From Bed to Bench and Back: TNF-α, IL-23/IL-17A, and JAK-Dependent Inflammation in the Pathogenesis of Psoriatic Synovitis

Psoriatic arthritis (PsA) is a chronic inflammatory immune-mediated disease with a burdensome impact on quality of life and substantial healthcare costs. To date, pharmacological interventions with different mechanisms of action, including conventional synthetic (cs), biological (b), and targeted synthetic (ts) disease-modifying antirheumatic drugs (DMARDs), have been proven efficacious, despite a relevant proportion of failures. The current approach in clinical practice and research is typically “predictive”: the expected response is based on stratification according to clinical, imaging, and laboratory data, with a “heuristic” approach based on “trial and error”. Several available therapeutic options target the TNF-α pathway, while others are directed against the IL-23/IL-17A axis. Janus kinase inhibitors (JAKis), instead, simultaneously block different pathways, endowing these drugs with a potentially “broad-spectrum” mechanism of action. It is not clear, however, whether targeting a specific pathway (e.g., TNF-α or the IL-23/IL-17 axis) could result in discordant effects over other approaches. In particular, in the case of “refractory to a treatment” patients, other pathways might be hyperactivated, with opposing, synergistic, or redundant biological significance. On the contrary, refractory states could be purely resistant to treatment as a whole. Since chronic synovitis is one of the primary targets of inflammation in PsA, synovial biomarkers could be useful in depicting specific biological characteristics of the inflammatory burden at the single-patient level, and despite not yet being implemented in clinical practice, these biomarkers might help in selecting the proper treatment. In this narrative review, we will provide an up-to-date overview of the knowledge in the field of psoriatic synovitis regarding studies investigating the relationships among different activated proinflammatory processes suitable for targeting by different available drugs. The final objective is to clarify the state of the art in the field of personalized medicine for psoriatic disease, aiming at moving beyond the current treatment schedules toward a patient-centered approach

LonP1 Differently Modulates Mitochondrial Function and Bioenergetics of Primary Versus Metastatic Colon Cancer Cells

Mitochondrial Lon protease (LonP1) is a multi-function enzyme that regulates mitochondrial functions in several human malignancies, including colorectal cancer (CRC). The mechanism(s) by which LonP1 contributes to colorectal carcinogenesis is not fully understood. We found that silencing LonP1 leads to severe mitochondrial impairment and apoptosis in colon cancer cells. Here, we investigate the role of LonP1 in mitochondrial functions, metabolism, and epithelial-mesenchymal transition (EMT) in colon tumor cells and in metastasis. LonP1 was almost absent in normal mucosa, gradually increased from aberrant crypt foci to adenoma, and was most abundant in CRC. Moreover, LonP1 was preferentially upregulated in colorectal samples with mutated p53 or nuclear \u3b2-catenin, and its overexpression led to increased levels of \u3b2-catenin and decreased levels of E-cadherin, key proteins in EMT, in vitro. LonP1 upregulation also induced opposite changes in oxidative phosphorylation, glycolysis, and pentose pathway in SW480 primary colon tumor cells when compared to SW620 metastatic colon cancer cells. In conclusion, basal LonP1 expression is essential for normal mitochondrial function, and increased LonP1 levels in SW480 and SW620 cells induce a metabolic shift toward glycolysis, leading to EMT

Calcium mishandling in absence of primary mitochondrial dysfunction drives cellular pathology in Wolfram Syndrome

Wolfram syndrome (WS) is a recessive multisystem disorder defined by the association of diabetes mellitus and optic atrophy, reminiscent of mitochondrial diseases. The role played by mitochondria remains elusive, with contradictory results on the occurrence of mitochondrial dysfunction. We evaluated 13 recessive WS patients by deep clinical phenotyping, including optical coherence tomography (OCT), serum lactic acid at rest and after standardized exercise, brain Magnetic Resonance Imaging, and brain and muscle Magnetic Resonance Spectroscopy (MRS). Finally, we investigated mitochondrial bioenergetics, network morphology, and calcium handling in patient-derived fibroblasts. Our results do not support a primary mitochondrial dysfunction in WS patients, as suggested by MRS studies, OCT pattern of retinal nerve fiber layer loss, and, in fibroblasts, by mitochondrial bioenergetics and network morphology results. However, we clearly found calcium mishandling between endoplasmic reticulum (ER) and mitochondria, which, under specific metabolic conditions of increased energy requirements and in selected tissue or cell types, may turn into a secondary mitochondrial dysfunction. Critically, we showed that Wolframin (WFS1) protein is enriched at mitochondrial-associated ER membranes and that in patient-derived fibroblasts WFS1 protein is completely absent. These findings support a loss-of-function pathogenic mechanism for missense mutations in WFS1, ultimately leading to defective calcium influx within mitochondria

Sertoli Cells as potential Pharmaceutical Carriers: uptake and stability

Sertoli cells (SC) have been used for their immunomodulatory properties in cell transplants (Emerich et al., 2003). Moreover, SC themselves may prevent immune rejection (Sipone et al., 2006) and possess a natural phagocytic activity: the latter may make them suitable as biocompatible drug delivery carriers. Porcine SC were loaded with PLA microspheres containing pharmaceutical agents (SC-MS). Phagocytosis was monitored over 24 hours; the uptake was measured by HPLC at fixed time points and followed up through 6 days. SC viability and morphology were monitored together with reactive oxygen species (ROS), DNA damage and parameters of SC functionality and immunomodulatory properties over time. A preliminary antibacterial activity was assessed in vitro. SC-MS were cryopreserved in liquid nitrogen and after plating underwent the same characterization. SC internalized drug loaded MS with an uptake rate of about 20% at 5 hours, that increased by 30% until day two. The uptake was stable up to 6 days with no differences in ROS, DNA damage, functional and immunomodulatory properties observed between control and loaded SC, even after cryopreservation/thawing. A spontaneous in vitro activity against pseudomonas strain, presented with SC alone, increased in presence of MS, and was maintained after cryoperservation. These results encourage further studies to understand the real potential of SC as drug delivery vehicles in trials in “in vivo” animal models

Transglutaminase 2 Contributes to Apoptosis Induction in Jurkat T Cells by Modulating Ca(2+) Homeostasis via Cross-Linking RAP1GDS1

BACKGROUND: Transglutaminase 2 (TG2) is a protein cross-linking enzyme known to be associated with the in vivo apoptosis program of T cells. However, its role in the T cell apoptosis program was not investigated yet. RESULTS: Here we report that timed overexpression of both the wild type (wt) and the cross-linking mutant of TG2 induced apoptosis in Jurkat T cells, the wt being more effective. Part of TG2 colocalised with mitochondria. WtTG2-induced apoptosis was characterized by enhanced mitochondrial Ca(2+) uptake. Ca(2+)-activated wtTG2 cross-linked RAP1, GTP-GDP dissociation stimulator 1, an unusual guanine exchange factor acting on various small GTPases, to induce a yet uncharacterized signaling pathway that was able to promote the Ca(2+) release from the endoplasmic reticulum via both Ins3P and ryanodine sensitive receptors leading to a consequently enhanced mitochondrial Ca(2+)uptake. CONCLUSIONS: Our data indicate that TG2 might act as a Ca(2+) sensor to amplify endoplasmic reticulum-derived Ca(2+) signals to enhance mitochondria Ca(2+) uptake. Since enhanced mitochondrial Ca(2+) levels were previously shown to sensitize mitochondria for various apoptotic signals, our data demonstrate a novel mechanism through which TG2 can contribute to the induction of apoptosis in certain cell types. Since, as compared to knock out cells, physiological levels of TG2 affected Ca(2+) signals in mouse embryonic fibroblasts similar to Jurkat cells, our data might indicate a more general role of TG2 in the regulation of mitochondrial Ca(2+) homeostasis

Mitophagy and mitochondrial balance.

Mitochondria are highly dynamic organelles, with a morphology ranging from small roundish elements to large interconnected networks. This fine architecture has a significant impact on mitochondrial homeostasis, and mitochondrial morphology is highly connected to specific cellular process. Autophagy is a catabolic process in which cell constituents, including proteins and organelles, are delivered to the lysosomal compartment for degradation. Autophagy has multiple physiological functions and recent advances have demonstrated that this process is linked to different human diseases, such as cancer and neurodegenerative disorders. In particular, it has been found that autophagy is a key determinant for the life span of mitochondria through a particularly fine-tuned mechanism called mitophagy, a selective form of autophagy, which ensures the preservation of healthy mitochondria through the removal of damaged or superfluous mitochondria. Mitophagy has been found to be altered in several pathologies and aberrant or excessive levels of this process are found in common human disorders. Thus, the measurement of the mitophagy levels is of fundamental relevance to elucidate the molecular mechanism of this process and, most importantly, its role in cellular homeostasis and disease. In this review, we will provide an overview of the current methods used to measure mitophagic levels, with particular emphasis on the techniques based on fluorescent probes

H-Ras-driven tumoral maintenance is sustained through caveolin-1-dependent alterations in calcium signaling.

A growing body of research has highlighted the complex range of tumoral traits acquired during H-Ras-driven transformation and maintenance, which include proliferative signaling, growth suppressor evasion and resistance to cell death. Clear molecular information about these processes is not yet available, but recent evidence has provided solid support for the importance of mitochondria. Here, we show that the induction of oncogenic H-Ras leads to changes in intracellular calcium (Ca2+), evaluate the temporal relationship between oncogene expression and mitochondrial physiology, and demonstrate that Ca2+ homeostasis is altered by caveolin-1, a protein that has a key role in tumor maintenance. Our results indicate that tumor-suppressor caveolin-1 is a core component of the Ca2+-dependent apoptotic pathway and participates in the regulation of critical mitochondrial functions during tumor development. The compromised caveolin-1/Ca2+ axis contributes to failure in both mitochondrial metabolism and apoptosis, thereby sustaining the neoplastic phenotype. These results illustrate a direct link between Ca2+ regulation and mitochondrial biology in cance