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10 pages, 1165 KiB  
Brief Report
Serum Amyloid A3 Expression Is Enhanced by Gram-Negative Bacterial Stimuli in Bovine Endometrial Epithelial Cells
by Kazuha Aoyagi, Keishi Owaki, Hiroki Sakai, Ayaka Okada and Yasuo Inoshima
Pathogens 2025, 14(8), 729; https://doi.org/10.3390/pathogens14080729 - 23 Jul 2025
Viewed by 231
Abstract
Bovine endometritis is a common postpartum disease that significantly impairs reproductive performance and reduces economic sustainability in dairy and beef cattle. It is primarily caused by gram-negative and -positive bacteria, triggering strong inflammatory responses in the endometrium. Serum amyloid A (SAA) is an [...] Read more.
Bovine endometritis is a common postpartum disease that significantly impairs reproductive performance and reduces economic sustainability in dairy and beef cattle. It is primarily caused by gram-negative and -positive bacteria, triggering strong inflammatory responses in the endometrium. Serum amyloid A (SAA) is an acute-phase protein and precursor of amyloid A (AA) in AA amyloidosis. In cattle, multiple SAA isoforms have been identified; however, the biological functions of SAA3 remain unclear. Hence, this study investigated the role of SAA3 in bovine endometrial epithelial cells (BEnEpCs) following stimulation with gram-negative or -positive bacterial antigens. BEnEpCs were treated with lipopolysaccharide (LPS) and lipoteichoic acid (LTA) and, subsequently, the expression levels of SAA3 and SAA1 mRNA were compared by real-time PCR. To further investigate protein-level changes, immunocytochemistry (ICC) was performed to assess the expressions of SAA3 and SAA1. These analyses revealed that SAA3 mRNA expression was significantly enhanced by LPS and LTA, whereas SAA1 mRNA remained undetectable or showed only minimal responsiveness. Notably, only SAA3 protein expression increased in response to stimulation. These results indicate that SAA3 plays a crucial role in the innate immune response of BEnEpCs against gram-negative bacteria. Our in vitro findings may facilitate understanding of the innate immune activity in bovine uterus. Full article
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22 pages, 1791 KiB  
Review
Bacterial Amyloids as Hubs for Nucleic Acid Interactions: Implications and Mechanisms
by Sylwia Bloch, Gaelle Loutfi, Gautier Moroy, Richard R. Sinden, Grzegorz Węgrzyn and Véronique Arluison
Int. J. Mol. Sci. 2025, 26(14), 6560; https://doi.org/10.3390/ijms26146560 - 8 Jul 2025
Viewed by 435
Abstract
Amyloids are protein aggregates having a cross-β structure, and they reveal some unusual properties, like interactions with specific dyes and resistance to actions of detergents and proteases, as well as the capability to force some proteins to change their conformation from a soluble [...] Read more.
Amyloids are protein aggregates having a cross-β structure, and they reveal some unusual properties, like interactions with specific dyes and resistance to actions of detergents and proteases, as well as the capability to force some proteins to change their conformation from a soluble form to aggregates. The occurrence of amyloids is not restricted to humans and animals, as they also exist in microbial cells. However, contrary to animals, where amyloids are usually pathological molecules, bacterial amyloids are often functional, participating in various physiological processes. In this review, we focus on a specific property of bacterial amyloids, namely their ability to interact with nucleic acids and resultant regulatory mechanisms. Moreover, some of these interactions might play indirect roles in the pathomechanisms of human neurodegenerative and inflammatory diseases; these aspects are also summarized and discussed in this review. Full article
(This article belongs to the Special Issue Advances in Protein–Ligand Interactions)
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29 pages, 4036 KiB  
Article
Lipopolysaccharide and Recombinant Prion Protein Induce Distinct Neurodegenerative Pathologies in FVB/N Mice
by Seyed Ali Goldansaz, Dagnachew Hailemariam, Elda Dervishi, Grzegorz Zwierzchowski, Roman Wójcik, David S. Wishart and Burim N. Ametaj
Int. J. Mol. Sci. 2025, 26(13), 6245; https://doi.org/10.3390/ijms26136245 - 28 Jun 2025
Viewed by 406
Abstract
Prion diseases are classically attributed to the accumulation of protease-resistant prion protein (PrPSc); however, recent evidence suggests that alternative misfolded prion conformers and systemic inflammatory factors may also contribute to neurodegeneration. This study investigated whether recombinant moPrPRes, generated by [...] Read more.
Prion diseases are classically attributed to the accumulation of protease-resistant prion protein (PrPSc); however, recent evidence suggests that alternative misfolded prion conformers and systemic inflammatory factors may also contribute to neurodegeneration. This study investigated whether recombinant moPrPRes, generated by incubating wild-type mouse PrPC with bacterial lipopolysaccharide (LPS), can induce prion-like disease in FVB/N female mice, whether LPS alone causes neurodegeneration, and how LPS modulates disease progression in mice inoculated with the Rocky Mountain Laboratory (RML) strain of prions. Wild-type female FVB/N mice were randomized into six subcutaneous treatment groups: saline, LPS, moPrPRes, moPrPRes + LPS, RML, and RML + LPS. Animals were monitored longitudinally for survival, body weight, and clinical signs. Brain tissues were analyzed histologically and immunohistochemically for vacuolar degeneration, PrPSc accumulation, reactive astrogliosis, and amyloid-β plaque deposition. Recombinant moPrPRes induced a progressive spongiform encephalopathy characterized by widespread vacuolation and astrogliosis, yet with no detectable PrPSc by Western blot or immunohistochemistry. LPS alone triggered a distinct neurodegenerative phenotype, including cerebellar amyloid-β plaque accumulation and terminal-stage spongiosis, with approximately 40% mortality by the end of the study. Co-administration of moPrPRes and LPS resulted in variable regional pathology and intermediate survival (50% at 750 days post-inoculation). Interestingly, RML + LPS co-treatment led to earlier clinical onset and mortality compared to RML alone; however, vacuolation levels were not significantly elevated and, in some brain regions, were reduced. These results demonstrate that chronic endotoxemia and non-infectious misfolded PrP conformers can independently or synergistically induce key neuropathological hallmarks of prion disease, even in the absence of classical PrPSc. Targeting inflammatory signaling and toxic prion intermediates may offer novel therapeutic strategies for prion and prion-like disorders. Full article
(This article belongs to the Special Issue Advanced Research on Immune Cells and Cytokines (2nd Edition))
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13 pages, 1991 KiB  
Article
Host Serum Amyloid A1 Facilitates Streptococcus pneumoniae Adaptation to Acidic Stress Induced by Pneumococcal Anaerobic Metabolism
by Weichen Gong, Masayuki Ono, Tomoko Sumitomo, Momoko Kobayashi, Yujiro Hirose and Shigetada Kawabata
Microorganisms 2025, 13(6), 1309; https://doi.org/10.3390/microorganisms13061309 - 4 Jun 2025
Viewed by 556
Abstract
Streptococcus pneumoniae (S. pneumoniae) is a leading cause of pneumonia, and its interaction with host acute-phase proteins remains underexplored. Serum amyloid A1 (SAA1), an acute-phase protein, plays a crucial role in immune modulation. This study investigates the role of SAA1 in [...] Read more.
Streptococcus pneumoniae (S. pneumoniae) is a leading cause of pneumonia, and its interaction with host acute-phase proteins remains underexplored. Serum amyloid A1 (SAA1), an acute-phase protein, plays a crucial role in immune modulation. This study investigates the role of SAA1 in the early stages of respiratory infection by S. pneumoniae and its potential contribution to bacterial adaptation under acidic stress. We used a murine nasal infection model to simulate the early phase of S. pneumoniae invasion into the lower respiratory tract. Levels of SAA1 and C-reactive protein (CRP) in bronchoalveolar lavage fluid (BALF) and serum were quantified using ELISA. In vitro assays examined the effect of serum and recombinant SAA1 on bacterial survival under acidic conditions. Fluorescence-labeled recombinant SAA1 and microscopy were utilized to assess SAA1 internalized by S. pneumoniae. Following nasal infection, SAA1 levels in BALF were significantly reduced, whereas CRP levels remained unchanged. In vitro, serum enhanced S. pneumoniae’s resistance to acidic byproducts including formic, lactic, and acetic acids. Specifically, formic acid promoted bacterial uptake of SAA1, and this internalization improved bacterial tolerance to acidic conditions. Fluorescence microscopy confirmed that SAA1 is internalized by S. pneumoniae. S. pneumoniae can internalize SAA1 to bolster resistance to acid stress, particularly formic acid. This study reveals a novel host–pathogen interaction mechanism wherein S. pneumoniae exploits host acute-phase proteins for environmental adaptation, offering new insights into bacterial survival strategies during infection. Full article
(This article belongs to the Section Medical Microbiology)
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17 pages, 8541 KiB  
Article
Characterization of Immune Response Against Mycobacterium marinum Infection in Coho Salmon (Oncorhynchus kisutch)
by Le Li, Danlei Xu, Xiaoqing Yu, Chunlei Gai, Haibin Ye and Jing Diao
Fishes 2025, 10(6), 268; https://doi.org/10.3390/fishes10060268 - 3 Jun 2025
Viewed by 324
Abstract
Mycobacterium marinum is an opportunistic pathogen prevalent in aquatic environments, causing significant morbidity in fish, including Coho salmon (Oncorhynchus kisutch), a species increasingly cultured in Chinese salmonid aquaculture. This study investigated the immune response of Coho salmon to M. marinum infection [...] Read more.
Mycobacterium marinum is an opportunistic pathogen prevalent in aquatic environments, causing significant morbidity in fish, including Coho salmon (Oncorhynchus kisutch), a species increasingly cultured in Chinese salmonid aquaculture. This study investigated the immune response of Coho salmon to M. marinum infection and the bacterial proliferation dynamics in the liver and kidney. Transcriptome analysis revealed 5028 differentially expressed genes (DEGs) in the kidney and 3419 DEGs in the liver at 6 weeks post-infection. Gene Ontology and KEGG enrichment analysis highlighted pathways such as cytokine–cytokine receptor interaction, metabolic pathways, and Toll-like receptor signaling in the kidney, while the DEGs in the liver were enriched in metabolic pathways, immune system processes, and stress and defense responses. The temporal expression profiling of 15 immune-related genes, including acute-phase proteins (serum amyloid A-5 and hepcidin), cytokines (TNF-α, IL-1β, IL-17A), chemokines (CXCL13 and CCL19), pattern recognition receptors (Toll-like receptor 13), and other immune-related genes, showed significant upregulation against M. marinum infection, with stronger responses in the liver. Furthermore, it was found that there was a progressive proliferation of M. marinum in the infected liver and kidney from approximately 2.5 log10 cfu/g at week 2 to about 6 log10 cfu/g by 6 weeks, with a significantly higher load in the liver. These findings provide critical insights into the immune mechanisms of Coho salmon against M. marinum and the pathogen’s tissue-specific proliferation, offering a foundation for developing targeted control strategies against M. marinum in aquaculture. Full article
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17 pages, 844 KiB  
Review
Role of Phages in Past Molecular Biology and Potentially in Future Biomedicine
by Philip Serwer
Encyclopedia 2025, 5(2), 58; https://doi.org/10.3390/encyclopedia5020058 - 4 May 2025
Viewed by 1159
Abstract
Viruses that infect bacteria (bacteriophages or phages) have a history of use in both biomedicine and basic molecular biology. Here, I briefly outline the pre-1940 use of phages in biomedicine and then more comprehensively outline the subsequent use of phages in determining the [...] Read more.
Viruses that infect bacteria (bacteriophages or phages) have a history of use in both biomedicine and basic molecular biology. Here, I briefly outline the pre-1940 use of phages in biomedicine and then more comprehensively outline the subsequent use of phages in determining the basics of molecular biology. Finally, I outline work that appears to form the foundation for a future, phage-enhanced biomedicine that generally extends medicine in the areas of anti-bacterial therapy (including vaccinology), anti-tumor therapy, and understanding the basic process of amyloid-associated neurodegenerative diseases. The following are general conclusions. (1) In the future, the discipline of phage-based biomedicine will be enhanced by more extensive merging with the discipline of basic phage biology (including molecular biology) and evolution. These two disciplines have been separated post-1940. (2) Biomedicine, in general, will be assisted if the focus is on key problems and key observations, thereby leaving details to later work. (3) Simplicity of strategy is a virtue that can be implemented and should be pursued with phages. (4) Capacity for directed evolution provides phages with generative (artificial intelligence-like) means for increasing biomedical effectiveness without using human design. Two related quotes set the stage (references at the end of the text). “But see that the imagination of nature is far, far greater than the imagination of man” (physicist Richard Feynman). “Nature, in all its variations and seeming paradoxes, speaks to those who pay attention and gives hints and clues to basic facts” (a thought attributed to Felix d’Herelle, a self-trained biologist who developed biological phage isolation and characterization). The integration of natural phenomenon-focused basic science and medical practice is an underlying theme. Full article
(This article belongs to the Section Biology & Life Sciences)
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136 pages, 24434 KiB  
Perspective
Alzheimer’s Is a Multiform Disease of Sustained Neuronal Integrated Stress Response Driven by the C99 Fragment Generated Independently of AβPP; Proteolytic Production of Aβ Is Suppressed in AD-Affected Neurons: Evolution of a Theory
by Vladimir Volloch and Sophia Rits-Volloch
Int. J. Mol. Sci. 2025, 26(9), 4252; https://doi.org/10.3390/ijms26094252 - 29 Apr 2025
Viewed by 1342
Abstract
The present Perspective analyzes the remarkable evolution of the Amyloid Cascade Hypothesis 2.0 (ACH2.0) theory of Alzheimer’s disease (AD) since its inception a few years ago, as reflected in the diminishing role of amyloid-beta (Aβ) in the disease. In the initial iteration of [...] Read more.
The present Perspective analyzes the remarkable evolution of the Amyloid Cascade Hypothesis 2.0 (ACH2.0) theory of Alzheimer’s disease (AD) since its inception a few years ago, as reflected in the diminishing role of amyloid-beta (Aβ) in the disease. In the initial iteration of the ACH2.0, Aβ-protein-precursor (AβPP)-derived intraneuronal Aβ (iAβ), accumulated to neuronal integrated stress response (ISR)-eliciting levels, triggers AD. The neuronal ISR, in turn, activates the AβPP-independent production of its C99 fragment that is processed into iAβ, which drives the disease. The second iteration of the ACH2.0 stemmed from the realization that AD is, in fact, a disease of the sustained neuronal ISR. It introduced two categories of AD—conventional and unconventional—differing mainly in the manner of their causation. The former is caused by the neuronal ISR triggered by AβPP-derived iAβ, whereas in the latter, the neuronal ISR is elicited by stressors distinct from AβPP-derived iAβ and arising from brain trauma, viral and bacterial infections, and various types of inflammation. Moreover, conventional AD always contains an unconventional component, and in both forms, the disease is driven by iAβ generated independently of AβPP. In its third, the current, iteration, the ACH2.0 posits that proteolytic production of Aβ is suppressed in AD-affected neurons and that the disease is driven by C99 generated independently of AβPP. Suppression of Aβ production in AD seems an oxymoron: Aβ is equated with AD, and the later is inconceivable without the former in an ingrained Amyloid Cascade Hypothesis (ACH)-based notion. But suppression of Aβ production in AD-affected neurons is where the logic leads, and to follow it we only need to overcome the inertia of the preexisting assumptions. Moreover, not only is the generation of Aβ suppressed, so is the production of all components of the AβPP proteolytic pathway. This assertion is not a quantum leap (unless overcoming the inertia counts as such): the global cellular protein synthesis is severely suppressed under the neuronal ISR conditions, and there is no reason for constituents of the AβPP proteolytic pathway to be exempted, and they, apparently, are not, as indicated by the empirical data. In contrast, tau protein translation persists in AD-affected neurons under ISR conditions because the human tau mRNA contains an internal ribosomal entry site in its 5′UTR. In current mouse models, iAβ derived from AβPP expressed exogenously from human transgenes elicits the neuronal ISR and thus suppresses its own production. Its levels cannot principally reach AD pathology-causing levels regardless of the number of transgenes or the types of FAD mutations that they (or additional transgenes) carry. Since the AβPP-independent C99 production pathway is inoperative in mice, the current transgenic models have no potential for developing the full spectrum of AD pathology. What they display are only effects of the AβPP-derived iAβ-elicited neuronal ISR. The paper describes strategies to construct adequate transgenic AD models. It also details the utilization of human neuronal cells as the only adequate model system currently available for conventional and unconventional AD. The final alteration of the ACH2.0, introduced in the present Perspective, is that AβPP, which supports neuronal functionality and viability, is, after all, potentially produced in AD-affected neurons, albeit not conventionally but in an ISR-driven and -compatible process. Thus, the present narrative begins with the “omnipotent” Aβ capable of both triggering and driving the disease and ends up with this peptide largely dislodged from its pedestal and retaining its central role in triggering the disease in only one, although prevalent (conventional), category of AD (and driving it in none). Among interesting inferences of the present Perspective is the determination that “sporadic AD” is not sporadic at all (“non-familial” would be a much better designation). The term has fatalistic connotations, implying that the disease can strike at random. This is patently not the case: The conventional disease affects a distinct subpopulation, and the basis for unconventional AD is well understood. Another conclusion is that, unless prevented, the occurrence of conventional AD is inevitable given a sufficiently long lifespan. This Perspective also defines therapeutic directions not to be taken as well as auspicious ways forward. The former category includes ACH-based drugs (those interfering with the proteolytic production of Aβ and/or depleting extracellular Aβ). They are legitimate (albeit inefficient) preventive agents for conventional AD. There is, however, a proverbial snowball’s chance in hell of them being effective in symptomatic AD, lecanemab, donanemab, and any other “…mab” or “…stat” notwithstanding. They comprise Aβ-specific antibodies, inhibitors of beta- and gamma-secretase, and modulators of the latter. In the latter category, among ways to go are the following: (1) Depletion of iAβ, which, if sufficiently “deep”, opens up a tantalizing possibility of once-in-a-lifetime preventive transient treatment for conventional AD and aging-associated cognitive decline, AACD. (2) Composite therapy comprising the degradation of C99/iAβ and concurrent inhibition of the neuronal ISR. A single transient treatment could be sufficient to arrest the progression of conventional AD and prevent its recurrence for life. Multiple recurrent treatments would achieve the same outcome in unconventional AD. Alternatively, the sustained reduction/removal of unconventional neuronal ISR-eliciting stressors through the elimination of their source would convert unconventional AD into conventional one, preventable/treatable by a single transient administration of the composite C99/iAβ depletion/ISR suppression therapy. Efficient and suitable ISR inhibitors are available, and it is explicitly clear where to look for C99/iAβ-specific targeted degradation agents—activators of BACE1 and, especially, BACE2. Directly acting C99/iAβ-specific degradation agents such as proteolysis-targeting chimeras (PROTACs) and molecular-glue degraders (MGDs) are also viable options. (3) A circumscribed shift (either upstream or downstream) of the position of transcription start site (TSS) of the human AβPP gene, or, alternatively, a gene editing-mediated excision or replacement of a small, defined segment of its portion encoding 5′-untranslated region of AβPP mRNA; targeting AβPP RNA with anti-antisense oligonucleotides is another possibility. If properly executed, these RNA-based strategies would not interfere with the protein-coding potential of AβPP mRNA, and each would be capable of both preventing and stopping the AβPP-independent generation of C99 and thus of either preventing AD or arresting the progression of the disease in its conventional and unconventional forms. The paper is interspersed with “validation” sections: every conceptually significant notion is either validated by the existing data or an experimental procedure validating it is proposed. Full article
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23 pages, 6538 KiB  
Review
Biofilm-Associated Amyloid Proteins Linked with the Progression of Neurodegenerative Diseases
by Alka Ashok Singh, Fazlurrahman Khan and Minseok Song
Int. J. Mol. Sci. 2025, 26(6), 2695; https://doi.org/10.3390/ijms26062695 - 17 Mar 2025
Cited by 1 | Viewed by 1538
Abstract
Biofilm-associated amyloid proteins have emerged as significant contributors to the progression of neurodegenerative diseases, representing a complex intersection of microorganisms and human health. The cross-beta sheet structure characteristic of amyloids produced by gut-colonizing bacteria remains intact, crucial for the resilience of biofilms. These [...] Read more.
Biofilm-associated amyloid proteins have emerged as significant contributors to the progression of neurodegenerative diseases, representing a complex intersection of microorganisms and human health. The cross-beta sheet structure characteristic of amyloids produced by gut-colonizing bacteria remains intact, crucial for the resilience of biofilms. These amyloids exacerbate neurodegenerative disorders such as Alzheimer’s and Parkinson’s by cross-seeding human amyloidogenic proteins like amyloid-beta and α-synuclein, accelerating their misfolding and aggregation. Despite molecular chaperones and heat shock proteins maintaining protein homeostasis, bacterial amyloids can overwhelm them, worsening neuronal damage. Genetic variations in chaperone genes further influence amyloidogenesis and neurodegeneration. Persistent bacterial infections and inflammation compromise the blood-brain barrier, allowing inflammatory molecules and amyloids to enter the brain, perpetuating the cycle of neurodegeneration. The gut-brain axis underscores the impact of dysbiosis and gut microbiota on brain function, potentially contributing to neurodegeneration. The enhancement of biofilm resilience and antibiotic resistance by functional amyloid fibrils complicates the treatment landscape. The interplay among chaperone systems, microbial amyloids, and neurodegenerative diseases underscores the urgent need for advanced treatment strategies targeting these pathways to attenuate disease progression. Understanding the processes that relate biofilm-associated amyloids to the onset of neurological disorders is critical for diagnosing and developing novel treatment strategies. Full article
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28 pages, 1085 KiB  
Review
Microbial Influences on Amyotrophic Lateral Sclerosis: The Gut–Brain Axis and Therapeutic Potential of Microbiota Modulation
by Victòria Ayala, Laia Fontdevila, Santiago Rico-Rios, Mònica Povedano, Pol Andrés-Benito, Pascual Torres, José C. E. Serrano, Reinald Pamplona and Manuel Portero-Otin
Sclerosis 2025, 3(1), 8; https://doi.org/10.3390/sclerosis3010008 - 5 Mar 2025
Cited by 2 | Viewed by 1414
Abstract
Background/Objectives: Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder characterized by the progressive degeneration of motor neurons. The gut microbiota, a community of microorganisms in the digestive tract, has recently been implicated in ALS pathogenesis through its influence on neuroinflammation and metabolic pathways. [...] Read more.
Background/Objectives: Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder characterized by the progressive degeneration of motor neurons. The gut microbiota, a community of microorganisms in the digestive tract, has recently been implicated in ALS pathogenesis through its influence on neuroinflammation and metabolic pathways. This review explores the potential role of digestive microbiota and its metabolites in ALS progression and investigates therapeutic approaches targeting gut microbiota. Methods: A comprehensive review of the current literature was conducted to assess the relationship between gut microbiota composition, microbial metabolites, and ALS progression in patients. We searched for published reports on microbiota composition, microbial metabolites, and ALS, emphasizing the complex interplay between dysbiosis, neuroinflammation, and systemic metabolism. Special emphasis was placed on studies exploring short-chain fatty acids (SCFAs), bacterial amyloids (curli-like factors), and neurotoxins such as β-methylamino-L-alanine (BMAA). The role of the liver–gut axis was evaluated as well. The potential changes in microbiota would sustain the rationale for therapeutic strategies such as probiotics, prebiotics, fecal microbiota transplantation (FMT), and dietary interventions. Results: ALS patients exhibit gut dysbiosis, characterized by reduced SCFA-producing bacteria and an increase in potentially pathogenic genera. Of note, different studies do not agree on common patterns of microbiota being linked to ALS, supporting the need for further, more extensive studies. Dysbiosis sometimes correlates with systemic inflammation and disrupted liver function, amplifying neuroinflammatory responses. Key microbial metabolites, including SCFAs, bacterial amyloids, and BMAA, may exacerbate motor neuron degeneration by promoting protein misfolding, oxidative stress, and neuroinflammation. Emerging therapeutic strategies, including probiotics and FMT, show potential in restoring microbial balance, although clinical data in ALS patients remain limited. Conclusions: The gut microbiota could modulate neuroinflammation and systemic metabolism in ALS. Microbiota-targeted therapies, such as probiotics and dietary interventions, represent promising avenues for mitigating disease progression. Further research is required to validate these interventions through large-scale, longitudinal studies and to develop personalized microbiota-based treatments tailored to individual ALS phenotypes. Full article
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9 pages, 2144 KiB  
Communication
A Method for Demonstrating the Cytolysin/Hemolysin of Enterococcus faecalis Isolates of Poultry Origin
by Donald L. Reynolds, E. Barry Simpson and Matthew M. Hille
Poultry 2025, 4(1), 11; https://doi.org/10.3390/poultry4010011 - 26 Feb 2025
Cited by 1 | Viewed by 959
Abstract
Enterococcus faecalis (E. faecalis) is a ubiquitous microbe occurring in the environment and in the intestinal tract of poultry. E. faecalis has been identified in cases of egg infertility and/or decreased hatchability and can cause amyloid arthropathy in older laying chickens. [...] Read more.
Enterococcus faecalis (E. faecalis) is a ubiquitous microbe occurring in the environment and in the intestinal tract of poultry. E. faecalis has been identified in cases of egg infertility and/or decreased hatchability and can cause amyloid arthropathy in older laying chickens. E. faecalis produces cytolysin, a bacterial exotoxin that can cause lysis of erythrocytes. It has been difficult to demonstrate this virulence trait using conventional culture methods with sheep blood agar. A 96-well microplate hemolysis assay, along with a culture method incorporating glucose and L-arginine into the culture media, is described that demonstrates the production of cytolysin in E. faecalis isolates of avian origin. Additionally, the results show that horse and sheep erythrocytes were susceptible to lysis by the E. faecalis cytolysin, but cow and chicken erythrocytes were less susceptible. Full article
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19 pages, 1269 KiB  
Article
Augmenting Cognitive Function in the Elderly with Mild Cognitive Impairment Using Probiotic Lacticaseibacillus rhamnosus CBT-LR5: A 12-Week Randomized, Double-Blind, Parallel-Group Non-Comparative Study
by Su-Jin Jung, Kyohee Cho, Eun-Soo Jung, Dooheon Son, Jong-Seon Byun, Song-In Kim, Soo-Wan Chae, Jong-Chul Yang, Seung-Ok Lee and Sanghyun Lim
Nutrients 2025, 17(4), 691; https://doi.org/10.3390/nu17040691 - 14 Feb 2025
Cited by 1 | Viewed by 3640
Abstract
Background: Probiotics have been shown to enhance cognitive function in individuals with mild cognitive impairment (MCI), but their efficacy varies, depending on the strain and dosage. Objectives: Clinical investigations are crucial to confirm their safety, efficacy, and mechanism of action. This study was [...] Read more.
Background: Probiotics have been shown to enhance cognitive function in individuals with mild cognitive impairment (MCI), but their efficacy varies, depending on the strain and dosage. Objectives: Clinical investigations are crucial to confirm their safety, efficacy, and mechanism of action. This study was designed to assess the effective dosage, safety, and efficacy of MH-Pro, a test product containing Lacticaseibacillus rhamnosus CBT-LR5 (LR5) and skim milk (non-fat dry milk), in improving cognitive function and related physiological changes in older adults suspected of MCI over 12 weeks. Methods: In total, 20 participants (mean age: 68.9 years) were randomly assigned in a 1:1 ratio to either a low-dose group (1 × 1010 CFU LR5 with 1622 mg) or a high-dose group (1 × 1010 CFU LR5 with 4055 mg skim milk) in a double-blind, parallel-group clinical trial. Results: After 12 weeks, the low-dose group showed significant improvements in the MOCA-K subdomains, specifically in naming (p = 0.01) and delayed recall (p = 0.003). Additionally, levels of amyloid-β1 40/42 in the blood significantly decreased (p = 0.03) following supplementation in the low-dose group. The high-dose group exhibited significant improvement in orientation (p = 0.05). Moreover, overall cognitive enhancement was observed in the low-dose group (p = 0.003), while the high-dose group showed a trend toward improvement (p = 0.06). Fecal analysis revealed significant changes in bacterial composition, with an increase in Lacticaseibacillus after 12 weeks of MH-Pro consumption. Together, these findings provide foundational evidence suggesting that MH-Pro supplementation may serve as a potential intervention for enhancing cognitive function through gut–brain axis pathways in the elderly population. However, given the small sample size and the predominance of female participants, the impact of the outcome may be limited. Further large-scale studies are necessary to validate these preliminary results. Conclusions: This study provides foundational evidence to recognize the use of LR5 and skim milk to prepare a probiotic supplement that enhances cognitive function in the aging population. Full article
(This article belongs to the Special Issue Diet, Gut Microbiota and Neuropsychiatric Diseases)
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23 pages, 1248 KiB  
Review
The Role of the Hfq Protein in Bacterial Resistance to Antibiotics: A Narrative Review
by Sylwia Bloch, Grzegorz Węgrzyn and Véronique Arluison
Microorganisms 2025, 13(2), 364; https://doi.org/10.3390/microorganisms13020364 - 7 Feb 2025
Cited by 3 | Viewed by 1617
Abstract
The antibiotic resistance of pathogenic microorganisms is currently one of most major medical problems, causing a few million deaths every year worldwide due to untreatable bacterial infections. Unfortunately, the prognosis is even worse, as over 8 million deaths associated with antibiotic resistance are [...] Read more.
The antibiotic resistance of pathogenic microorganisms is currently one of most major medical problems, causing a few million deaths every year worldwide due to untreatable bacterial infections. Unfortunately, the prognosis is even worse, as over 8 million deaths associated with antibiotic resistance are expected to occur in 2050 if no new effective antibacterial treatments are discovered. The Hfq protein has been discovered as a bacterial RNA chaperone. However, subsequent studies have indicated that this small protein (composed of 102 amino acid residues in Escherichia coli) has more activities, including binding to DNA and influencing its compaction, interaction with biological membranes, formation of amyloid-like structures, and others. Although Hfq is known to participate in many cellular processes, perhaps surprisingly, only reports from recent years have demonstrated its role in bacterial antibiotic resistance. The aim of this narrative review is to discuss how can Hfq affects antibiotic resistance in bacteria and propose how this knowledge may facilitate developing new therapeutic strategies against pathogenic bacteria. We indicate that the mechanisms by which the Hfq protein modulates the response of bacterial cells to antibiotics are quite different, from the regulation of the expression of genes coding for proteins directly involved in antibiotic transportation or action, through direct effects on membranes, to controlling the replication or transposition of mobile genetic elements bearing antibiotic resistance genes. Therefore, we suggest that Hfq could be considered a potential target for novel antimicrobial compounds. We also discuss difficulties in developing such drugs, but since Hfq appears to be a promising target for drugs that may enhance the efficacy of antibiotics, we propose that works on such potential therapeutics are encouraged. Full article
(This article belongs to the Special Issue Clinical Microbial Infection and Antimicrobial Resistance)
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19 pages, 1493 KiB  
Review
Gut-Heart Axis: Microbiome Involvement in Restrictive Cardiomyopathies
by Samuel Jaimez-Alvarado, Itzel Ivonn López-Tenorio, Javier Barragán-De los Santos, Dannya Coral Bello-Vega, Francisco Javier Roldán Gómez, Amedeo Amedei, Enrique Alexander Berrios-Bárcenas and María Magdalena Aguirre-García
Biomedicines 2025, 13(1), 144; https://doi.org/10.3390/biomedicines13010144 - 9 Jan 2025
Cited by 2 | Viewed by 2363
Abstract
An intriguing aspect of restrictive cardiomyopathies (RCM) is the microbiome role in the natural history of the disease. These cardiomyopathies are often difficult to diagnose and so result in significant morbidity and mortality. The human microbiome, composed of billions of microorganisms, influences various [...] Read more.
An intriguing aspect of restrictive cardiomyopathies (RCM) is the microbiome role in the natural history of the disease. These cardiomyopathies are often difficult to diagnose and so result in significant morbidity and mortality. The human microbiome, composed of billions of microorganisms, influences various physiological and pathological processes, including cardiovascular health. Studies have shown that gut dysbiosis, an imbalance in the composition of intestinal bacteria, can contribute to systemic inflammation, a key factor in many cardiovascular conditions. An increase in gut permeability, frequently caused by dysbiosis, allows bacterial endotoxins to enter the bloodstream, activating inflammatory pathways that exacerbate cardiac dysfunction. Recent reports highlight the potential role of microbiome in amyloidogenesis, as certain bacteria produce proteins that accelerate the formation of amyloid fibrils. Concurrently, advancements in amyloidosis treatments have sparked renewed hopes, marking a promising era for managing these kinds of diseases. These findings suggest that the gut–heart axis may be a potential factor in the development and progression of cardiovascular disease like RCM, opening new paths for therapeutic intervention. The aim of this review is to provide a detailed overview of the gut–heart axis, focusing on RCM. Full article
(This article belongs to the Special Issue Cardiomyopathies and Heart Failure: Charting the Future)
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32 pages, 1321 KiB  
Review
Shattering the Amyloid Illusion: The Microbial Enigma of Alzheimer’s Disease Pathogenesis—From Gut Microbiota and Viruses to Brain Biofilms
by Anna Onisiforou, Eleftheria G. Charalambous and Panos Zanos
Microorganisms 2025, 13(1), 90; https://doi.org/10.3390/microorganisms13010090 - 5 Jan 2025
Cited by 6 | Viewed by 5158
Abstract
For decades, Alzheimer’s Disease (AD) research has focused on the amyloid cascade hypothesis, which identifies amyloid-beta (Aβ) as the primary driver of the disease. However, the consistent failure of Aβ-targeted therapies to demonstrate efficacy, coupled with significant safety concerns, underscores the need to [...] Read more.
For decades, Alzheimer’s Disease (AD) research has focused on the amyloid cascade hypothesis, which identifies amyloid-beta (Aβ) as the primary driver of the disease. However, the consistent failure of Aβ-targeted therapies to demonstrate efficacy, coupled with significant safety concerns, underscores the need to rethink our approach to AD treatment. Emerging evidence points to microbial infections as environmental factors in AD pathoetiology. Although a definitive causal link remains unestablished, the collective evidence is compelling. This review explores unconventional perspectives and emerging paradigms regarding microbial involvement in AD pathogenesis, emphasizing the gut–brain axis, brain biofilms, the oral microbiome, and viral infections. Transgenic mouse models show that gut microbiota dysregulation precedes brain Aβ accumulation, emphasizing gut–brain signaling pathways. Viral infections like Herpes Simplex Virus Type 1 (HSV-1) and Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) may lead to AD by modulating host processes like the immune system. Aβ peptide’s antimicrobial function as a response to microbial infection might inadvertently promote AD. We discuss potential microbiome-based therapies as promising strategies for managing and potentially preventing AD progression. Fecal microbiota transplantation (FMT) restores gut microbial balance, reduces Aβ accumulation, and improves cognition in preclinical models. Probiotics and prebiotics reduce neuroinflammation and Aβ plaques, while antiviral therapies targeting HSV-1 and vaccines like the shingles vaccine show potential to mitigate AD pathology. Developing effective treatments requires standardized methods to identify and measure microbial infections in AD patients, enabling personalized therapies that address individual microbial contributions to AD pathogenesis. Further research is needed to clarify the interactions between microbes and Aβ, explore bacterial and viral interplay, and understand their broader effects on host processes to translate these insights into clinical interventions. Full article
(This article belongs to the Special Issue Latest Review Papers in Medical Microbiology 2024)
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27 pages, 3932 KiB  
Article
Evaluation of the Anti-Amyloid and Anti-Inflammatory Properties of a Novel Vanadium(IV)–Curcumin Complex in Lipopolysaccharides-Stimulated Primary Rat Neuron-Microglia Mixed Cultures
by Georgios Katsipis, Sophia N. Lavrentiadou, George D. Geromichalos, Maria P. Tsantarliotou, Eleftherios Halevas, George Litsardakis and Anastasia A. Pantazaki
Int. J. Mol. Sci. 2025, 26(1), 282; https://doi.org/10.3390/ijms26010282 - 31 Dec 2024
Cited by 3 | Viewed by 1549
Abstract
Lipopolysaccharides (LPS) are bacterial mediators of neuroinflammation that have been detected in close association with pathological protein aggregations of Alzheimer’s disease. LPS induce the release of cytokines by microglia and mediate the upregulation of inducible nitric oxide synthase (iNOS)—a mechanism also associated with [...] Read more.
Lipopolysaccharides (LPS) are bacterial mediators of neuroinflammation that have been detected in close association with pathological protein aggregations of Alzheimer’s disease. LPS induce the release of cytokines by microglia and mediate the upregulation of inducible nitric oxide synthase (iNOS)—a mechanism also associated with amyloidosis. Curcumin is a recognized natural medicine but has extremely low bioavailability. V-Cur, a novel hemocompatible Vanadium(IV)-curcumin complex with higher solubility and bioactivity than curcumin, is studied here. Co-cultures consisting of rat primary neurons and microglia were treated with LPS and/or curcumin or V-Cur. V-Cur disrupted LPS-induced overexpression of amyloid precursor protein (APP) and the in vitro aggregation of human insulin (HI), more effectively than curcumin. Cell stimulation with LPS also increased full-length, inactive, and total iNOS levels, and the inflammation markers IL-1β and TNF-α. Both curcumin and V-Cur alleviated these effects, with V-Cur reducing iNOS levels more than curcumin. Complementary insights into possible bioactivity mechanisms of both curcumin and V-Cur were provided by In silico molecular docking calculations on Aβ1-42, APP, Aβ fibrils, HI, and iNOS. This study renders curcumin-based compounds a promising anti-inflammatory intervention that may be proven a strong tool in the effort to mitigate neurodegenerative disease pathology and neuroinflammatory conditions. Full article
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