Resolvin D1 improves airway inflammation and exercise capacity in cystic fibrosis lung disease.

Mucus plugging and non-resolving inflammation are inherent features of cystic fibrosis (CF) that may lead to progressive lung disease and exercise intolerance, which are the main causes of morbidity and mortality for people with CF. Therefore, understanding the influence of mucus on basic mechanisms underlying the inflammatory response and identifying strategies to resolve mucus-driven airway inflammation and consequent morbidity in CF are of wide interest. Here, we investigated the effects of the proresolving lipid mediator resolvin (Rv) D1 on mucus-related inflammation as a proof-of-concept to alleviate the burden of lung disease and restore exercise intolerance in CF. We tested the effects of RvD1 on inflammatory responses of human organotypic airways and leukocytes to CF mucus and of humanized mice expressing the epithelial Na + channel (ßENaC-Tg) having CF-like mucus obstruction, lung disease, and physical exercise intolerance. RvD1 reduced pathogenic phenotypes of CF-airway supernatant (ASN)-stimulated human neutrophils, including loss of L-selectin shedding and CD16. RNASeq analysis identified select transcripts and pathways regulated by RvD1 in ASN-stimulated CF bronchial epithelial cells that are involved in sugar metabolism, NF-κB activation and inflammation, and response to stress. In in vivo inflammation using ßENaC TG mice, RvD1 reduced total leukocytes, PMN, and interstitial Siglec-MΦ when given at 6-8 weeks of age, and in older mice at 10-12 weeks of age, along with the decrease of pro-inflammatory chemokines and increase of anti-inflammatory IL-10. Furthermore, RvD1 treatment promoted the resolution of pulmonary exacerbation caused by Pseudomonas aeruginosa infection and significantly enhanced physical activity and energy expenditure associated with mucus obstruction, which was impaired in ßENaC-Tg mice compared with wild-type. These results demonstrate that RvD1 can rectify features of CF and offer proof-of-concept for its therapeutic application in this and other muco-obstructive lung diseases.

Resolvin D1 and D2 reduce SARS-CoV-2-induced inflammatory responses in cystic fibrosis macrophages.

An excessive, non-resolving inflammatory response underlies severe COVID-19 that may have fatal outcomes. Therefore, the investigation of endogenous pathways leading to resolution of inflammation is of interest to uncover strategies for mitigating inflammation in people with SARS-CoV-2 infection. This becomes particularly urgent in individuals with preexisting pathologies characterized by chronic respiratory inflammation and prone to bacterial infection, such as cystic fibrosis (CF). Here, we analyzed the immune responses to SARS-CoV-2 virion spike 1 glycoprotein (S1) of macrophages (MΦ) from volunteers with and without CF and tested the efficacy of resolvins (Rv) D1 and D2 in regulating the inflammatory and antimicrobial functions of MΦ exposed to S1. S1 significantly increased chemokine release, including interleukin (IL)-8, in CF and non-CF MΦ, while it enhanced IL-6 and tumor necrosis factor (TNF)-α in non-CF MΦ, but not in CF cells. S1 also triggered the biosynthesis of RvD1 and modulated microRNAs miR-16, miR-29a, and miR-103, known to control the inflammatory responses. RvD1 and RvD2 treatment abated S1-induced inflammatory responses in CF and non-CF MΦ, significantly reducing the release of select chemokines and cytokines including IL-8 and TNF-α. RvD1 and RvD2 both restored the expression of miR-16 and miR-29a, while selectively increasing miR-223 and miR-125a, which are involved in NF-κB activation and MΦ inflammatory polarization. During Pseudomonas aeruginosa infection, S1 stimulated the MΦ phagocytic activity that was further enhanced by RvD1 and RvD2. These results provide a map of molecular responses to SARS-CoV-2 in MΦ, key determinants of COVID-19-related inflammation, unveiling some peculiarity in the response of cells from individuals with CF. They also demonstrate beneficial, regulatory actions of RvD1 and RvD2 on SARS-CoV-2-induced inflammation.

Roles of Specialized Pro-Resolving Lipid Mediators in Autophagy and Inflammation.

Autophagy is a catabolic pathway that accounts for degradation and recycling of cellular components to extend cell survival under stress conditions. In addition to this prominent role, recent evidence indicates that autophagy is crucially involved in the regulation of the inflammatory response, a tightly controlled process aimed at clearing the inflammatory stimulus and restoring tissue homeostasis. To be efficient and beneficial to the host, inflammation should be controlled by a resolution program, since uncontrolled inflammation is the underlying cause of many pathologies. Resolution of inflammation is an active process mediated by a variety of mediators, including the so-called specialized pro-resolving lipid mediators (SPMs), a family of endogenous lipid autacoids known to regulate leukocyte infiltration and activities, and counterbalance cytokine production. Recently, regulation of autophagic mechanisms by these mediators has emerged, uncovering unappreciated connections between inflammation resolution and autophagy. Here, we summarize mechanisms of autophagy and resolution, focusing on the contribution of autophagy in sustaining paradigmatic examples of chronic inflammatory disorders. Then, we discuss the evidence that SPMs can restore dysregulated autophagy, hypothesizing that resolution of inflammation could represent an innovative approach to modulate autophagy and its impact on the inflammatory response.

Pyruvate prevents the development of age-dependent cognitive deficits in a mouse model of Alzheimer's disease without reducing amyloid and tau pathology.

Amyloid-ß (Aß) deposition and tau-dependent pathology are key features of Alzheimer's disease (AD). However, to date, approaches aimed at counteracting these two pathogenic factors have produced only modest therapeutic outcomes. More effective therapies should therefore consider additional pathogenic factors like energy production failure, hyperexcitability and excitotoxicity, oxidative stress, deregulation of metal ion homeostasis, and neuroinflammation. Pyruvate is an energy substrate associated with neuroprotective properties. In this study, we evaluated protective effects of long-term administration of pyruvate in 3xTg-AD mice, a preclinical AD model that develops amyloid-ß- and tau-dependent pathology. Chronic (9 months) treatment with pyruvate inhibited short and long-term memory deficits in 6 and 12 months old 3xTg-AD mice as assessed with the Morris water maze test. Pyruvate had no effects on intraneuronal amyloid-ß accumulation and, surprisingly, the molecule increased deposition of phosphorylated tau. Pyruvate did not change aerobic or anaerobic metabolisms but decreased lipid peroxidation, counteracted neuronal hyperexcitability, decreased baseline levels of oxidative stress, and also reduced reactive oxygen species-driven elevations of intraneuronal Zn(2+) as well as glutamate receptor-mediated deregulation of intraneuronal Ca(2+). Thus, pyruvate promotes beneficial cognitive effects without affecting Aß and tau pathology. The molecule mainly promotes a reduction of hyperexcitability, oxidative stress while favors the regulation of intraneuronal Ca(2+) and Zn(2+) homeostasis rather than acting as energy substrate. Pyruvate can be therefore a valuable, safe, and affordable pharmacological tool to be associated with classical anti-Aß and tau drugs to counteract the development and progression of AD-related cognitive deficits and neuronal loss.

Resolvin D1 reduces cancer growth stimulating a protective neutrophil-dependent recruitment of anti-tumor monocytes.

BACKGROUND: Innovative therapies to target tumor-associated neutrophils (PMN) are of clinical interest, since these cells are centrally involved in cancer inflammation and tumor progression. Resolvin D1 (RvD1) is a lipid autacoid that promotes resolution of inflammation by regulating the activity of distinct immune and non-immune cells. Here, using human papilloma virus (HPV) tumorigenesis as a model, we investigated whether RvD1 modulates PMN to reduce tumor progression. METHODS: Growth-curve assays with multiple cell lines and in vivo grafting of two distinct HPV-positive cells in syngeneic mice were used to determine if RvD1 reduced cancer growth. To investigate if and how RvD1 modulates PMN activities, RNA sequencing and multiplex cytokine ELISA of human PMN in co-culture with HPV-positive cells, coupled with pharmacological depletion of PMN in vivo, were performed. The mouse intratumoral immune cell composition was evaluated through FACS analysis. Growth-curve assays and in vivo pharmacological depletion were used to evaluate anti-tumor activities of human and mouse monocytes, respectively. Bioinformatic analysis of The Cancer Genome Atlas (TCGA) database was exploited to validate experimental findings in patients. RESULTS: RvD1 decreased in vitro and in vivo proliferation of human and mouse HPV-positive cancer cells through stimulation of PMN anti-tumor activities. In addition, RvD1 stimulated a PMN-dependent recruitment of classical monocytes as key determinant to reduce tumor growth in vivo. In human in vitro systems, exposure of PMN to RvD1 increased the production of the monocyte chemoattractant protein-1 (MCP-1), and enhanced transmigration of classical monocytes, with potent anti-tumor actions, toward HPV-positive cancer cells. Consistently, mining of immune cells infiltration levels in cervical cancer patients from the TCGA database evidenced an enhanced immune reaction and better clinical outcomes in patients with higher intratumoral monocytes as compared to patients with higher PMN infiltration. CONCLUSIONS: RvD1 reduces cancer growth by activating PMN anti-cancer activities and encouraging a protective PMN-dependent recruitment of anti-tumor monocytes. These findings demonstrate efficacy of RvD1 as an innovative therapeutic able to stimulate PMN reprogramming to an anti-cancer phenotype that restrains tumor growth.

Resolvin D1 Reduces Lung Infection and Inflammation Activating Resolution in Cystic Fibrosis.

Non-resolving lung inflammation and Pseudomonas aeruginosa infections are the underlying cause of morbidity and mortality in cystic fibrosis (CF). The endogenous lipid mediator resolvin (Rv) D1 is a potent regulator of resolution, and its roles, actions, and therapeutic potential in CF are of interest. Here, we investigated actions and efficacy of RvD1 in preclinical models of cystic fibrosis. Cftr knockout mice with chronic P. aeruginosa lung infection were treated with RvD1 to assess differences in lung bacterial load, inflammation, and tissue damage. Cells from volunteers with CF were treated with RvD1 during ex vivo infection with P. aeruginosa, and effects on phagocytosis and inflammatory signaling were determined. In CF mice, RvD1 reduced bacterial burden, neutrophil infiltration, and histological signs of lung pathology, improving clinical scores of diseases. Mechanistically, RvD1 increased macrophage-mediated bacterial and leukocyte clearance in vivo. The clinical significance of these findings is supported by actions in primary leukocytes and epithelial cells from volunteers with CF where RvD1 enhanced P. aeruginosa phagocytosis and reduced genes and proteins associated to NF-κB activation and leukocyte infiltration. Concentration of RvD1 in sputum from patients with CF was also inversely correlated to those of cytokines and chemokines involved in CF lung pathology. These findings demonstrate efficacy of RvD1 in enhancing resolution of lung inflammation and infections and provide proof of concept for its potential as a prototypic novel pro-resolutive therapeutic approach for CF.

Roles, Actions, and Therapeutic Potential of Specialized Pro-resolving Lipid Mediators for the Treatment of Inflammation in Cystic Fibrosis.

Non-resolving inflammation is the main mechanism of morbidity and mortality among patients suffering from cystic fibrosis (CF), the most common life-threatening human genetic disease. Resolution of inflammation is an active process timely controlled by endogenous specialized pro-resolving lipid mediators (SPMs) produced locally in inflammatory loci to restrain this innate response, prevent further damages to the host, and permit return to homeostasis. Lipoxins, resolvins, protectins, and maresins are SPM derived from polyunsaturated fatty acids that limit excessive leukocyte infiltration and pro-inflammatory signals, stimulate innate microbial killing, and enhance resolution. Their unique chemical structures, receptors, and bioactions are being elucidated. Accruing data indicate that SPMs carry protective functions against unrelenting inflammation and infections in preclinical models and human CF systems. Here, we reviewed their roles and actions in controlling resolution of inflammation, evidence for their impairment in CF, and proofs of principle for their exploitation as innovative, non-immunosuppressive drugs to address inflammation and infections in CF.

Effects of peptidyl-prolyl isomerase 1 depletion in animal models of prion diseases.

Pin1 is a peptidyl-prolyl isomerase that induces the cis-trans conversion of specific Ser/Thr-Pro peptide bonds in phosphorylated proteins, leading to conformational changes through which Pin1 regulates protein stability and activity. Since down-regulation of Pin1 has been described in several neurodegenerative disorders, including Alzheimer's Disease (AD), Parkinson's Disease (PD) and Huntington's Disease (HD), we investigated its potential role in prion diseases. Animals generated on wild-type (Pin1+/+), hemizygous (Pin1+/-) or knock-out (Pin1-/-) background for Pin1 were experimentally infected with RML prions. The study indicates that, neither the total depletion nor reduced levels of Pin1 significantly altered the clinical and neuropathological features of the disease.

α-Synuclein Amyloids Hijack Prion Protein to Gain Cell Entry, Facilitate Cell-to-Cell Spreading and Block Prion Replication.

The precise molecular mechanism of how misfolded α-synuclein (α-Syn) accumulates and spreads in synucleinopathies is still unknown. Here, we show the role of the cellular prion protein (PrPC) in mediating the uptake and the spread of recombinant α-Syn amyloids. The in vitro data revealed that the presence of PrPC fosters the higher uptake of α-Syn amyloid fibrils, which was also confirmed in vivo in wild type (Prnp +/+) compared to PrP knock-out (Prnp -/-) mice. Additionally, the presence of α-Syn amyloids blocked the replication of scrapie prions (PrPSc) in vitro and ex vivo, indicating a link between the two proteins. Indeed, whilst PrPC is mediating the internalization of α-Syn amyloids, PrPSc is not able to replicate in their presence. This observation has pathological relevance, since several reported case studies show that the accumulation of α-Syn amyloid deposits in Creutzfeldt-Jakob disease patients is accompanied by a longer disease course.

S-adenosylmethionine reduces the progress of the Alzheimer-like features induced by B-vitamin deficiency in mice.

Methylation reactions linked to homocysteine in the one-carbon metabolism are increasingly elicited in Alzheimer's disease, although the association of hyperhomocysteinemia and of low B vitamin levels with the disease is still debated. We previously demonstrated that hyperhomocysteinemia and DNA hypomethylation induced by B vitamin deficiency are associated with PSEN1 and BACE1 overexpression and amyloid production. The present study is aimed at assessing S-adenosylmethionine effects in mice kept under a condition of B vitamin deficiency. To this end, TgCRND8 mice and wild-type littermates were assigned to control or B vitamin deficient diet, with or without S-adenosylmethionine supplementation. We found that S-adenosylmethionine reduced amyloid production, increased spatial memory in TgCRND8 mice and inhibited the upregulation of B vitamin deficiency-induced PSEN1 and BACE1 expression and Tau phosphorylation in TgCRND8 and wild-type mice. Furthermore, S-adenosylmethionine treatment reduced plaque spreading independently on B vitamin deficiency. These results strengthen our previous observations on the possible role of one-carbon metabolism in Alzheimer's disease, highlighting hyperhomocysteinemia-related mechanisms in dementia onset/progression and encourage further studies aimed at evaluating the use of S-adenosylmethionine as a potential candidate drug for the treatment of the disease.