Objective
Although oral methotrexate (MTX) remains the anchor drug for rheumatoid arthritis (RA), up to 50% of patients do not achieve a clinically adequate outcome. In addition, there is a lack of ...prognostic tools for treatment response prior to drug initiation. This study was undertaken to investigate whether interindividual differences in the human gut microbiome can aid in the prediction of MTX efficacy in new‐onset RA.
Methods
We performed 16S ribosomal RNA gene and shotgun metagenomic sequencing on the baseline gut microbiomes of drug‐naive patients with new‐onset RA (n = 26). Results were validated in an additional independent cohort (n = 21). To gain insight into potential microbial mechanisms, we conducted ex vivo experiments coupled with metabolomics analysis to evaluate the association between microbiome‐driven MTX depletion and clinical response.
Results
Our analysis revealed significant associations of the abundance of gut bacterial taxa and their genes with future clinical response (q < 0.05), including orthologs related to purine and MTX metabolism. Machine learning techniques were applied to the metagenomic data, resulting in a microbiome‐based model that predicted lack of response to MTX in an independent group of patients. Finally, MTX levels remaining after ex vivo incubation with distal gut samples from pretreatment RA patients significantly correlated with the magnitude of future clinical response, suggesting a possible direct effect of the gut microbiome on MTX metabolism and treatment outcomes.
Conclusion
Taken together, these findings are the first step toward predicting lack of response to oral MTX in patients with new‐onset RA and support the value of the gut microbiome as a possible prognostic tool and as a potential target in RA therapeutics.
Triple‐negative breast cancer (TNBC), an aggressive, metastatic and recurrent breast cancer (BC) subtype, currently suffers from a lack of adequately described spontaneously metastatic preclinical ...models that faithfully reproduce the clinical scenario. We describe two preclinical spontaneously metastatic TNBC orthotopic murine models for the development of advanced therapeutics: an immunodeficient human MDA‐MB‐231‐Luc model and an immunocompetent mouse 4T1 model. Furthermore, we provide a broad range of multifactorial analysis for both models that could provide relevant information for the development of new therapies and diagnostic tools. Our comparisons uncovered differential growth rates, stromal arrangements and metabolic profiles in primary tumors, and the presence of cancer‐associated adipocyte infiltration in the MDA‐MB‐231‐Luc model. Histopathological studies highlighted the more rapid metastatic spread to the lungs in the 4T1 model following a lymphatic route, while we observed both homogeneous (MDA‐MB‐231‐Luc) and heterogeneous (4T1) metastatic spread to axillary lymph nodes. We encountered unique metabolomic signatures in each model, including crucial amino acids and cell membrane components. Hematological analysis demonstrated severe leukemoid and lymphoid reactions in the 4T1 model with the partial reestablishment of immune responses in the immunocompromised MDA‐MB‐231‐Luc model. Additionally, we discovered β‐immunoglobulinemia and increased basal levels of G‐CSF correlating with a metastatic switch, with G‐CSF also promoting extramedullary hematopoiesis (both models) and causing hepatosplenomegaly (4T1 model). Overall, we believe that the characterization of these preclinical models will foster the development of advanced therapeutic strategies for TNBC treatment, especially for the treatment of patients presenting both, primary tumors and metastatic spread.
What's new?
Triple‐negative breast cancer (TNBC), an aggressive, metastatic, and recurrent breast cancer subtype, currently lacks adequately described spontaneously metastatic preclinical models that faithfully reproduce the clinical scenario. Here, the authors provide an in‐depth comparative analysis of two preclinical spontaneously metastatic TNBC orthotopic models, MDA‐MB‐231‐Luc and 4T1. The results reveal a metastatic switch in both models with immune system activation and serum‐protein profile reconfiguration, which may support resistance to treatment and recurrence in TNBC. The authors also identify critical functional biomarkers and metabolomic signatures for metastatic progression that may facilitate the development of anticancer therapeutics.
Background and Purpose
The integrated stress response (ISR) regulates translation in response to diverse stresses. ISR activation has been documented in amyotrophic lateral sclerosis (ALS) patients ...and ALS experimental models. In experimental models, both ISR stimulation and inhibition prevented ALS neurodegeneration; however, which mode of ISR regulation would work in patients is still debated. We previously demonstrated that the ISR modulator ISRIB (Integrated Stress Response InhiBitor, an eIF2B activator) enhances survival of neurons expressing the ALS neurotoxic allele SOD1 G93A. Here, we tested the effect of two ISRIB‐like eIF2B activators (2BAct and PRXS571) in the disease progression of transgenic SOD1G93A mice.
Experimental Approach
After biochemical characterization in primary neurons, SOD1G93A mice were treated with 2BAct and PRXS571. Muscle denervation of vulnerable motor units was monitored with a longitudinal electromyographic test. We used a clinical score to document disease onset and progression; force loss was determined with the hanging wire motor test. Motor neuronal survival was assessed by immunohistochemistry.
Key Results
In primary neurons, 2BAct and PRXS571 relieve the ISR‐imposed translational inhibition while maintaining high ATF4 levels. Electromyographic recordings evidenced an earlier and more dramatic muscle denervation in treated SOD1G93A mice that correlated with a decrease in motor neuron survival. Both compounds anticipated disease onset and shortened survival time.
Conclusion and Implications
2BAct and PRXS571 anticipate disease onset, aggravating muscle denervation and motor neuronal death of SOD1G93A mice. This study reveals that the ISR works as a neuroprotective pathway in ALS motor neurons and reveals the toxicity that eIF2B activators may display in ALS patients.
Background and Aims
Hepatocellular dedifferentiation is emerging as an important determinant in liver disease progression. Preservation of mature hepatocyte identity relies on a set of key genes, ...predominantly the transcription factor hepatocyte nuclear factor 4α (HNF4α) but also splicing factors like SLU7. How these factors interact and become dysregulated and the impact of their impairment in driving liver disease are not fully understood.
Approach and Results
Expression of SLU7 and that of the adult and oncofetal isoforms of HNF4α, driven by its promoter 1 (P1) and P2, respectively, was studied in diseased human and mouse livers. Hepatic function and damage response were analyzed in wild‐type and Slu7‐haploinsufficient/heterozygous (Slu7+/−) mice undergoing chronic (CCl4) and acute (acetaminophen) injury. SLU7 expression was restored in CCl4‐injured mice using SLU7‐expressing adeno‐associated viruses (AAV‐SLU7). The hepatocellular SLU7 interactome was characterized by mass spectrometry. Reduced SLU7 expression in human and mouse diseased livers correlated with a switch in HNF4α P1 to P2 usage. This response was reproduced in Slu7+/− mice, which displayed increased sensitivity to chronic and acute liver injury, enhanced oxidative stress, and marked impairment of hepatic functions. AAV‐SLU7 infection prevented liver injury and hepatocellular dedifferentiation. Mechanistically we demonstrate a unique role for SLU7 in the preservation of HNF4α1 protein stability through its capacity to protect the liver against oxidative stress. SLU7 is herein identified as a key component of the stress granule proteome, an essential part of the cell’s antioxidant machinery.
Conclusions
Our results place SLU7 at the highest level of hepatocellular identity control, identifying SLU7 as a link between stress‐protective mechanisms and liver differentiation. These findings emphasize the importance of the preservation of hepatic functions in the protection from liver injury.
Background
Despite the increasing incidence of anaphylaxis, its underlying molecular mechanisms and biomarkers for appropriate diagnosis remain undetermined. The rapid onset and potentially fatal ...outcome in the absence of managed treatment prevent its study. Up today, there are still no known biomarkers that allow an unequivocal diagnosis. Therefore, the aim of this study was to explore metabolic changes in patients suffering anaphylactic reactions depending on the trigger (food and/or drug) and severity (moderate and severe) in a real‐life set‐up.
Methods
Eighteen episodes of anaphylaxis, one per patient, were analysed. Sera were collected during the acute phase (T1), the recovery phase (T2) and around 2–3 months after the anaphylactic reaction (T0: basal state). Reactions were classified following an exhaustive allergological evaluation for severity and trigger. Sera samples were analysed using untargeted metabolomics combining liquid chromatography coupled to mass spectrometry (LC‐MS) and proton nuclear magnetic resonance spectroscopy (1H‐NMR).
Results
‘Food T1 vs T2’ and ‘moderate T1 vs T2’ anaphylaxis comparisons showed clear metabolic patterns during the onset of an anaphylactic reaction, which differed from those induced by drugs, food + drug or severe anaphylaxis. Moreover, the model of food anaphylaxis was able to distinguish the well‐characterized IgE (antibiotics) from non‐IgE‐mediated anaphylaxis (nonsteroidal anti‐inflammatory drugs), suggesting a differential metabolic pathway associated with the mechanism of action. Metabolic differences between ‘moderate vs severe’ at the acute phase T1 and at basal state T0 were studied. Among the altered metabolites, glucose, lipids, cortisol, betaine and oleamide were observed altered.
Conclusions
The results of this exploratory study provide the first evidence that different anaphylactic triggers or severity induce differential metabolic changes along time or at specific time‐point, respectively. Besides, the basal status T0 might identify high‐risk patients, thus opening new ways to understand, diagnose and treat anaphylaxis.
For the first time, the metabolic profile of anaphylaxis in a real‐life set‐up was characterized and provide evidence that different triggers (Food and Drug) and severity (Moderate and Severe) induce differential metabolic changes improving clinical practice. Eighteen episodes of anaphylaxis with a full clinical characterization were analyzed by metabolomics. The time points were: acute phase (T1), recovery phase (T2) and basal state (T0). Basal status might identify high risk patients, thus opening new ways to understand, diagnose and treat anaphylaxis
Multidrug-resistant organisms (MDRO) are a major threat to public health. MDRO infections, including those caused by vancomycin-resistant Enterococcus (VRE), frequently begin by colonization of the ...intestinal tract, a crucial step that is impaired by the intestinal microbiota. However, the specific members of the microbiota that suppress MDRO colonization and the mechanisms of such protection are largely unknown. Here, using metagenomics and mouse models that mimic the patients' exposure to antibiotics, we identified commensal bacteria associated with protection against VRE colonization. We further found a consortium of five strains that was sufficient to restrict VRE gut colonization in antibiotic treated mice. Transcriptomics in combination with targeted metabolomics and in vivo assays indicated that the bacterial consortium inhibits VRE growth through nutrient depletion, specifically by reducing the levels of fructose, a carbohydrate that boosts VRE growth in vivo. Finally, in vivo RNA-seq analysis of each strain of the consortium in combination with ex vivo and in vivo assays demonstrated that a single bacterium (Olsenella sp.) could recapitulate the effect of the consortium. Our results indicate that nutrient depletion by specific commensals can reduce VRE intestinal colonization, which represents a novel non-antibiotic based strategy to prevent infections caused by this multidrug-resistant organism.
To investigate whether urine metabolomic profile can be used to identify biomarkers associated to endometriosis.
Prospective study. For each subject, a urine sample was collected after overnight ...fasting and before surgery.
University medical center.
The clinical cohort included 45 endometriosis patients, diagnosed at early (n = 6) and advanced (n = 39) stages of the disease, and 36 healthy women. All women underwent diagnostic laparoscopy to visually confirm the presence or absence of endometriotic lesions.
Metabolomic profiling of urine samples based on (1)H-nuclear magnetic resonance (NMR) spectroscopy in combination with statistical approaches.
Comparative identification of metabolites present in urine from endometriosis patients and healthy women.
The urine metabolomic profile of endometriosis patients exhibited higher concentrations of N(1)-methyl-4-pyridone-5-carboxamide, guanidinosuccinate, creatinine, taurine, valine, and 2-hydroxyisovalerate and decreased concentrations of lysine compared with healthy women. Most of these metabolites are involved in inflammation and oxidative stress processes. These pathophysiologic events had been previously described to be present in ectopic endometrial proliferation foci.
Overall, the results demonstrate the potential of (1)H-NMR-based metabolomics, a rapid and noninvasive approach, to identify metabolic changes associated to endometriosis in urine samples. This information could be useful to get a better understanding of the pathogenesis of endometriosis, thus providing support to the noninvasive diagnosis of this pathology.
Abstract
Infections by multidrug-resistant
Enterobacteriaceae
(MRE) are life-threatening to patients. The intestinal microbiome protects against MRE colonization, but antibiotics cause collateral ...damage to commensals and open the way to colonization and subsequent infection. Despite the significance of this problem, the specific commensals and mechanisms that restrict MRE colonization remain largely unknown. Here, by performing a multi-omic prospective study of hospitalized patients combined with mice experiments, we find that
Lactobacillus
is key, though not sufficient, to restrict MRE gut colonization.
Lactobacillus rhamnosus
and
murinus
increase the levels of Clostridiales bacteria, which induces a hostile environment for MRE growth through increased butyrate levels and reduced nutrient sources. This mechanism of colonization resistance, an interaction between
Lactobacillus
spp. and Clostridiales involving cooperation between microbiota members, is conserved in mice and patients. These results stress the importance of exploiting microbiome interactions for developing effective probiotics that prevent infections in hospitalized patients.
Nearly 50% of human malignancies exhibit unregulated RAS-ERK signaling; inhibiting it is a valid strategy for antineoplastic intervention. Upon activation, ERK dimerize, which is essential for ERK ...extranuclear, but not for nuclear, signaling. Here, we describe a small molecule inhibitor for ERK dimerization that, without affecting ERK phosphorylation, forestalls tumorigenesis driven by RAS-ERK pathway oncogenes. This compound is unaffected by resistance mechanisms that hamper classical RAS-ERK pathway inhibitors. Thus, ERK dimerization inhibitors provide the proof of principle for two understudied concepts in cancer therapy: (1) the blockade of sub-localization-specific sub-signals, rather than total signals, as a means of impeding oncogenic RAS-ERK signaling and (2) targeting regulatory protein-protein interactions, rather than catalytic activities, as an approach for producing effective antitumor agents.
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•DEL-22379 inhibits ERK dimerization without affecting its phosphorylation.•DEL-22379 blocks proliferation of tumor cells harboring RAS-ERK pathway oncogenes.•In animal tumor models, DEL-22379 induces apoptosis, preventing tumor progression.•DEL-22379 is unaffected by resistance mechanisms that hamper BRAF/MEK inhibitors.
Herrero et al. identify a small molecule inhibitor of ERK dimerization that impedes the growth of tumor cells dependent on a hyperactivated RAS-ERK pathway. Importantly, the antitumor effect of this compound in cells is not affected by the reported resistance mechanisms for the current BRAF and MEK inhibitors.
To evaluate potential variations in the plasma metabolomic profile of endometriosis patients as a consequence of pathophysiologic alterations associated with this disorder.
Prospective study. For ...each subject, a plasma sample was collected after overnight fasting and before surgery.
University medical center.
The clinical cohort included 50 endometriosis patients, diagnosed at early (n = 6) and advanced (n = 44) stages of the disease, and 23 healthy women. All volunteers underwent diagnostic laparoscopy to visually confirm the presence or absence of endometriotic lesions.
Metabolomic profiling of plasma samples based on
H-nuclear magnetic resonance (NMR) spectroscopy in combination with statistical approaches.
Comparative identification of metabolites present in plasma from endometriosis patients and healthy women.
The plasma metabolomic profile of endometriosis patients was characterized by increased concentration of valine, fucose, choline-containing metabolites, lysine/arginine, and lipoproteins and decreased concentration of creatinine compared with healthy women. Metabolic alterations identified in the plasma metabolomic profile of endometriosis patients correlate with pathophysiologic events previously described in the progression of this disease.
The results highlight the potential of
H-NMR-based metabolomics to characterize metabolic alterations associated with endometriosis in plasma samples. This information could be useful to get a better understanding of the molecular mechanisms involved in the pathogenesis of endometriosis, thus facilitating the noninvasive diagnosis of this pathology at early stages.
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