Functional hypothalamic amenorrhea: gut microbiota composition and the effects of exogenous estrogen administration

Functional hypothalamic amenorrhea (FHA) is characterized by estrogen deficiency that significantly impacts metabolic, bone, cardiovascular, mental, and reproductive health. Given the importance of environmental factors such as stress and body composition, and particularly considering the importance of estrogens in regulating the gut microbiota, some changes in the intestinal microenvironment are expected when all of these factors occur simultaneously. We aimed to assess whether the gut microbiota composition is altered in FHA and to determine the potential impact of hormonal replacement therapy (HRT) on the gut microbiota. This prospective observational study included 33 patients aged 18-34 yr with FHA and 10 age-matched healthy control women. Clinical, hormonal, and metabolic evaluations were performed at baseline for the FHA group only, whereas gut microbiota profile was assessed by 16S rRNA gene amplicon sequencing for both groups. All measurements were repeated in patients with FHA after receiving HRT for 6 mo. Gut microbiota alpha diversity at baseline was significantly different between patients with FHA and healthy controls (P < 0.01). At the phylum level, the relative abundance of Fusobacteria was higher in patients with FHA after HRT (P < 0.01), as was that of Ruminococcus and Eubacterium at the genus level (P < 0.05), which correlated with a decrease in circulating proinflammatory cytokines. FHA is a multidimensional disorder that is interconnected with dysbiosis through various mechanisms, particularly involving the gut-brain axis. HRT appears to induce a favorable shift in the gut microbiota in patients with FHA, which is also associated with a reduction in the systemic inflammatory status.NEW & NOTEWORTHY Our study marks the first comprehensive analysis of gut microbiota composition in FHA and the impact of HRT on it, along with biochemical, anthropometric, and psychometric aspects. Our results indicate distinct gut microbiota composition in patients with FHA compared with healthy individuals. Importantly, HRT prompts a transition toward a more beneficial gut microbiota profile and reduced inflammation. This study validates the concept of FHA as a multifaceted disorder interlinked with dysbiosis, particularly involving the gut-brain axis.

Treatment of HCC with claudin-1-specific antibodies suppresses carcinogenic signaling and reprograms the tumor microenvironment

BACKGROUND & AIMS

Despite recent approvals, the response to treatment and prognosis of patients with advanced hepatocellular carcinoma (HCC) remain poor. Claudin-1 (CLDN1) is a membrane protein that is expressed at tight junctions, but it can also be exposed non-junctionally, such as on the basolateral membrane of the human hepatocyte. While CLDN1 within tight junctions is well characterized, the role of non-junctional CLDN1 and its role as a therapeutic target in HCC remains unexplored.

METHODS

Using humanized monoclonal antibodies (mAbs) specifically targeting the extracellular loop of human non-junctional CLDN1 and a large series of patient-derived cell-based and animal model systems we aimed to investigate the role of CLDN1 as a therapeutic target for HCC.

RESULTS

Targeting non-junctional CLDN1 markedly suppressed tumor growth and invasion in cell line-based models of HCC and patient-derived 3D ex vivo models. Moreover, the robust effect on tumor growth was confirmed in vivo in a large series of cell line-derived xenograft and patient-derived xenograft mouse models. Mechanistic studies, including single-cell RNA sequencing of multicellular patient HCC tumorspheres, suggested that CLDN1 regulates tumor stemness, metabolism, oncogenic signaling and perturbs the tumor immune microenvironment.

CONCLUSIONS

Our results provide the rationale for targeting CLDN1 in HCC and pave the way for the clinical development of CLDN1-specific mAbs for the treatment of advanced HCC.

IMPACT AND IMPLICATIONS

Hepatocellular carcinoma (HCC) is associated with high mortality and unsatisfactory treatment options. Herein, we identified the cell surface protein Claudin-1 as a treatment target for advanced HCC. Monoclonal antibodies targeting Claudin-1 inhibit tumor growth in patient-derived ex vivo and in vivo models by modulating signaling, cell stemness and the tumor immune microenvironment. Given the differentiated mechanism of action, the identification of Claudin-1 as a novel therapeutic target for HCC provides an opportunity to break the plateau of limited treatment response. The results of this preclinical study pave the way for the clinical development of Claudin-1-specific antibodies for the treatment of advanced HCC. It is therefore of key impact for physicians, scientists and drug developers in the field of liver cancer and gastrointestinal oncology.

A monoclonal antibody targeting nonjunctional claudin-1 inhibits fibrosis in patient-derived models by modulating cell plasticity

Tissue fibrosis is a key driver of end-stage organ failure and cancer, overall accounting for up to 45% of deaths in developed countries. There is a large unmet medical need for antifibrotic therapies. Claudin-1 (CLDN1) is a member of the tight junction protein family. Although the role of CLDN1 incorporated in tight junctions is well established, the function of nonjunctional CLDN1 (njCLDN1) is largely unknown. Using highly specific monoclonal antibodies targeting a conformation-dependent epitope of exposed njCLDN1, we show in patient-derived liver three-dimensional fibrosis and human liver chimeric mouse models that CLDN1 is a mediator and target for liver fibrosis. Targeting CLDN1 reverted inflammation-induced hepatocyte profibrogenic signaling and cell fate and suppressed the myofibroblast differentiation of hepatic stellate cells. Safety studies of a fully humanized antibody in nonhuman primates did not reveal any serious adverse events even at high steady-state concentrations. Our results provide preclinical proof of concept for CLDN1-specific monoclonal antibodies for the treatment of advanced liver fibrosis and cancer prevention. Antifibrotic effects in lung and kidney fibrosis models further indicate a role of CLDN1 as a therapeutic target for tissue fibrosis across organs. In conclusion, our data pave the way for further therapeutic exploration of CLDN1-targeting therapies for fibrotic diseases in patients.

Hepatocellular carcinoma chemoprevention by targeting the angiotensin-converting enzyme and EGFR transactivation

Hepatocellular carcinoma (HCC) is a leading cause of death among cirrhotic patients, for which chemopreventive strategies are lacking. Recently, we developed a simple human cell-based system modeling a clinical prognostic liver signature (PLS) predicting liver disease progression and HCC risk. In a previous study, we applied our cell-based system for drug discovery and identified captopril, an approved angiotensin converting enzyme (ACE) inhibitor, as a candidate compound for HCC chemoprevention. Here, we explored ACE as a therapeutic target for HCC chemoprevention. Captopril reduced liver fibrosis and effectively prevented liver disease progression toward HCC development in a diethylnitrosamine (DEN) rat cirrhosis model and a diet-based rat model for nonalcoholic steatohepatitis–induced (NASH-induced) hepatocarcinogenesis. RNA-Seq analysis of cirrhotic rat liver tissues uncovered that captopril suppressed the expression of pathways mediating fibrogenesis, inflammation, and carcinogenesis, including epidermal growth factor receptor (EGFR) signaling. Mechanistic data in liver disease models uncovered a cross-activation of the EGFR pathway by angiotensin. Corroborating the clinical translatability of the approach, captopril significantly reversed the HCC high-risk status of the PLS in liver tissues of patients with advanced fibrosis. Captopril effectively prevents fibrotic liver disease progression toward HCC development in preclinical models and is a generic and safe candidate drug for HCC chemoprevention.

Abstract P153: Claudin-1 is a therapeutic target for hepatocellular carcinoma

Introduction: Hepatocellular carcinoma (HCC) is the fastest rising and fourth leading cause of cancer death worldwide. While new therapeutic modalities have been recently approved, treatment response and survival in patients remain poor. Claudin-1 (CLDN1) is a cell membrane protein mediating cell-cell adhesion, fate and differentiation. While the function of CLDN1 within tight junctions is well characterized, the role of non-junctional CLDN1 in HCC remains unexplored. Aim and methods: Using humanized monoclonal antibodies (mAbs) targeting specifically the extracellular loop of human non-junctional CLDN1 and a large series of patient-derived cell-based and animal model systems we aimed to investigate the role of CLDN1 as therapeutic target for treatment of HCC. Results: Targeting non-junctional CLDN1 robustly suppressed tumor growth in a large series of patient-derived model systems, including multicellular tumorspheres and patient-derived xenograft (PDX) mouse models. In vivo and ex vivo studies further suggested synergistic efficacy in combination with sorafenib. Mechanistic studies revealed that CLDN1 mAbs suppressed tumor cell proliferation, invasion and stemness by interfering with Src, Wnt-β-catenin and STAT3 signaling. Treatment with humanized anti-CLDN1 mAbs is considered to be safe, as administration in non-human primates and mouse models did not reveal any major toxicity even when high doses largely exceeding the therapeutic need were repeatedly applied. Conclusion: Our results provide robust pre-clinical proof-of-concept for humanized CLDN1-specific mAbs for treatment of HCC. The unique and differentiated mechanism of action has the potential to break the plateau of limited response and survival offered by currently approved therapies.

Citation Format: Natascha Roehlen, Marion Muller, Sara Cherradi, Frank Juehling, Francois H.T. Duong, Nuno Almeida, Fabio Del Zompo, Mirian Fernandez, Tobias Riedl, Hussein El Saghire, Antonio Saviano, Sarah Durand, Clara Ponsolles, Marine Oudot, Emanuele Felli, Patrick Pessaux, Irwin Davidson, Emilie Crouchet, Patrick Laquerriere, Mathias Heikenwälder, Roberto Iacone, Markus Meyer, Greg Elson, Tamas Schweighoffer, Catherine Schuster, Laurent Mailly, Joachim Lupberger, Thomas F Baumert. Claudin-1 is a therapeutic target for hepatocellular carcinoma [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2021 Oct 7-10. Philadelphia (PA): AACR; Mol Cancer Ther 2021;20(12 Suppl):Abstract nr P153.

Improved gut microbiota features after the resolution of SARS‑CoV‑2 infection

BACKGROUND

The severe acute respiratory syndrome coronavirus 2 (SARS‑CoV‑2) has a tropism for the gastrointestinal tract and several studies have shown an alteration of the gut microbiota in hospitalized infected patients. However, long-term data on microbiota changes after recovery are lacking.

METHODS

We enrolled 30 patients hospitalized for SARS‑CoV‑2-related pneumonia. Their gut microbiota was analyzed within 48 h from the admission and compared with (1) that of other patients admitted for suspected bacterial pneumonia (control group) (2) that obtained from the same subject 6 months after nasopharyngeal swab negativization.

RESULTS

Gut microbiota alpha-diversity increased 6 months after the resolution of SARS-CoV-2 infection. Bacteroidetes relative abundance was higher (≈ 36.8%) in patients with SARS-CoV-2, and declined to 18.7% when SARS-CoV-2 infection resolved (p  =  0.004). Conversely, Firmicutes were prevalent (≈ 75%) in controls and in samples collected after SARS-CoV-2 infection resolution (p  =  0.001). Ruminococcaceae, Lachnospiraceae and Blautia increased after SARS-CoV-2 infection resolution, rebalancing the gut microbiota composition.

CONCLUSION

SARS-CoV-2 infection is associated with changes in the gut microbiome, which tend to be reversed in long-term period.

Liver involvement is not associated with mortality: results from a large cohort of SARS-CoV-2-positive patients

BACKGROUND

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is frequently associated with liver test abnormalities.

AIMS

To describe the evolution of liver involvement during SARS-CoV-2 infection and its effect on clinical course and mortality.

METHODS

Data of 515 SARS-CoV-2-positive patients were collected at baseline and during follow-up, last evaluation or death. Stratification based on need for hospitalisation, severe disease and admission to intensive care unit (ICU) was performed. The association between liver test abnormalities (baseline and peak values) and ICU admission or death was also explored.

RESULTS

Liver test abnormalities were found in 161 (31.3%) patients. Aspartate aminotransferase (AST), alanine aminotransferase (ALT) and gamma glutamyl transferase (GGT) were increased in 20.4%, 19% and 13.6% of patients, respectively. Baseline liver test abnormalities were associated with increased risk of ICU admission (OR 2.19 [95% CI 1.24-3.89], P = 0.007) but not with mortality (OR 0.84 [95% CI 0.49-1.41], P = 0.51). Alkaline phosphatase (ALP) peak values were correlated with risk of death (OR 1.007 [95% CI 1.002-1.01], P = 0.005) along with age, multiple comorbidities, acute respiratory distress syndrome, ICU admission and C-reactive protein. Alterations of liver tests worsened within 15 days of hospitalisation; however, in patients with the longest median follow-up, the prevalence of liver test alterations decreased over time, returning to around baseline levels.

CONCLUSIONS

In SARS-CoV-2-positive patients without pre-existing severe chronic liver disease, baseline liver test abnormalities are associated with the risk of ICU admission and tend to normalise over time. The ALP peak value may be predictive of a worse prognosis.

Microparticles Produced by Activated Platelets Carry a Potent and Functionally Active Angiogenic Signal in Subjects with Crohn's Disease

Microparticles (MPs) are submicron vesicles shed from various cell types upon activation, stimulation, and death. Activated platelets are an important source of circulating MPs in subjects with inflammatory diseases, including Crohn’s disease (CD). Angiogenesis is a hallmark of inflammation in CD and plays an active role in sustaining disease progression, while targeting angiogenesis may be an effective approach to block colitis. In this study, we analyzed the angiogenic content of the MPs produced by activated platelets in subjects with CD. We also evaluated whether the angiogenic signal carried by these MPs was functionally active, or able to induce angiogenesis. We found that, in subjects with CD, MPs produced by activated platelets contain significantly higher levels of angiogenic mRNAs, such as epidermal growth factor (EGF), platelet-derived growth factor-α (PDGFα), fibroblast growth factor (FGF-2), and angiopoietin-1 (ANGPT1), compared to MPs isolated from control subjects. They also contain significantly higher levels of prototypical angiogenic proteins, including vascular endothelial growth factor (VEGF), angiopoietin-1, endoglin, endothelin-1, pentraxin 3, platelet factor-4, plasminogen activator inhibitor-1 (PAI-1), tissue inhibitor of metalloproteinases-1 (TIMP-1), and thrombospondin 1. The protein content of these MPs is functionally active, since it has the ability to induce a robust angiogenic process in an endothelial cell/interstitial cell co-culture in vitro assay. Our results reveal a potential novel mechanism through which the angiogenic signal is delivered in subjects with CD, with potentially important clinical and therapeutic implications.

[The relationship between gut microbiota and cardiovascular diseases]

The prevalence of cardiometabolic disorders (obesity, type 2 diabetes and cardiovascular disorders) is increasing globally and is a leading cause of mortality worldwide. Both genetics and environmental factors are involved in the pathogenesis of these disorders. Recent studies have shown that a state of dysbiosis may be implicated in body weight control, insulin resistance and cardio-metabolic risk factors, but the underlying mechanisms remain to be fully understood. Here we describe the possible role of the gut microbiota in cardiovascular diseases.