The Therapeutic Effect of Phosphopeptide P140 Attenuates Inflammation Induced by Uric Acid Crystals in Gout Arthritis Mouse Model

Disruption of survivin protein expression by treatment with YM155 accelerates the resolution of neutrophilic inflammation

BACKGROUND AND PURPOSE

Prolonged survival of neutrophils is essential for determining the progression and severity of inflammatory and immune-mediated disorders, including gouty arthritis. Survivin, an anti-apoptotic molecule, has been described as a regulator of cell survival. This study aims to examine the effects of YM155 treatment, a survivin selective suppressant, in maintaining neutrophil survival in vitro and in vivo experimental settings of neutrophilic inflammation.

EXPERIMENTAL APPROACH

BALB/c mice were injected with monosodium urate (MSU) crystals and treated with YM155 (intra-articularly) at the peak of inflammatory response. Leukocyte recruitment, apoptosis neutrophil and efferocytosis were determined by knee joint wash cell morphology counting and flow cytometry. Resolution interval (Ri) was quantified by neutrophil infiltration, monitoring the amplitude and duration of the inflammation. Cytokine production was measured by ELISA. Mechanical hypernociception was assessed using an electronic von Frey aesthesiometer. Efferocytosis was evaluated in zymosan-induced neutrophilic peritonitis. Survivin and cleaved caspase-3 expression was determined in human neutrophils by flow cytometry.

KEY RESULTS

Survivin was expressed in neutrophils during MSU-induced gout, and the treatment with YM155 reduced survivin expression and shortened Ri from ∼8 h observed in vehicle-treated mice to ∼5.5 h, effect accompanied by increased neutrophil apoptosis and efferocytosis, both crucial for the inflammation resolution. Reduced IL-1β and CXCL1 levels were also observed in periarticular tissue. YM155 reduced histopathological score and hypernociceptive response. In human neutrophils, lipopolysaccharide (LPS) increased survivin expression, whereas survivin inhibition with YM155 induced neutrophil apoptosis, with activation of caspase-3.

CONCLUSIONS AND IMPLICATIONS

Survivin may be a promising therapeutic target to control neutrophilic inflammation.

Inclusion body myositis: Correcting impaired mitochondrial and lysosomal autophagy as a potential therapeutic strategy

Inclusion body myositis (IBM) is a late onset sporadic myopathy with a characteristic clinical presentation, but as yet unknown aetiology or effective treatment. Typical clinical features are early predominant asymmetric weakness of finger flexor and knee extensor muscles. Muscle biopsy shows endomysial inflammatory infiltrate, mitochondrial changes, and protein aggregation. Proteostasis (protein turnover) appears to be impaired, linked to potentially dysregulated chaperone-mediated autophagy and mitophagy (a type of mitochondrial quality control). In this review, we bring together the most recent clinical and biological data describing IBM. We then address the question of diagnosing this pathology and the relevance of the current biological markers that characterize IBM. In these descriptions, we put a particular emphasis on data related to the deregulation of autophagic processes and to the mitochondrial-lysosomal crosstalk. Finally, after a short description of current treatments, an overview is provided pointing towards novel therapeutic targets and emerging regulatory molecules that are being explored for treating IBM. Special attention is paid to autophagy inhibitors that may offer innovative breakthrough therapies for patients with IBM.

Hetero-Diels-Alder and CuAAC Click Reactions for Fluorine-18 Labeling of Peptides: Automation and Comparative Study of the Two Methods

Radiolabeled peptides are valuable tools for diagnosis or therapies; they are often radiofluorinated using an indirect approach based on an F-18 prosthetic group. Herein, we are reporting our results on the F-18 radiolabeling of three peptides using two different methods based on click reactions. The first one used the well-known CuAAC reaction, and the second one is based on our recently reported hetero-Diels-Alder (HDA) using a dithioesters (thia-Diels-Alder) reaction. Both methods have been automated, and the 18F-peptides were obtained in similar yields and synthesis time (37-39% decay corrected yields by both methods in 120-140 min). However, to obtain similar yields, the CuAAC needs a large amount of copper along with many additives, while the HDA is a catalyst and metal-free reaction necessitating only an appropriate ratio of water/ethanol. The HDA can therefore be considered as a minimalist method offering easy access to fluorine-18 labeled peptides and making it a valuable additional tool for the indirect and site-specific labeling of peptides or biomolecules.

Pharmacological targets at the lysosomal autophagy-NLRP3 inflammasome crossroads

Many aspects of cell homeostasis and integrity are maintained by the nucleotide-binding oligomerization domain (NOD)-like receptor (NLR) family pyrin domain-containing 3 (NLRP3) inflammasome. The NLRP3 oligomeric protein complex assembles in response to exogenous and endogenous danger signals. This inflammasome has also been implicated in the pathogenesis of a range of disease conditions, particularly chronic inflammatory diseases. Given that NLRP3 modulates autophagy, which is also a key regulator of inflammasome activity, excessive inflammation may be controlled by targeting this intersecting pathway. However, specific niche areas of NLRP3-autophagy interactions and their reciprocal regulatory mechanisms remain underexplored. Consequently, we lack treatment methods specifically targeting this pivotal axis. Here, we discuss the potential of such strategies in the context of autoimmune and metabolic diseases and propose some research avenues.

The abscopal effect: Implications for drug discovery in autoimmunity

The emergence of novel targeted therapies and the tools that increase the stability and delivery of drugs have greatly improved treatment outcomes in autoimmune diseases (ADs). Recently-developed strategies deplete specific deleterious T- and B-cell subsets, interrupt receptor-ligand interactions, and/or inhibit the secretion or activity of inflammatory mediators linked to tissue damage. Although generally efficient, these lines of intervention have limitations, with documented cases of drug-resistance and undesired side effects. They are also difficult to apply to non-organ-specific ADs, where the trigger and effector antigens are unknown and in which autoimmune activity is widely spread throughout the body. The potential of cellular modulators that act at a distance from the affected site, by abscopal effect, as described in the case of cancer radio- and immuno-therapy might be especially efficient in the context of ADs. Future research to discover small molecule- and peptide-based treatments will need to explore potential drugs with abscopal effects that could elicit potent immune tolerance and clinical quiescence to restore quality of life of affected patients.

The role of lysosomes in metabolic and autoimmune diseases

Lysosomes are catabolic organelles that contribute to the degradation of intracellular constituents through autophagy and of extracellular components through endocytosis, phagocytosis and macropinocytosis. They also have roles in secretory mechanisms, the generation of extracellular vesicles and certain cell death pathways. These functions make lysosomes central organelles in cell homeostasis, metabolic regulation and responses to environment changes including nutrient stresses, endoplasmic reticulum stress and defects in proteostasis. Lysosomes also have important roles in inflammation, antigen presentation and the maintenance of long-lived immune cells. Their functions are tightly regulated by transcriptional modulation via TFEB and TFE3, as well as by major signalling pathways that lead to activation of mTORC1 and mTORC2, lysosome motility and fusion with other compartments. Lysosome dysfunction and alterations in autophagy processes have been identified in a wide variety of diseases, including autoimmune, metabolic and kidney diseases. Deregulation of autophagy can contribute to inflammation, and lysosomal defects in immune cells and/or kidney cells have been reported in inflammatory and autoimmune pathologies with kidney involvement. Defects in lysosomal activity have also been identified in several pathologies with disturbances in proteostasis, including autoimmune and metabolic diseases such as Parkinson disease, diabetes mellitus and lysosomal storage diseases. Targeting lysosomes is therefore a potential therapeutic strategy to regulate inflammation and metabolism in a variety of pathologies.

Immunological and translational key challenges in systemic lupus erythematosus: A symposium update

The first LBMR-Tim (Toulouse Referral Medical Laboratory of Immunology) symposium convened on December 16, 2022 in Toulouse, France to address challenging questions in systemic lupus erythematosus (SLE). Special focus was put on (i) the role played by genes, sex, TLR7, and platelets on SLE pathophysiology; (ii) autoantibodies, urinary proteins, and thrombocytopenia contribution at the time of diagnosis and during follow-up; (iii) neuropsychiatric involvement, vaccine response in the COVID-19 era, and lupus nephritis management at the clinical frontline; and (iv) therapeutic perspectives in patients with lupus nephritis and the unexpected adventure of the Lupuzor/P140 peptide. The multidisciplinary panel of experts further supports the concept that a global approach including basic sciences, translational research, clinical expertise, and therapeutic development have to be prioritized in order to better understand and then improve the management of this complex syndrome.