo. Further, it discusses the potential of biofluid-associated BEVs as biomarkers for various diseases, spanning both cancer and non-cancerous conditions. Following this, we outline the ongoing human clinical trials of using BEVs for vaccine development. In addition to disease diagnostics, this review explores the emerging research of using natural or engineered BEVs as smart nanomaterials for applications in anti-cancer therapy and bone regeneration. This discussion extends to key factors for unlocking the clinical potential of BEVs, such as standardization of BEV isolation and characterisation, as well as other hurdles in translating these findings to the clinical setting. We propose that addressing these hurdles through collaborative research efforts and well-designed clinical trials holds the key to fully harnessing the clinical potential of BEVs. As this field advances, this review suggests that BEV-based nanomedicine has the potential to revolutionize disease management, paving the way for innovative diagnosis, therapeutics, and personalized medicine approaches. STATEMENT OF SIGNIFICANCE: Extracellular vesicles (EVs) from both host cells and bacteria serve as multifunctional biomaterials and are emerging in the fields of biomedicine, bioengineering, and biomaterials. However, the majority of current studies focus on host-derived EVs, leaving a gap in comprehensive research on bacteria-derived EVs (BEVs). Although BEVs offer an attractive option as nanomaterials for drug delivery systems, their unique nanostructure and easy-to-modify functions make them a potential method for disease diagnosis and treatment as well as vaccine development. Our work among the pioneering studies investigating the potential of BEVs as natural nanobiomaterials plays a crucial role in both understanding the development of diseases and therapeutic interventions.

Harnessing Bacterial Extracellular Vesicle Immune Effects for Cancer Therapy

There are a growing number of studies linking the composition of the human microbiome to disease states and treatment responses, especially in the context of cancer. This has raised significant interest in developing microbes and microbial products as cancer immunotherapeutics that mimic or recapitulate the beneficial effects of host-microbe interactions. Bacterial extracellular vesicles (bEVs) are nano-sized, membrane-bound particles secreted by essentially all bacteria species and contain a diverse bioactive cargo of the producing cell. They have a fundamental role in facilitating interactions among cells of the same species, different microbial species, and even with multicellular host organisms in the context of colonization (microbiome) and infection. The interaction of bEVs with the immune system has been studied extensively in the context of infection and suggests that bEV effects depend largely on the producing species. They thus provide functional diversity, while also being nonreplicative, having inherent cell-targeting qualities, and potentially overcoming natural barriers. These characteristics make them highly appealing for development as cancer immunotherapeutics. Both natively secreted and engineered bEVs are now being investigated for their application as immunotherapeutics, vaccines, drug delivery vehicles, and combinations of the above, with promising early results. This suggests that both the intrinsic immunomodulatory properties of bEVs and their ability to be modified could be harnessed for the development of next-generation microbe-inspired therapies. Nonetheless, there remain major outstanding questions regarding how the observed preclinical effectiveness will translate from murine models to primates, and humans in particular. Moreover, research into the pharmacology, toxicology, and mass manufacturing of this potential novel therapeutic platform is still at early stages. In this review, we highlight the breadth of bEV interactions with host cells, focusing on immunologic effects as the main mechanism of action of bEVs currently in preclinical development. We review the literature on ongoing efforts to develop natively secreted and engineered bEVs from a variety of bacterial species for cancer therapy and finally discuss efforts to overcome outstanding challenges that remain for clinical translation.

A promising area of research in medicine: recent advances in properties and applications of Lactobacillus-derived exosomes

Lactobacillus-derived exosomes, small extracellular vesicles released by bacteria, have emerged as a promising area of research in recent years. These exosomes possess a unique structural and functional diversity that allows them to regulate the immune response and promote gut health. The isolation and purification of these exosomes are crucial for their effective use as a therapeutic agent. Several isolation and purification methods have been developed, including differential ultracentrifugation, density gradient centrifugation, and size-exclusion chromatography. Lactobacillus-derived exosomes have been demonstrated to have therapeutic potential in various diseases, such as inflammatory bowel disease, liver disease, and neurological disorders. Moreover, they have been shown to serve as effective carriers for drug delivery. Genetic engineering of these exosomes has also shown promise in enhancing their therapeutic potential. Overall, Lactobacillus-derived exosomes represent a promising area of research for the development of novel therapeutics for immunomodulation, gut health, and drug delivery.

Molecular Mechanisms of Lacticaseibacillus rhamnosus, LGG® Probiotic Function

To advance probiotic research, a comprehensive understanding of bacterial interactions with human physiology at the molecular and cellular levels is fundamental. Lacticaseibacillus rhamnosus LGG® is a bacterial strain that has long been recognized for its beneficial effects on human health. Probiotic effector molecules derived from LGG®, including secreted proteins, surface-anchored proteins, polysaccharides, and lipoteichoic acids, which interact with host physiological processes have been identified. In vitro and animal studies have revealed that specific LGG® effector molecules stimulate epithelial cell survival, preserve intestinal barrier integrity, reduce oxidative stress, mitigate excessive mucosal inflammation, enhance IgA secretion, and provide long-term protection through epigenetic imprinting. Pili on the cell surface of LGG® promote adhesion to the intestinal mucosa and ensure close contact to host cells. Extracellular vesicles produced by LGG® recapitulate many of these effects through their cargo of effector molecules. Collectively, the effector molecules of LGG® exert a significant influence on both the gut mucosa and immune system, which promotes intestinal homeostasis and immune tolerance.

Interactions of Gram-Positive Bacterial Membrane Vesicles and Hosts: Updates and Future Directions

Extracellular vesicles (EVs) are lipid bilayers derived from cell membranes, released by both eukaryotic cells and bacteria into the extracellular environment. During production, EVs carry proteins, nucleic acids, and various compounds, which are then released. While Gram-positive bacteria were traditionally thought incapable of producing EVs due to their thick peptidoglycan cell walls, recent studies on membrane vesicles (MVs) in Gram-positive bacteria have revealed their significant role in bacterial physiology and disease progression. This review explores the current understanding of MVs in Gram-positive bacteria, including the characterization of their content and functions, as well as their interactions with host and bacterial cells. It offers a fresh perspective to enhance our comprehension of Gram-positive bacterial EVs.

The activation impact of lactobacillus-derived extracellular vesicles on lipopolysaccharide-induced microglial cell

Perioperative neurocognitive dysfunction (PND) emerges as a common postoperative complication among elderly patients. Currently, the mechanism of PND remains unclear, but there exists a tendency to believe that inflammation plays a significant role in PND. Alterations in the abundance of intestinal microbiota can increase the permeability of the intestinal mucosal barrier and incite extraintestinal inflammatory responses. Metabolites from these microbiota can be absorbed by the intestinal mucosa into the bloodstream, exerting influence upon the central nervous system (CNS). Lactobacillus (Lac), serving as an intestinal probiotic bacterium, possesses the capacity to modulate emotional behavior and cognitive functions. Extracellular vesicles (EVs) are recognized as novel therapeutic carriers for targeted delivery to regulate physiology and pathogenesis. While the mechanism governing the primary function of Lac-EVs in the CNS remains uncertain. Therefore, we established an in vitro neuroinflammation model to induce PND and then treated the mice with Lac-EVs to observe the effect of these EVs on neuroinflammation, particularly on microglial (MG) polarization. Our research unveils that Lac-EVs reduced inflammation induced by LPS in microglia and the activation of related proteins, including the mRNA expression of M1 labeled protein (iNOS). Moreover, the mRNA expression of M2-labeled protein (Arg1) increased. In addition, flow cytometry revealed that the ratio of M1/M2 microglia also changed significantly. Therefore, Lac-EVs promoted the differentiation of M2 microglia by inducing the preferential expression of specific markers related to M2 macrophages and inflammation. In terms of inflammatory cytokine expression, Lac-EVs decreased the secretion of proinflammatory cytokines (IL-1β and IL-6) and increased IL-10 production after lipopolysaccharide (LPS) stimulation. Therefore, Lac-EVs induce the activation of M2 microglial cells without inducing cellular harm in vitro, and they demonstrate anti-inflammatory effects against lipopolysaccharide-induced neuroinflammation. This finding suggested that it is an effective anti-inflammatory strategy for alleviating inflammation-driven PNDs.

The inhibition effects of Lentilactobacillus buchneri-derived membrane vesicles on AGS and HT-29 cancer cells by inducing cell apoptosis

In recent years, probiotics and their derivatives have been recognized as important therapeutic agents in the fight against cancer. Therefore, this study aimed to investigate the anticancer effects of membrane vesicles (MVs) from Lentilactobacillus buchneri strain HBUM07105 probiotic isolated from conventional and unprocessed yogurt in Arak province, Iran, against gastric and colon cancer cell lines. The MVs were prepared from the cell-free supernatant (CFS) of L. buchneri and characterized using field-emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) and SPS-PAGE techniques. The anticancer activity of MVs was evaluated using MTT, flow cytometry, qRT-PCR techniques, and a scratch assay. The study investigated the anti-adenocarcinoma effect of MVs isolated from L. buchneri on a human gastric adenocarcinoma cell line (AGS) and a human colorectal adenocarcinoma cell line (HT-29) at 24, 48, and 72-h time intervals. The results demonstrated that all prepared concentrations (12.5, 25, 50, 100, and 200 µg/mL) of MVs reduced the viability of both types of human adenocarcinoma cells after 24, 48, and 72 h of treatment. The analysis of the apoptosis results revealed that the percentage of AGS and HT-29 cancer cells in the early and late stages of apoptosis was significantly higher after 24, 48, and 72 h of treatment compared to the untreated cancer cells. After treating both AGS and HT-29 cells with the MVs, the cells were arrested in the G0/G1 phase. These microvesicles demonstrate apoptotic activity by increasing the expression of pro-apoptotic genes (BAX, CASP3, and CASP9). According to the scratch test, MVs can significantly decrease the migration of HT-29 and AGS cancer cells after 24, 48, and 72 h of incubation compared to the control groups. The MVs of L. buchneri can also be considered a potential option for inhibiting cancer cell activities.

Extracellular vesicles from Lacticaseibacillus paracasei PC-H1 inhibit HIF-1α-mediated glycolysis of colon cancer

Aims: Extracellular vesicles from Lacticaseibacillus paracasei PC-H1 have antiproliferative activity of colon cells, but the effect on glycolytic metabolism of cancer cell remains enigmatic. The authors investigated how Lacticaseibacillus paracasei extracellular vesicles (LpEVs) inhibit the growth of colon cancer cells by affecting tumor metabolism. Materials & methods: HCT116 cells were treated with LpEVs and then differentially expressed genes were analyzed by transcriptome sequencing, the sequencing results were confirmed in vivo and in vitro. Results: LpEVs entered colon cancer cells and inhibited their growth. Transcriptome sequencing revealed differentially expressed genes were related to glycolysis. Lactate production, glucose uptake and lactate dehydrogenase activity were significantly reduced after treatment. LpEVs also reduced HIF-1α, GLUT1 and LDHA expression. Conclusion: LpEVs exert their antiproliferative activity of colon cancer cells by decreasing HIF-1α-mediated glycolysis.

Lactic acid bacteria derived extracellular vesicles: emerging bioactive nanoparticles in modulating host health

Lactic acid bacteria derived extracellular vesicles (LAB-EVs) are nano-sized and carry a variety of biological cargoes. LAB-EVs have proven to be potential mediators of intercellular communication, serving not only the parental bacteria but also the host cell in both physiology and pathology. LAB-EVs are therapeutically beneficial in various diseases through a cell-free strategy. Particularly, EVs secreted from probiotics can exert health-promoting effects on humans. Additionally, the excitement around LAB-EVs has extended to their use as nano-sized drug carriers, since they can traverse biological barriers. Nevertheless, significant challenges in terms of isolation, characterization, and safety must be addressed to ensure the clinical application of LAB-EVs. Therefore, this review emphasizes the isolation and purification methods of LAB-EVs. We also introduce the biogenesis, cargo sorting, and functions of LAB-EVs. The biological regulatory factors of LAB-EVs are summarized and discussed. Special attention is given to the interaction between LAB-EVs and the host, their ability to maintain intestinal homeostasis, and the immunity and inflammation they induce in diverse diseases. Furthermore, we summarize the characterization of LAB-EV cargoes by advanced analytical methods such as proteomics. Finally, we discuss the challenges and opportunities of LAB-EVs as a means of diagnosis and treatment in clinical translation. In conclusion, this review scrutinizes current knowledge and provides guidelines for proposing new perspectives for future research in the field of LAB-EVs.

Modulation of Caco-2 Colon Cancer Cell Viability and CYP2W1 Gene Expression by Hesperidin-treated Lacticaseibacillus rhamnosus GG (LGG) Cell-free Supernatants

BACKGROUND AND OBJECTIVE

Ensuring colon homeostasis is of significant influence on colon cancer and delicate balance is maintained by a healthy human gut microbiota. Probiotics can modulate the diversity of the gut microbiome and prevent colon cancer. Metabolites/byproducts generated by microbial metabolism significantly impact the healthy colonic environment. Hesperidin is a polyphenolic plant compound well known for its anticancer properties. However, low bioavailability of hesperidin after digestion impedes its effectiveness. CYP2W1 is a newly discovered oncofetal gene with an unknown function. CYP2W1 gene expression peaks during embryonic development and is suddenly silenced immediately after birth. Only in the case of some types of cancer, particularly colorectal and hepatocellular carcinomas, this gene is reactivated and its expression is correlated with the severity of the disease. This study aimed to investigate the effects of hesperidin-treated Lacticaseibacillus rhamnosus GG (LGG) cell-free supernatants on CaCo2 colon cancer cell viability and CYP2W1 gene expression.

METHODS

Alamar Blue cell viability assay was used to investigate the cytotoxic effect of cell-free supernatant of LGG grown in the presence of hesperidin on CaCo2 cells. To observe the effect of cell-free supernatants of LGG on the expression of CYP2W1 gene, qRT-PCR was performed.

RESULTS

Five times diluted hesperidin treated cell-free supernatant (CFS) concentration considerably reduced CaCo2 colon cancer cell viability. Furthermore, CYP2W1 gene expression was similarly reduced following CFS treatments and nearly silenced under probiotic bacteria CFS treatment.

CONCLUSION

The CYP2W1 gene expression was strongly reduced by cell-free supernatants derived from LGG culture, with or without hesperidin. This suggests that the suppression may be due to bacterial byproducts rather than hesperidin. Therefore, the CYP2W1 gene in the case of deregulation of these metabolites may cause CYP2W1-related colon cancer cell proliferation.

Human Probiotic Lactobacillus paracasei-Derived Extracellular Vesicles Improve Tumor Necrosis Factor-α-Induced Inflammatory Phenotypes in Human Skin

Lactic acid bacteria (LAB), a probiotic, provide various health benefits. We recently isolated a new Lactobacillus paracasei strain with strong anti-inflammatory effects under lipopolysaccharide-induced conditions and proposed a new mode of action-augmenting the endoplasmic reticulum stress pathway for anti-inflammatory functions in host cells. The beneficial effects of the L. paracasei strains on the skin have been described; however, the effects of L. paracasei-derived extracellular vesicles (LpEVs) on the skin are poorly understood. Herein, we investigated whether LpEVs can improve inflammation-mediated skin phenotypes by determining their effects on primary human skin cells and a three-dimensional (3D) full-thickness human skin equivalent under tumor necrosis factor (TNF)-α-challenged inflammatory conditions. LpEVs were efficiently taken up by the human skin cells and were much less cytotoxic to host cells than bacterial lysates. Furthermore, low LpEV concentrations efficiently restored TNF-α-induced cellular phenotypes, resulting in increased cell proliferation and collagen synthesis, but decreased inflammatory factor levels (matrix metalloproteinase 1, interleukin 6, and interleukin 8) in the human dermal fibroblasts, which was comparable to that of retinoic acid, a representative antiaging compound. The beneficial effects of LpEVs were validated in a 3D full-thickness human skin equivalent model. LpEV treatment remarkably restored the TNF-α-induced epidermal malformation, abnormal proliferation of keratinocytes in the basal layer, and reduction in dermal collagen synthesis. Additionally, LpEVs penetrated and reached the deepest dermal layer within 24 h when overlaid on top of a 3D full-thickness human skin equivalent. Furthermore, they possessed superior antioxidant capacity compared with the human cell-derived EVs. Taken together, the anti-inflammatory probiotic LpEVs can be attractive antiaging and antioxidant substances for improving inflammation-induced skin phenotypes and disorders.

Extracellular nanovesicles produced by Bacillus licheniformis: A potential anticancer agent for breast and lung cancer

Cancer is a major public burden and leading cause of death worldwide; furthermore, it is a significant barrier to increasing life expectancy in most countries of the world. Among various types of cancers, breast and lung cancers lead to significant mortality in both males and females annually. Bacteria-derived products have been explored for their use in cancer therapy. Although bacteria contain significant amounts of anticancer substances, attenuated bacteria may still pose a potential risk for infection owing to the variety of immunomodulatory molecules present in the parental bacteria; therefore, non-cellular bacterial extracellular vesicles (BEVs), which are naturally non-replicating, safer, and are considered to be potential anticancer agents, are preferred for cancer therapy. Gram-positive bacteria actively secrete cytoplasmic membrane vesicles that are spherical and vary between 10 and 400 nm in size. However, no studies have considered cytoplasmic membrane vesicles derived from Bacillus licheniformisin cancer treatment. In this study, we investigated the potential use of B. licheniformis extracellular nanovesicles (BENVs) as therapeutic agents to treat cancer. Purified BENVs from the culture supernatant of B. licheniformis using ultracentrifugation and ExoQuick were characterized using a series of analytical techniques. Human breast cancer cells (MDA-MB-231) and lung cancer cells (A549) were treated with different concentrations of purified BENVs, which inhibited the cell viability and proliferation, and increased cytotoxicity in a dose-dependent manner. To elucidate the mechanism underlying the anticancer activity of BENVs, the oxidative stress markers such as reactive oxygen species (ROS) and glutathione (GSH) levels were measured. The ROS levels were significantly higher in BENV-treated cells, whereas the GSH levels were markedly reduced. Cells treated with BENVs, doxorubicin (DOX), or a combination of BENVs and DOX showed significantly increased expression of p53, p21, caspase-9/3, and Bax, and concomitantly decreased expression of Bcl-2. The combination of BENVs and doxorubicin enhanced mitochondrial dysfunction, DNA damage, and apoptosis. To our knowledge, this is the first study to determine the anticancer properties of BENVs derived from industrially significant probacteria on breast and lung cancer cells.

High performance anion exchange chromatography purification of probiotic bacterial extracellular vesicles enhances purity and anti-inflammatory efficacy

Bacterial extracellular vesicles (BEVs), including outer membrane vesicles, have emerged as a promising new class of vaccines and therapeutics to treat cancer and inflammatory diseases, among other applications. However, clinical translation of BEVs is hindered by a current lack of scalable and efficient purification methods. Here, we address downstream BEV biomanufacturing limitations by developing a method for orthogonal size- and charge-based BEV enrichment using tangential flow filtration (TFF) in tandem with high performance anion exchange chromatography (HPAEC). The data show that size-based separation coisolated protein contaminants, whereas size-based TFF with charged-based HPAEC dramatically improved purity of BEVs produced by probiotic Gram-negative Escherichia coli and Gram-positive lactic acid bacteria (LAB). Escherichia coli BEV purity was quantified using established biochemical markers while improved LAB BEV purity was assessed via observed potentiation of anti-inflammatory bioactivity. Overall, this work establishes orthogonal TFF + HPAEC as a scalable and efficient method for BEV purification that holds promise for future large-scale biomanufacturing of therapeutic BEV products.

Isolation and Characterization of Cow-, Buffalo-, Sheep- and Goat-Milk-Derived Extracellular Vesicles

Milk is a complex biological fluid that has high-quality proteins including growth factors and also contains extracellular vesicles (EVs). EVs are a lipid bilayer containing vesicles that contain proteins, metabolites and nucleic acids. Several studies have proposed that EVs in cow milk can survive the gut and can illicit cross-species communication in the consuming host organism. In this study, we isolated and characterized extracellular vesicles from the raw milk of the four species of the Bovidae family, namely cow, sheep, goat and buffalo, that contribute 99% of the total milk consumed globally. A comparative proteomic analysis of these vesicles was performed to pinpoint their potential functional role in health and disease. Vesicles sourced from buffalo and cow milk were particularly enriched with proteins implicated in modulating the immune system. Furthermore, functional studies were performed to determine the anti-cancer effects of these vesicles. The data obtained revealed that buffalo-milk-derived EVs induced significantly higher cell death in colon cancer cells. Overall, the results from this study highlight the potent immunoregulatory and anti-cancer nature of EVs derived from the milk of Bovidae family members.

An update on our understanding of Gram-positive bacterial membrane vesicles: discovery, functions, and applications

Extracellular vesicles (EVs) are nano-sized particles released from cells into the extracellular environment, and are separated from eukaryotic cells, bacteria, and other organisms with cellular structures. EVs alter cell communication by delivering their contents and performing various functions depending on their cargo and release into certain environments or other cells. The cell walls of Gram-positive bacteria have a thick peptidoglycan layer and were previously thought to be unable to produce EVs. However, recent studies have demonstrated that Gram-positive bacterial EVs are crucial for health and disease. In this review, we have summarized the formation, composition, and characteristics of the contents, resistance to external stress, participation in immune regulation, and other functions of Gram-positive bacterial EVs, as well as their application in clinical diagnosis and treatment, to provide a new perspective to further our understanding of Gram-positive bacterial EVs.

Potential effects of gut microbiota on host cancers: focus on immunity, DNA damage, cellular pathways, and anticancer therapy

The symbiotic bacteria that live in the human gut and the metabolites they produce have long influenced local and systemic physiological and pathological processes of the host. The gut microbiota are increasingly being recognized for its impact on a range of human diseases, including cancer, it may play a key role in the occurrence, progression, treatment, and prognosis of many types of cancer. Understanding the functional role of the gut microbiota in cancer is crucial for the development of the era of personalized medicine. Here, we review recent advances in research and summarize the important associations and clear experimental evidence for the role of the gut microbiota in a variety of human cancers, focus on the application and possible challenges associated with the gut microbiota in antitumor therapy. In conclusion, our research demonstrated the multifaceted mechanisms of gut microbiota affecting human cancer and provides directions and ideas for future clinical research.

Emerging therapeutic role of gut microbial extracellular vesicles in neurological disorders

Extracellular vesicles (EVs) serve as cell-to-cell and inter-organ communicators by conveying proteins and nucleic acids with regulatory functions. Emerging evidence shows that gut microbial-released EVs play a pivotal role in the gut-brain axis, bidirectional communication, and crosstalk between the gut and the brain. Increasing pre-clinical and clinical evidence suggests that gut bacteria-released EVs are capable of eliciting distinct signaling to the brain with the ability to cross the blood-brain barrier, exerting regulatory function on brain cells such as neurons, astrocytes, and microglia, via their abundant and diversified protein and nucleic acid cargo. Conversely, EVs derived from certain species of bacteria, particularly from gut commensals with probiotic properties, have recently been shown to confer distinct therapeutic effects on various neurological disorders. Thus, gut bacterial EVs may be both a cause of and therapy for neuropathological complications. This review marshals the basic, clinical, and translational studies that significantly contributed to our up-to-date knowledge of the therapeutic potential of gut microbial-derived EVs in treating neurological disorders, including strokes, Alzheimer's and Parkinson's disease, and dementia. The review also discusses the newer insights in recent studies focused on developing superior therapeutic microbial EVs via genetic manipulation and/or dietary intervention.

A Review of the Aquatic Environmental Transformations of Engineered Nanomaterials

Once released into the environment, engineered nanomaterials (ENMs) undergo complex interactions and transformations that determine their fate, exposure concentration, form, and likely impact on biota. Transformations are physical, chemical, or biological changes that occur to the ENM or the ENM coating. Over time, these transformations have an impact on their behaviour and properties. The interactions and transformations of ENMs in the environment depend on their pristine physical and chemical characteristics and the environmental or biological compartment into which they are released. The uniqueness of each ENM property or lifecycle results in a great deal of complexity. Even small changes may have a significant impact on their potential transformations. This review outlines the key influences and outcomes of ENM evolution pathways in aquatic environments and provides an assessment of potential environmental transformations, focusing on key chemical, physical, and biological processes. By obtaining a comprehensive understanding of the potential environmental transformations that nanomaterials can undergo, more realistic models of their probable environmental behaviour and potential impact can be developed. This will, in turn, be crucial in supporting regulatory bodies in their efforts to develop environmental policy in the field of nanotechnology.

Deciphering psychobiotics' mechanism of action: bacterial extracellular vesicles in the spotlight

The intake of psychobiotic bacteria appears to be a promising adjunct to neuropsychiatric treatment, and their consumption may even be beneficial for healthy people in terms of mental functioning. The psychobiotics' mechanism of action is largely outlined by the gut-brain axis; however, it is not fully understood. Based on very recent studies, we provide compelling evidence to suggest a novel understanding of this mechanism: bacterial extracellular vesicles appear to mediate many known effects that psychobiotic bacteria exert on the brain. In this mini-review paper, we characterize the extracellular vesicles derived from psychobiotic bacteria to demonstrate that they can be absorbed from the gastrointestinal tract, penetrate to the brain, and carry the intracellular content to exert beneficial multidirectional action. Specifically, by regulating epigenetic factors, extracellular vesicles from psychobiotics appear to enhance expression of neurotrophic molecules, improve serotonergic neurotransmission, and likely supply astrocytes with glycolytic enzymes to favor neuroprotective mechanisms. As a result, some data suggest an antidepressant action of extracellular vesicles that originate even from taxonomically remote psychobiotic bacteria. As such, these extracellular vesicles may be regarded as postbiotics of potentially therapeutic application. The mini-review is enriched with illustrations to better introduce the complex nature of brain signaling mediated by bacterial extracellular vesicles and indicates knowledge gaps that require scientific exploration before further progress is made. In conclusion, bacterial extracellular vesicles appear to represent the missing piece of the puzzle in the mechanism of action of psychobiotics.

Role of Bacterial Extracellular Vesicles in Manipulating Infection

Mammalian-cell-derived extracellular vesicles, such as exosomes, have been a key focal point for investigating host-pathogen interactions and are major facilitators in modulating both bacterial and viral infection. However, in recent years, increasing attention has been given to extracellular vesicles produced by bacteria and the role they play in regulating infection and disease. Extracellular vesicles produced by pathogenic bacteria employ a myriad of strategies to assist in bacterial virulence or divert antibacterial responses away from the parental bacterium to promote infection by and survival of the parental bacterium. Commensal bacteria also produce extracellular vesicles. These vesicles can play a variety of roles during infection, depending on the bacterium, but have been primarily shown to aid the host by stimulating innate immune responses to control infection by both bacteria and viruses. This article will review the activities of bacterial extracellular vesicles known to modulate infection by bacterial and viral pathogens.

High performance anion exchange chromatography purification of probiotic bacterial extracellular vesicles enhances purity and anti-inflammatory efficacy

Bacterial extracellular vesicles (BEVs), including outer membrane vesicles (OMVs), have emerged as a promising new class of vaccines and therapeutics to treat cancer and inflammatory diseases, among other applications. However, clinical translation of BEVs is hindered by a current lack of scalable and efficient purification methods. Here, we address downstream BEV biomanufacturing limitations by developing a method for orthogonal size- and charge-based BEV enrichment using tangential flow filtration (TFF) in tandem with high performance anion exchange chromatography (HPAEC). The data show that size-based separation co-isolated protein contaminants, whereas size-based TFF with charged-based HPAEC dramatically improved purity of BEVs produced by probiotic Gram-negative Escherichia coli and Gram-positive lactic acid bacteria (LAB). E. coli BEV purity was quantified using established biochemical markers while improved LAB BEV purity was assessed via observed potentiation of anti-inflammatory bioactivity. Overall, this work establishes orthogonal TFF + HPAEC as a scalable and efficient method for BEV purification that holds promise for future large-scale biomanufacturing of therapeutic BEV products.

Bacterial Membrane Vesicles as Smart Drug Delivery and Carrier Systems: A New Nanosystems Tool for Current Anticancer and Antimicrobial Therapy

Bacterial membrane vesicles (BMVs) are known to be critical communication tools in several pathophysiological processes between bacteria and host cells. Given this situation, BMVs for transporting and delivering exogenous therapeutic cargoes have been inspiring as promising platforms for developing smart drug delivery systems (SDDSs). In the first section of this review paper, starting with an introduction to pharmaceutical technology and nanotechnology, we delve into the design and classification of SDDSs. We discuss the characteristics of BMVs including their size, shape, charge, effective production and purification techniques, and the different methods used for cargo loading and drug encapsulation. We also shed light on the drug release mechanism, the design of BMVs as smart carriers, and recent remarkable findings on the potential of BMVs for anticancer and antimicrobial therapy. Furthermore, this review covers the safety of BMVs and the challenges that need to be overcome for clinical use. Finally, we discuss the recent advancements and prospects for BMVs as SDDSs and highlight their potential in revolutionizing the fields of nanomedicine and drug delivery. In conclusion, this review paper aims to provide a comprehensive overview of the state-of-the-art field of BMVs as SDDSs, encompassing their design, composition, fabrication, purification, and characterization, as well as the various strategies used for targeted delivery. Considering this information, the aim of this review is to provide researchers in the field with a comprehensive understanding of the current state of BMVs as SDDSs, enabling them to identify critical gaps and formulate new hypotheses to accelerate the progress of the field.

Lactobacillus plantarum Metabolites Elicit Anticancer Effects by Inhibiting Autophagy-Related Responses

Lactobacillus plantarum (L. plantarum) is a probiotic that has emerged as novel therapeutic agents for managing various diseases, such as cancer, atopic dermatitis, inflammatory bowel disease, and infections. In this study, we investigated the potential mechanisms underlying the anticancer effect of the metabolites of L. plantarum. We cultured L. plantarum cells to obtain their metabolites, created several dilutions, and used these solutions to treat human colonic Caco-2 cells. Our results showed a 10% dilution of L. plantarum metabolites decreased cell viability and reduced the expression of autophagy-related proteins. Moreover, we found co-treatment with L. plantarum metabolites and chloroquine, a known autophagy inhibitor, had a synergistic effect on cytotoxicity and downregulation of autophagy-related protein expression. In conclusion, we showed the metabolites from the probiotic, L. plantarum, work synergistically with chloroquine in killing Caco-2 cells and downregulating the expression of autophagy-related proteins, suggesting the involvement of autophagy, rather than apoptosis, in their cytotoxic effect. Hence, this study provides new insights into new therapeutic methods via inhibiting autophagy.

Extracellular Vesicles of Probiotics: Shedding Light on the Biological Activity and Future Applications

For many decades, the proper functioning of the human body has become a leading scientific topic. In the course of numerous experiments, a striking impact of probiotics on the human body has been documented, including maintaining the physiological balance of endogenous microorganisms, regulating the functioning of the immune system, enhancing the digestive properties of the host, and preventing or alleviating the course of many diseases. Recent research, especially from the last decade, shows that this health-benefiting activity of probiotics is largely conditioned by the production of extracellular vesicles. Although the importance of extracellular vesicles in the virulence of many live-threatening pathogens is widely described in the literature, much less is known with respect to the health-promoting effect of extracellular vesicles secreted by non-pathogenic microorganisms, including probiotics. Based on this, in the current review article, we decided to collect the latest literature data on the health-inducing properties of extracellular vesicles secreted by probiotics. The characteristics of probiotics' extracellular vesicles will be extended by the description of their physicochemical properties and the proteome in connection with the biological activities exhibited by these structures.

Anti-inflammatory effects of extracellular vesicles from Morchella on LPS-stimulated RAW264.7 cells via the ROS-mediated p38 MAPK signaling pathway

Morchella is a kind of important edible and medicinal fungi, which is rich in polysaccharides, enzymes, fatty acids, amino acids and other active components. Extracellular vesicles (EVs) have a typical membrane structure, and the vesicles contain some specific lipids, miRNAs and proteins, and their can deliver the contents to different cells to change their functions. The present study investigated whether Morchella produce extracellular vesicles and its anti-inflammatory effect on lipopolysaccharide (LPS)-induced RAW246.7 macrophages. The experimental results showed that Morchella produced extracellular vesicles and significantly reduced the production of nitric oxide (NO) and reactive oxygen species (ROS) in a model of LPS-induced inflammation. In addition, the expression of inflammatory factor-related genes such as inducible nitric oxide synthase (iNOS), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and cyclooxygenase-2 (COX-2) showed dose-dependent inhibition. Morchella extracellular vesicles also can inhibit the inflammatory response induced by LPS by inhibiting the production of ROS and reducing the phosphorylation levels of the p38 MAPK signaling pathway. These results indicate that the Morchella extracellular vesicles can be used as a potential anti-inflammatory substance in the treatment of inflammatory diseases.

Novel Horizons in Postbiotics: Lactobacillaceae Extracellular Vesicles and Their Applications in Health and Disease

Lactobacillus probiotics contained in dietary supplements or functional foods are well-known for their beneficial properties exerted on host health and diverse pathological situations. Their capacity to improve inflammatory bowel disease (IBD) and regulate the immune system is especially remarkable. Although bacteria-host interactions have been thought to occur directly, the key role that extracellular vesicles (EVs) derived from probiotics play on this point is being unveiled. EVs are lipid bilayer-enclosed particles that carry a wide range of cargo compounds and act in different signalling pathways. Notably, these EVs have been recently proposed as a safe alternative to the utilisation of live bacteria since they can avoid the possible risks that probiotics may entail in vulnerable cases such as immunocompromised patients. Therefore, this review aims to give an updated overview of the existing knowledge about EVs from different Lactobacillus strains, their mechanisms and effects in host health and different pathological conditions. All of the information collected suggests that EVs could be considered as potential tools for the development of future novel therapeutic approaches.

Extracellular membrane vesicles from Limosilactobacillus reuteri strengthen the intestinal epithelial integrity, modulate cytokine responses and antagonize activation of TRPV1

Bacterial extracellular membrane vesicles (MV) are potent mediators of microbe-host signals, and they are not only important in host-pathogen interactions but also for the interactions between mutualistic bacteria and their hosts. Studies of MV derived from probiotics could enhance the understanding of these universal signal entities, and here we have studied MV derived from Limosilactobacillus reuteri DSM 17938 and BG-R46. The production of MV increased with cultivation time and after oxygen stress. Mass spectrometry-based proteomics analyses revealed that the MV carried a large number of bacterial cell surface proteins, several predicted to be involved in host-bacteria interactions. A 5'-nucleotidase, which catalyze the conversion of AMP into the signal molecule adenosine, was one of these and analysis of enzymatic activity showed that L. reuteri BG-R46 derived MV exhibited the highest activity. We also detected the TLR2 activator lipoteichoic acid on the MV. In models for host interactions, we first observed that L. reuteri MV were internalized by Caco-2/HT29-MTX epithelial cells, and in a dose-dependent manner decreased the leakage caused by enterotoxigenic Escherichia coli by up to 65%. Furthermore, the MV upregulated IL-1β and IL-6 from peripheral blood mononuclear cells (PBMC), but also dampened IFN-γ and TNF-α responses in PBMC challenged with Staphylococcus aureus. Finally, we showed that MV from the L. reuteri strains have an antagonistic effect on the pain receptor transient receptor potential vanilloid 1 in a model with primary dorsal root ganglion cells from rats. In summary, we have shown that these mobile nanometer scale MV reproduce several biological effects of L. reuteri cells and that the production parameters and selection of strain have an impact on the activity of the MV. This could potentially provide key information for development of innovative and more efficient probiotic products.