Selective ablation of Nfix in macrophages attenuates muscular dystrophy by inhibiting fibro-adipogenic progenitor-dependent fibrosis.

Muscular dystrophies are genetic diseases characterized by chronic inflammation and fibrosis. Macrophages are immune cells that sustain muscle regeneration upon acute injury but seem deleterious in the context of chronic muscle injury such as in muscular dystrophies. Here, we observed that the number of macrophages expressing the transcription factor Nfix increases in two distinct mouse models of muscular dystrophies. We showed that the deletion of Nfix in macrophages in dystrophic mice delays the establishment of fibrosis and muscle wasting, and increases grasp force. Macrophages lacking Nfix expressed more TNFα and less TGFß1, thus promoting apoptosis of fibro-adipogenic progenitors. Moreover, pharmacological treatment of dystrophic mice with a ROCK inhibitor accelerated fibrosis through the increase of Nfix expression by macrophages. Thus, we have identified Nfix as a macrophage profibrotic factor in muscular dystrophies, whose inhibition could be a therapeutic route to reduce severity of the dystrophic disease. © 2022 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Therapeutic approaches to preserve the musculature in Duchenne Muscular Dystrophy: The importance of the secondary therapies.

Muscular dystrophies (MDs) are heterogeneous diseases, characterized by primary wasting of skeletal muscle, which in severe cases, such as Duchenne Muscular Dystrophy (DMD), leads to wheelchair dependency, respiratory failure, and premature death. Research is ongoing to develop efficacious therapies, particularly for DMD. Most of the efforts, currently focusing on correcting or restoring the primary defect of MDs, are based on gene-addition, exon-skipping, stop codon read-through, and genome-editing. Although promising, most of them revealed several practical limitations. Shared knowledge in the field is that, in order to be really successful, any therapeutic approach has to rely on spared functional muscle tissue, restricting the number of patients eligible for clinical trials to the youngest and less compromised individuals. In line with this, many therapeutic strategies aim to preserve muscle tissue and function. This Review outlines the most interesting and recent studies addressing the secondary outcomes of DMD and how to better deliver the therapeutic agents. In the future, the effective treatment of DMD will likely require combinations of therapies addressing both the primary genetic defect and its consequences.

RhoA and ERK signalling regulate the expression of the transcription factor Nfix in myogenic cells.

The transcription factor Nfix belongs to the nuclear factor one family and has an essential role in prenatal skeletal muscle development, where it is a master regulator of the transition from embryonic to foetal myogenesis. Recently, Nfix was shown to be involved in adult muscle regeneration and in muscular dystrophies. Here, we have investigated the signalling that regulates Nfix expression, and show that JunB, a member of the AP-1 family, is an activator of Nfix, which then leads to foetal myogenesis. Moreover, we demonstrate that their expression is regulated through the RhoA/ROCK axis, which maintains embryonic myogenesis. Specifically, RhoA and ROCK repress ERK kinase activity, which promotes JunB and Nfix expression. Notably, the role of ERK in the activation of Nfix is conserved postnatally in satellite cells, which represent the canonical myogenic stem cells of adult muscle. As lack of Nfix in muscular dystrophies rescues the dystrophic phenotype, the identification of this pathway provides an opportunity to pharmacologically target Nfix in muscular dystrophies.

MEK-inhibitors decrease Nfix in muscular dystrophy but induce unexpected calcifications, partially rescued with Cyanidin diet.

Muscular dystrophies (MDs) are incurable genetic myopathies characterized by progressive degeneration of skeletal muscles. Dystrophic mice lacking the transcription factor Nfix display morphological and functional improvements of the disease. Recently, we demonstrated that MAPK signaling pathway positively regulates Nfix in muscle development and that Cyanidin, a natural antioxidant molecule, strongly ameliorates the pathology. To explore a synergistic approach aimed at treating MDs, we administered Trametinib, a clinically approved MEK inhibitor, alone or combined with Cyanidin to adult Sgca null mice. We observed that chronic treatment with Trametinib and Cyanidin reduced Nfix in myogenic cells but, unexpectedly, caused ectopic calcifications exclusively in dystrophic muscles. The combined treatment with Cyanidin resulted in histological improvements by preventing Trametinib-induced calcifications in Diaphragm and Soleus. Collectively, this first pilot study revealed that Nfix is modulated by the MAPK pathway in MDs, and that Cyanidin partly rescued the unexpected ectopic calcifications caused by MEK inhibition.

Nutritional intervention with cyanidin hinders the progression of muscular dystrophy.

Muscular Dystrophies are severe genetic diseases due to mutations in structural genes, characterized by progressive muscle wasting that compromises patients' mobility and respiratory functions. Literature underlined oxidative stress and inflammation as key drivers of these pathologies. Interestingly among different myofiber classes, type I fibers display a milder dystrophic phenotype showing increased oxidative metabolism. This work shows the benefits of a cyanidin-enriched diet, that promotes muscle fiber-type switch and reduced inflammation in dystrophic alpha-sarcoglyan (Sgca) null mice having, as a net outcome, morphological and functional rescue. Notably, this benefit is achieved also when the diet is administered in dystrophic animals when the signs of the disease are seriously evident. Our work provides compelling evidence that a cyanidin-rich diet strongly delays the progression of muscular dystrophies, paving the way for a combinatorial approach where nutritional-based reduction of muscle inflammation and oxidative stress facilitate the successful perspectives of definitive treatments.

Depression in patients with acute myocardial infarction: influence on autonomic nervous system and prognostic role. Results of a five-year follow-up study.

BACKGROUND: Although previous studies demonstrated an association between depressive symptoms and cardiac mortality after acute myocardial infarction (AMI) little is known about the possible mechanisms of this association. The aim of this study was to determine whether depressed patients present a cardiac autonomic dysfunction and whether this could represent the mediator of the influence of depression on their prognosis. METHODS: One hundred consecutive patients with AMI were recruited between January and December 1999. Major Depressive Disorder (MDD) was diagnosed by structured clinical interview and the presence of symptoms of depression was evaluated with self-administered Beck Depression Inventory (BDI). The influence of depression on autonomic nervous system was investigated measuring heart rate variability (HRV) and heart rate (HR) during 24-hour electrocardiographic monitoring. The end-points of the study were all-cause mortality, recurrent-AMI, revascularization and a composite end-point of all the previous. Potential confounders for depression status and events were entered into a multivariate regression model. RESULTS: Fifteen patients met the criteria for MDD and 35 patients showed mild-to-moderate symptoms of depression; women had a higher prevalence of depression than men (35% vs 9%; p<0.01). Depression was not related to the severity of ischaemic disease or to other clinical and demographic variables. Patients with MDD showed lower HRV (76+/-25 SD vs 99+/-33 SD ms; p<0.01) and higher HR (77+/-12 SD vs 68+/-9 SD bpm; p<0.01) than patients without MDD; moreover mild to moderate symptoms of depression (BDI score > or = 10) were associated with lower HRV (84+/-25 SD vs 102+/-35 SD ms; p=0.01) but not with significantly higher HR. After a mean follow-up of 60 months MDD was associated with an increase of all-cause mortality (OR 12; 95% CI 2.6-56; p<0.01) and of composite end-point (OR 2; 95% CI 1.2-3.6; p=0.01) but not with re-AMI and revascularization. In a simple regression model HRV values were predictors of mortality (p<0.01). However when added in the multiple regression model HRV did not have an independent correlation with the end-points considered and did not modify the correlation between depression and mortality. CONCLUSIONS: Patients with post-AMI depression have a cardiac autonomic dysfunction as reflected by decreased HRV and increased HR. This autonomic dysfunction seems not to be an independent mediator of the increased mortality observed in depressed patients during a 5-year follow-up.

Maxillofacial trauma and psychiatric sequelae: post-traumatic stress disorder.

Interest in the psychiatric consequences of trauma and the subsequent surgical intervention has been increasing steadily; therefore, the authors assessed the prevalence of acute symptoms of stress in patients who experienced a craniomaxillofacial injury. Fifty patients between the ages of 18 and 65 years were evaluated and assigned a score using the Injury Severity Scale (ISS). Within 48 hours of surgery (T0) and at 3 months after surgery (T1), the authors administered the Davidson Trauma Scale (DTS) to assess post-traumatic symptoms, Spielberger's State-Trait Anxiety Inventory (STAI) to assess symptoms of anxiety, and Zung's Self-rating Depression Scale (SDS) to assess depressive symptoms. Of the subjects, 44% (22 patients at T0) had acute symptoms of stress, and 26% (13 patients at T1) had post-traumatic stress symptoms. The statistical association between demographic variables was significant only for gender, especially for women. There was a significant correlation between the psychopathologic variables and trauma-specific symptoms at both T0 and T1; the same was true for the ISS at T0. Eight of the 13 patients with positive DTS results at 3 months had aesthetic and functional sequelae that might have served as reminders of the traumatic event. It is not only necessary to restitutio ad integrum the anatomy and function, but also to provide psychiatric support for patients experiencing psychiatric symptoms caused by traumatic events.