Farnesol induces protection against murine CNS inflammatory demyelination and modifies gut microbiome

Absence of farnesol salvage in Candida albicans and probably in other fungi

Farnesol salvage, a two-step pathway converting farnesol to farnesyl pyrophosphate (FPP), occurs in bacteria, plants, and animals. This paper investigates the presence of this pathway in fungi. Through bioinformatics, biochemistry, and physiological analyses, we demonstrate its absence in the yeasts Saccharomyces cerevisiae and Candida albicans, suggesting a likely absence across fungi. We screened 1,053 fungal genomes, including 34 from C. albicans, for potential homologs to four genes (Arabidopsis thaliana AtFOLK, AtVTE5, AtVTE6, and Plasmodium falciparum PfPOLK) known to accomplish farnesol/prenol salvage in other organisms. Additionally, we showed that 3H-farnesol was not converted to FPP or any other phosphorylated prenol, and exogenous farnesol was not metabolized within 90 minutes at any phase of growth and did not rescue cells from the toxic effects of atorvastatin, but it did elevate the levels of intracellular farnesol (Fi). All these experiments were conducted with C. albicans. In sum, we found no evidence for farnesol salvage in fungi.

IMPORTANCE

The absence of farnesol salvage constitutes a major difference in the metabolic capabilities of fungi. In terms of fungal physiology, the lack of farnesol salvage pathways relates to how farnesol acts as a quorum-sensing molecule in Candida albicans and why farnesol should be investigated for use in combination with other known antifungal antibiotics. Its absence is essential for a model (K. W. Nickerson et al., Microbiol Mol Biol Rev 88:e00081-22, 2024), wherein protein farnesylation, protein chaperones, and the unfolded protein response are combined under the unifying umbrella of a cell's intracellular farnesol (Fi). In terms of human health, farnesol should have at least two different modes of action depending on whether those cells have farnesol salvage. Because animals have farnesol salvage, we can now see the importance of dietary prenols as well as the potential importance of farnesol in treating neurodegenerative diseases such as Parkinson's disease, Alzheimer's disease, and multiple sclerosis.

Genetically engineered Lactococcus lactis strain constitutively expresses GABA-producing genes and produces high levels of GABA

γ-Aminobutyric acid (GABA) is an inhibitory neurotransmitter of the central nervous system that impacts physical and mental health. Low GABA levels have been documented in several diseases, including multiple sclerosis and depression, and studies suggest that GABA could improve disease outcomes in those conditions. Probiotic bacteria naturally produce GABA and have been engineered to enhance its synthesis. Strains engineered thus far use inducible expression systems that require the addition of exogenous molecules, which complicates their development as therapeutics. This study aimed to overcome this challenge by engineering Lactococcus lactis with a constitutive GABA synthesis gene cassette. GABA synthesizing and transport genes (gadB and gadC) were cloned onto plasmids downstream of constitutive L. lactis promoters [P2, P5, shortened P8 (P8s)] of different strengths and transformed into L. lactis. Fold increase in gadCB expression conferred by these promoters (P2, P5, and P8s) was 322, 422, and 627, respectively, compared to the unmodified strain (P = 0.0325, P8s). GABA synthesis in the highest gadCB expressing strain, L. lactis-P8s-glutamic acid decarboxylase (GAD), was dependent on media supplementation with glutamic acid and significantly higher than the unmodified strain (P < 0.0001, 125 mM, 200 mM glutamic acid). Lactococcus lactis-P8s-GAD is poised for therapeutic testing in animal models of low-GABA-associated disease.

Gut microbiota in multiple sclerosis and animal models

Multiple sclerosis (MS) is a chronic central nervous system (CNS) neurodegenerative and neuroinflammatory disease marked by a host immune reaction that targets and destroys the neuronal myelin sheath. MS and correlating animal disease models show comorbidities, including intestinal barrier disruption and alterations of the commensal microbiome. It is accepted that diet plays a crucial role in shaping the microbiota composition and overall gastrointestinal (GI) tract health, suggesting an interplay between nutrition and neuroinflammation via the gut-brain axis. Unfortunately, poor host health and diet lead to microbiota modifications that could lead to significant responses in the host, including inflammation and neurobehavioral changes. Beneficial microbial metabolites are essential for host homeostasis and inflammation control. This review will highlight the importance of the gut microbiota in the context of host inflammatory responses in MS and MS animal models. Additionally, microbial community restoration and how it affects MS and GI barrier integrity will be discussed.

Physiological adventures in Candida albicans: farnesol and ubiquinones

SUMMARYFarnesol was first identified as a quorum-sensing molecule, which blocked the yeast to hyphal transition in Candida albicans, 22 years ago. However, its interactions with Candida biology are surprisingly complex. Exogenous (secreted or supplied) farnesol can also act as a virulence factor during pathogenesis and as a fungicidal agent triggering apoptosis in other competing fungi. Farnesol synthesis is turned off both during anaerobic growth and in opaque cells. Distinctly different cellular responses are observed as exogenous farnesol levels are increased from 0.1 to 100 µM. Reported changes include altered morphology, stress response, pathogenicity, antibiotic sensitivity/resistance, and even cell lysis. Throughout, there has been a dearth of mechanisms associated with these observations, in part due to the absence of accurate measurement of intracellular farnesol levels (Fi). This obstacle has recently been overcome, and the above phenomena can now be viewed in terms of changing Fi levels and the percentage of farnesol secreted. Critically, two aspects of isoprenoid metabolism present in higher organisms are absent in C. albicans and likely in other yeasts. These are pathways for farnesol salvage (converting farnesol to farnesyl pyrophosphate) and farnesylcysteine cleavage, a necessary step in the turnover of farnesylated proteins. Together, these developments suggest a unifying model, whereby high, threshold levels of Fi regulate which target proteins are farnesylated or the extent to which they are farnesylated. Thus, we suggest that the diversity of cellular responses to farnesol reflects the diversity of the proteins that are or are not farnesylated.

Lachnospiraceae are emerging industrial biocatalysts and biotherapeutics

The Lachnospiraceae is a family of anaerobic bacteria in the class Clostridia with potential to advance the bio-economy and intestinal therapeutics. Some species of Lachnospiraceae metabolize abundant, low-cost feedstocks such as lignocellulose and carbon dioxide into value-added chemicals. Others are among the dominant species of the human colon and animal rumen, where they ferment dietary fiber to promote healthy gut and immune function. Here, we summarize recent studies of the physiology, cultivation, and genetics of Lachnospiraceae, highlighting their wide substrate utilization and metabolic products with industrial applications. We examine studies of these bacteria as Live Biotherapeutic Products (LBPs), focusing on in vivo disease models and clinical studies using them to treat infection, inflammation, metabolic syndrome, and cancer. We discuss key research areas including elucidation of intra-specific diversity and genetic modification of candidate strains that will facilitate the exploitation of Lachnospiraceae in industry and medicine.

Concurrent administration of farnesol protects acetaminophen-induced acute hepatic necrosis in mice

Acetaminophen (APAP) is known to cause acute liver injury and acute liver failure in Western countries. This study investigates the protective role of farnesol (FAR) (C15 H26 O), a natural sesquiterpene alcohol in essential oils, against APAP-induced acute liver necrosis in mice. Mice were injected with a single dose of APAP (300 mg/kg) via an intraperitoneal route. Different groups of mice were concurrently treated with a single dose of FAR 25 mg/kg, FAR 50 mg/kg, and N-acetylcysteine. APAP administration caused a significant increase in transaminase activities and malondialdehyde (MDA) levels in the serum and liver tissue, respectively, with a concomitant decrease in intracellular antioxidants, including reduced glutathione (GSH) in the liver tissue. APAP intoxication upregulated proinflammatory cytokines such as tumor necrosis factor-α, interleukin-1β (IL-1β), IL-6, nuclear factor-κB (NF-κB), and IκB kinase β in the liver tissue. FAR and N-acetylcysteine (NAC) administrations concurrently with APAP prevented serum transaminase increase in serum and MDA levels in the liver tissue. A high dose of FAR and NAC treatments significantly inhibited GSH and other antioxidant depletion. FAR and NAC treatments also downregulated the expression of proinflammatory markers. FAR treatments protects against APAP-induced acute liver injury and offers antioxidant and anti-inflammatory effects by inhibiting the NF-κB pathway involved in the transcription of genes responsible for inflammatory cytokine synthesis.

Study on the Common Molecular Mechanism of Metabolic Acidosis and Myocardial Damage Complicated by Neonatal Pneumonia

Pneumonia is a common clinical disease in the neonatal period and poses a serious risk to infant health. Therefore, the understanding of molecular mechanisms is of great importance for the development of methods for the rapid and accurate identification, classification and staging, and even disease diagnosis and therapy of pneumonia. In this study, a nontargeted metabonomic method was developed and applied for the analysis of serum samples collected from 20 cases in the pneumonia control group (PN) and 20 and 10 cases of pneumonia patients with metabolic acidosis (MA) and myocardial damage (MD), respectively, with the help of ultrahigh-performance liquid chromatography-high-resolution mass spectrometry (UPLC-HRMS). The results showed that compared with the pneumonia group, 23 and 21 differential metabolites were identified in pneumonia with two complications. They showed high sensitivity and specificity, with the area under the curve (ROC) of the receiver operating characteristic curve (ROC) larger than 0.7 for each differential molecule. There were 14 metabolites and three metabolic pathways of sphingolipid metabolism, porphyrin and chlorophyll metabolism, and glycerophospholipid metabolism existing in both groups of PN and MA, and PN and MD, all involving significant changes in pathways closely related to amino acid metabolism disorders, abnormal cell apoptosis, and inflammatory responses. These findings of molecular mechanisms should help a lot to fully understand and even treat the complications of pneumonia in infants.

In Vitro Activity of Farnesol against Malassezia pachydermatis Isolates from Otitis Externa Cases in Dogs

Chronic otitis externa of dogs is a significant problem due to the prevalence and complexity of the treatment of such animals. There is evidence that in 60-80% of cases of infectious diseases microorganisms located in the biofilm phenotype play the main role. Microorganisms in the biofilm phenotype have a number of advantages, the most significant of which is considered to be increased resistance to various external factors. Among them, a special place is occupied by resistance to antibiotics. In recent decades, research has been conducted at an increasing scale on the role of biofilm infections in various pathologies in veterinary medicine. The etiology and therapy of dog otitis externa caused by Malassezia pachydermatis biofilm has not been fully studied. This is why we consider relevant the scientific and practical aspects of research on the etiology and therapy of dog otitis externa from the position of biofilm infection. In this work, it has been statistically proven that there is a relationship between the optical density of Malassezia pachydermatis biofilms and their sensitivity to drugs, and this relationship is statistically significant. In addition, we have demonstrated that Farnesol has a good antibiofilm effect at a concentration of more 1.6 μM/mL (24% OD decrease of biofilm), and its highest antibiofilm effect (71-55%-more than a half) was observed at a concentration of 200-12.5 μM/mL.

Metabolite profiling of human-originated Lachnospiraceae at the strain level

The human gastrointestinal (GI) tract harbors diverse microbes, and the family Lachnospiraceae is one of the most abundant and widely occurring bacterial groups in the human GI tract. Beneficial and adverse effects of the Lachnospiraceae on host health were reported, but the diversities at species/strain levels as well as their metabolites of Lachnospiraceae have been, so far, not well documented. In the present study, we report on the collection of 77 human-originated Lachnospiraceae species (please refer hLchsp, https://hgmb.nmdc.cn/subject/lachnospiraceae) and the in vitro metabolite profiles of 110 Lachnospiraceae strains (https://hgmb.nmdc.cn/subject/lachnospiraceae/metabolites). The Lachnospiraceae strains in hLchsp produced 242 metabolites of 17 categories. The larger categories were alcohols (89), ketones (35), pyrazines (29), short (C2-C5), and long (C > 5) chain acids (31), phenols (14), aldehydes (14), and other 30 compounds. Among them, 22 metabolites were aromatic compounds. The well-known beneficial gut microbial metabolite, butyric acid, was generally produced by many Lachnospiraceae strains, and Agathobacter rectalis strain Lach-101 and Coprococcus comes strain NSJ-173 were the top 2 butyric acid producers, as 331.5 and 310.9 mg/L of butyric acids were produced in vitro, respectively. Further analysis of the publicly available cohort-based volatile-metabolomic data sets of human feces revealed that over 30% of the prevailing volatile metabolites were covered by Lachnospiraceae metabolites identified in this study. This study provides Lachnospiraceae strain resources together with their metabolic profiles for future studies on host-microbe interactions and developments of novel probiotics or biotherapies.

Hydrogen Ion Dynamics as the Fundamental Link between Neurodegenerative Diseases and Cancer: Its Application to the Therapeutics of Neurodegenerative Diseases with Special Emphasis on Multiple Sclerosis

The pH-related metabolic paradigm has rapidly grown in cancer research and treatment. In this contribution, this recent oncological perspective has been laterally assessed for the first time in order to integrate neurodegeneration within the energetics of the cancer acid-base conceptual frame. At all levels of study (molecular, biochemical, metabolic, and clinical), the intimate nature of both processes appears to consist of opposite mechanisms occurring at the far ends of a physiopathological intracellular pH/extracellular pH (pHi/pHe) spectrum. This wide-ranging original approach now permits an increase in our understanding of these opposite processes, cancer and neurodegeneration, and, as a consequence, allows us to propose new avenues of treatment based upon the intracellular and microenvironmental hydrogen ion dynamics regulating and deregulating the biochemistry and metabolism of both cancer and neural cells. Under the same perspective, the etiopathogenesis and special characteristics of multiple sclerosis (MS) is an excellent model for the study of neurodegenerative diseases and, utilizing this pioneering approach, we find that MS appears to be a metabolic disease even before an autoimmune one. Furthermore, within this paradigm, several important aspects of MS, from mitochondrial failure to microbiota functional abnormalities, are analyzed in depth. Finally, and for the first time, a new and integrated model of treatment for MS can now be advanced.

Microbiome Methods in Experimental Autoimmune Encephalomyelitis

Microbiome composition studies are increasingly shedding light on animal models of disease. This paper describes a protocol for analyzing the gut microbiome composition prior to and after the induction of mice to experimental autoimmune encephalomyelitis (EAE), the principal animal model of the human neuroinflammatory demyelinating disease multiple sclerosis (MS). We also address and provide data assessing the impact of mice reared in different animal facilities on EAE induction. Furthermore, we discuss potential regulators of the gut-microbiome-brain axis (GMBA) in relation to neuroinflammation and implications on demyelinating disease states. Our results suggest that mice reared in different animal facilities produce different levels of EAE induction. These results highlight the importance of accounting for consistent environmental conditions when inducing EAE and other animal models of disease. © 2021 Wiley Periodicals LLC. Basic Protocol 1: Study of the composition of the gut microbiome in the neuroinflammatory model of experimental autoimmune encephalomyelitis Basic Protocol 2: Experimental procedures for DNA extraction and microbiome analysis.

Farnesol Ameliorates Demyelinating Phenotype in a Cellular and Animal Model of Charcot-Marie-Tooth Disease Type 1A

Charcot-Marie-Tooth disease (CMT) is a genetically heterogeneous disease affecting the peripheral nervous system that is caused by either the demyelination of Schwann cells or degeneration of the peripheral axon. Currently, there are no treatment options to improve the degeneration of peripheral nerves in CMT patients. In this research, we assessed the potency of farnesol for improving the demyelinating phenotype using an animal model of CMT type 1A. In vitro treatment with farnesol facilitated myelin gene expression and ameliorated the myelination defect caused by PMP22 overexpression, the major causative gene in CMT. In vivo administration of farnesol enhanced the peripheral neuropathic phenotype, as shown by rotarod performance in a mouse model of CMT1A. Electrophysiologically, farnesol-administered CMT1A mice exhibited increased motor nerve conduction velocity and compound muscle action potential compared with control mice. The number and diameter of myelinated axons were also increased by farnesol treatment. The expression level of myelin protein zero (MPZ) was increased, while that of the demyelination marker, neural cell adhesion molecule (NCAM), was reduced by farnesol administration. These data imply that farnesol is efficacious in ameliorating the demyelinating phenotype of CMT, and further elucidation of the underlying mechanisms of farnesol’s effect on myelination might provide a potent therapeutic strategy for the demyelinating type of CMT.

Waiting for PARIS-A Biological Target in Search of a Drug

A recent breakthrough paper published in Science Translational Medicine has provided compelling evidence that inhibition of Parkin Interacting Substrate (PARIS) may offer clinical researchers an important new therapeutic approach since it shows considerable promise as an important biological target potentially capable of pharmaceutical intervention to slow long term neurodegeneration in patients with Parkinson’s disease (PD). We present several PD-relevant perspectives on this paper that were not discussed in that otherwise entirely scientific narrative. We also outline the some of the work leading up to it, including the massive drug screen that proved necessary to discover a clinically suitable inhibitor of PARIS (Farnesol), as well as relevant PD research within the wider drug class, issues surrounding its future formulation, and next steps in translating this new knowledge into the clinic to evaluate possible long-term PD patient benefits.