Mitochondrial Ca2+-dependent NLRP3 activation exacerbates the Pseudomonas aeruginosa-driven inflammatory response in cystic fibrosis

Mitochondrial and endoplasmic reticulum calcium homeostasis and cell death

The endoplasmic reticulum (ER) and mitochondria cannot be considered as static structures, as they intimately communicate, forming very dynamic platforms termed mitochondria-associated membranes (MAMs). In particular, the ER transmits proper Ca²⁺ signals to mitochondria, which decode them into specific inputs to regulate essential functions, including metabolism, energy production and apoptosis. Here, we will describe the different molecular players involved in the transfer of Ca²⁺ ions from the ER lumen to the mitochondrial matrix and how modifications in both ER-mitochondria contact sites and Ca²⁺ signaling can alter the cell death execution program.

Pharmaco-toxicological effects of the novel third-generation fluorinate synthetic cannabinoids, 5F-ADBINACA, AB-FUBINACA, and STS-135 in mice. In vitro and in vivo studies

INTRODUCTION

5F-ADBINACA, AB-FUBINACA, and STS-135 are 3 novel third-generation fluorinate synthetic cannabinoids that are illegally marketed as incense, herbal preparations, or research chemicals for their psychoactive cannabis-like effects.

METHODS

The present study aims at investigating the in vitro and in vivo pharmacological activity of 5F-ADBINACA, AB-FUBINACA, and STS-135 in male CD-1 mice, comparing their in vivo effects with those caused by the administration of Δ⁹ -THC and JWH-018. In vitro competition binding experiments revealed a nanomolar affinity and potency of the 5F-ADBINACA, AB-FUBINACA, and STS-135 on mouse and human CB₁ and CB₂ receptors. Moreover, these synthetic cannabinoids induced neurotoxicity in murine neuro-2a cells.

RESULTS

In vivo studies showed that 5F-ADBINACA, AB-FUBINACA, and STS-135 induced hypothermia; increased pain threshold to both noxious mechanical and thermal stimuli; caused catalepsy; reduced motor activity; impaired sensorimotor responses (visual, acoustic, and tactile); caused seizures, myoclonia, and hyperreflexia; and promoted aggressiveness in mice. Behavioral and neurological effects were fully prevented by the selective CB₁ receptor antagonist/inverse agonist AM 251. Differently, the visual sensory response induced by STS-135 was only partly prevented by the AM 251, suggesting a CB₁ -independent mechanism.

CONCLUSIONS

For the first time, the present study demonstrates the pharmaco-toxicological effects induced by the administration of 5F-ADBINACA, AB-FUBINACA, and STS-135 in mice and suggests their possible detrimental effects on human health.

Neutrophil pyroptosis mediates pathology of P. aeruginosa lung infection in the absence of the NADPH oxidase NOX2

Nod-like receptor family, CARD domain-containing 4 (NLRC4) inflammasome activation is required for efficient clearance of intracellular pathogens through caspsase-1-dependent pyroptosis in macrophages. Although neutrophils have a critical role in protection from Pseudomonas aeruginosa infection, the mechanisms regulating inflammasome-mediated pyroptosis in neutrophils and its physiological role are largely unknown. We sought to determine the specific mechanisms regulating neutrophil pyroptosis in P. aeruginosa strain PAO1 (PAO1) lung infection and to identify the pathological role of this process. Nox2^-/- models with reduced neutrophil antibacterial activity exhibited increased neutrophil pyroptosis, which was mediated by flagellin, a pathogenic PAO1 component. We also demonstrate that PAO1-induced pyroptosis depended on NLRC4 and Toll-like receptor 5 (TLR5) in neutrophils generated from Nlrc4^-/- or Tlr5^-/- mice. Our study reveals previously unknown mechanisms and physiological role of neutrophil pyroptosis during P. aeruginosa lung infection. Furthermore, our findings regarding neutrophil pyroptosis in the context of neutrophil dysfunction may explain the causes of acute and/or chronic infectious diseases discovered in immune-compromised patients.

Macrophages utilize the mitochondrial calcium uniporter for profibrotic polarization

Fibrosis in multiple organs, including the liver, kidney, and lung, often occurs secondary to environmental exposure. Asbestos exposure is one important environmental cause of lung fibrosis. The mechanisms that mediate fibrosis is not fully understood, although mitochondrial oxidative stress in alveolar macrophages is critical for fibrosis development. Mitochondrial Ca²⁺ levels can be associated with production of reactive oxygen species. Here, we show that patients with asbestosis have higher levels of mitochondrial Ca²⁺ compared with normal patients. The mitochondrial calcium uniporter (MCU) is a highly selective ion channel that transports Ca²⁺ into the mitochondrial matrix to modulate metabolism. Asbestos exposure increased mitochondrial Ca²⁺ influx in alveolar macrophages from wild-type, but not MCU^+/-, mice. MCU expression polarized macrophages to a profibrotic phenotype after exposure to asbestos, and the profibrotic polarization was regulated by MCU-mediated ATP production. Profibrotic polarization was abrogated when MCU was absent or its activity was blocked. Of more importance, mice that were deficient in MCU were protected from pulmonary fibrosis. Regulation of mitochondrial Ca²⁺ suggests that MCU may play a pivotal role in the development of fibrosis and could potentially be a therapeutic target for pulmonary fibrosis.-Gu, L., Larson-Casey, J. L., Carter, A. B. Macrophages utilize the mitochondrial calcium uniporter for profibrotic polarization.

Bacterial Secretant from Pseudomonas aeruginosa Dampens Inflammasome Activation in a Quorum Sensing-Dependent Manner

Inflammasome signaling can contribute to host innate immune defense against bacterial pathogens such as Pseudomonas aeruginosa. However, bacterial evasion of host inflammasome activation is still poorly elucidated. Quorum sensing (QS) is a bacterial communication mechanism that promotes coordinated adaptation by triggering expression of a wide range of genes. QS is thought to strongly contribute to the virulence of P. aeruginosa, but the molecular impact of bacterial QS on host inflammasome defense is completely unknown. Here, we present evidence that QS-related factors of the bacterial secretant (BS) from P. aeruginosa can dampen host inflammasome signaling in mouse bone marrow-derived macrophages. We found that BS from QS-defective ΔlasR/rhlR mutant, but not from wild-type (WT) P. aeruginosa, induces robust activation of the NLRC4 inflammasome. P. aeruginosa-released flagellin mediates this inflammasome activation by ΔlasR/rhlR secretant, but QS-regulated bacterial proteases in the WT BS impair extracellular flagellin to attenuate NLRC4 inflammasome activation. P. aeruginosa-secreted proteases also degrade inflammasome components in the extracellular space to inhibit the propagation of inflammasome-mediated responses. Furthermore, QS-regulated virulence factor pyocyanin and QS autoinducer 3-oxo-C12-homoserine lactone directly suppressed NLRC4- and even NLRP3-mediated inflammasome assembly and activation. Taken together, our data indicate that QS system of P. aeruginosa facilitates bacteria to evade host inflammasome-dependent sensing machinery.

Advanced glycation end products regulate anabolic and catabolic activities via NLRP3-inflammasome activation in human nucleus pulposus cells

Intervertebral disc degeneration is widely recognized as a cause of lower back pain, neurological dysfunction and other musculoskeletal disorders. The major inflammatory cytokine IL‐1β is associated with intervertebral disc degeneration; however, the molecular mechanisms that drive IL‐1β production in the intervertebral disc, especially in nucleus pulposus (NP) cells, are unknown. In some tissues, advanced glycation end products (AGEs), which accumulate in NP tissues and promote its degeneration, increase oxidative stress and IL‐1β secretion, resulting in disorders, such as obesity, diabetes mellitus and ageing. It remains unclear whether AGEs exhibit similar effects in NP cells. In this study, we observed significant activation of the NLRP3 inflammasome in NP tissues obtained from patients with degenerative disc disease compared to that with idiopathic scoliosis according to results detected by Western blot and immunofluorescence. Using NP cells established from healthy tissues, our in vitro study revealed that AGEs induced an inflammatory response in NP cells and a degenerative phenotype in a NLRP3‐inflammasome‐dependent manner related to the receptor for AGEs (RAGE)/NF‐κB pathway and mitochondrial damage induced by mitochondrial reactive oxygen species (mtROS) generation, mitochondrial permeability transition pore (mPTP) activation and calcium mobilization. Among these signals, both RAGE and mitochondrial damage primed NLRP3 and pro‐IL‐1β activation as upstream signals of NF‐κB activity, whereas mitochondrial damage was critical for the assembly of inflammasome components. These results revealed that accumulation of AGEs in NP tissue may initiate inflammation‐related degeneration of the intervertebral disc via activation of the NLRP3 inflammasome.

Inflammation: A Double-Edged Sword in the Response to Pseudomonas aeruginosa Infection

The Gram-negative opportunistic pathogen Pseudomonas aeruginosa exploits failures of barrier defense and innate immunity to cause acute infections at a range of anatomic sites. We review the defense mechanisms that normally protect against P. aeruginosa pulmonary infection, as well as the bacterial products and activities that trigger their activation. Innate immune recognition of P. aeruginosa is critical for pathogen clearance; nonetheless, inflammation is also associated with pathogen persistence and poor host outcomes. We describe P. aeruginosa adaptations that improve this pathogen's fitness in the inflamed airway, and briefly discuss strategies to manipulate inflammation to benefit the host. Such adjunct therapies may become increasingly important in the treatment of acute and chronic infections caused by this multi-drug-resistant pathogen.

The Function of the Mitochondrial Calcium Uniporter in Neurodegenerative Disorders

The mitochondrial calcium uniporter (MCU)-a calcium uniporter on the inner membrane of mitochondria-controls the mitochondrial calcium uptake in normal and abnormal situations. Mitochondrial calcium is essential for the production of adenosine triphosphate (ATP); however, excessive calcium will induce mitochondrial dysfunction. Calcium homeostasis disruption and mitochondrial dysfunction is observed in many neurodegenerative disorders. However, the role and regulatory mechanism of the MCU in the development of these diseases are obscure. In this review, we summarize the role of the MCU in controlling oxidative stress-elevated mitochondrial calcium and its function in neurodegenerative disorders. Inhibition of the MCU signaling pathway might be a new target for the treatment of neurodegenerative disorders.

The endoplasmic reticulum-mitochondria coupling in health and disease: Molecules, functions and significance

The close apposition between endoplasmic reticulum (ER) and mitochondria represents a key platform, capable to regulate different fundamental cellular pathways. Among these, Ca²⁺ signaling and lipid homeostasis have been demonstrated over the last years to be deeply modulated by ER-mitochondria cross-talk. Given its importance in cell life/death decisions, increasing evidence suggests that alterations of the ER-mitochondria axis could be responsible for the onset and progression of several diseases, including neurodegeneration, cancer and obesity. However, the molecular identity of the proteins controlling this inter-organelle apposition is still debated. In this review, we summarize the main cellular pathways controlled by ER-mitochondria appositions, focusing on the principal molecules reported to be involved in this interplay and on those diseases for which alterations in organelles communication have been reported.

Hypoxia and sterile inflammation in cystic fibrosis airways: mechanisms and potential therapies

Cystic fibrosis is one of the most common autosomal recessive genetic diseases in Caucasian populations. Diagnosisvianewborn screening and targeted nutritional and antibiotic therapy have improved outcomes, however respiratory failure remains the key cause of morbidity and mortality. Progressive respiratory disease in cystic fibrosis is characterised by chronic neutrophilic airway inflammation associated with structural airway damage leading to bronchiectasis and decreased lung function. Mucus obstruction is a characteristic early abnormality in the cystic fibrosis airway, associated with neutrophilic inflammation often in the absence of detectable infection. Recent studies have suggested a link between hypoxic cell death and sterile neutrophilic inflammation in cystic fibrosis and other diseasesviathe IL-1 signalling pathway. In this review, we consider recent evidence regarding the cellular responses to respiratory hypoxia as a potential driver of sterile neutrophilic inflammation in the lung, current knowledge on hypoxia as a pathogenic mechanism in cystic fibrosis and the potential for current and future therapies to alleviate hypoxia-driven sterile inflammation.

Methods to Assess Mitochondrial Morphology in Mammalian Cells Mounting Autophagic or Mitophagic Responses

It is widely acknowledged that mitochondria are highly active structures that rapidly respond to cellular and environmental perturbations by changing their shape, number, and distribution. Mitochondrial remodeling is a key component of diverse biological processes, ranging from cell cycle progression to autophagy. In this chapter, we describe different methodologies for the morphological study of the mitochondrial network. Instructions are given for the preparation of samples for fluorescent microscopy, based on genetically encoded strategies or the employment of synthetic fluorescent dyes. We also propose detailed protocols to analyze mitochondrial morphometric parameters from both three-dimensional and bidimensional datasets. Finally, we describe a protocol for the visualization and quantification of mitochondrial structures through electron microscopy.

The burgeoning field of innate immune-mediated disease and autoinflammation

Immune-mediated autoinflammatory diseases are occupying an increasingly prominent position among the pantheon of debilitating conditions that afflict humankind. This review focuses on some of the key developments that have occurred since the original description of autoinflammatory disease in 1999, and focuses on underlying mechanisms that trigger autoinflammation. The monogenic autoinflammatory disease range has expanded considerably during that time, and now includes a broad spectrum of disorders, including relatively common conditions such as cystic fibrosis and subsets of systemic lupus erythematosus. The innate immune system also plays a key role in the pathogenesis of complex inflammatory disorders. We have proposed a new nomenclature to accommodate the rapidly increasing number of monogenic disorders, which predispose to either autoinflammation or autoimmunity or, indeed, combinations of both. This new terminology also encompasses a wide spectrum of genetically determined autoinflammatory diseases, with variable clinical manifestations of immunodeficiency and immune dysregulation/autoimmunity. We also explore some of the ramifications of the breakthrough discovery of the physiological role of pyrin and the search for identifiable factors that may serve to trigger attacks of autoinflammation. The evidence that pyrin, as part of the pyrin inflammasome, acts as a sensor of different inactivating bacterial modification Rho GTPases, rather than interacting directly with these microbial products, sets the stage for a better understanding of the role of microorganisms and infections in the autoinflammatory disorders. Finally, we discuss some of the triggers of autoinflammation as well as potential therapeutic interventions aimed at enhancing autophagy and proteasome degradation pathways. Copyright © 2016 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Bacterial secretion systems and regulation of inflammasome activation

Innate immunity is critical for host defenses against pathogens, but many bacteria display complex ways of interacting with innate immune signaling, as they may both activate and evade certain pathways. Gram-negative bacteria can exhibit specialized nanomachine secretion systems for delivery of effector proteins into mammalian cells. Bacterial types III, IV, and VI secretion systems (T3SS, T4SS, and T6SS) are known for their impact on caspase-1-activating inflammasomes, necessary for producing bioactive inflammatory cytokines IL-1β and IL-18, key participants of anti-bacterial responses. Here, we discuss how these secretion systems can mediate triggering and inhibition of inflammasome signaling. We propose that a fine balance between secretion system-mediated activation and inhibition can determine net activation of inflammasome activity and control inflammation, clearance, or spread of the infection.

Current Concepts and Controversies in Innate Immunity of Cystic Fibrosis Lung Disease

Cystic fibrosis (CF) lung disease is characterized by chronic infection and inflammation. The inflammatory response in CF is dominated by the activation of the innate immune system. Bacteria and fungi represent the key pathogens chronically colonizing the CF airways. In response, innate immune pattern recognition receptors, expressed by airway epithelial and myeloid cells, sense the microbial threat and release chemoattractants to recruit large numbers of neutrophils into CF airways. However, neutrophils fail to efficiently clear the invading pathogens, but instead release harmful proteases and oxidants and finally cause tissue injury. Here, we summarize and discuss current concepts and controversies in the field of innate immunity in CF lung disease, facing the ongoing questions of whether inflammation is good or bad in CF and how innate immune mechanisms could be harnessed therapeutically.

Mitochondrial reactive oxygen species and inflammation: Molecular mechanisms, diseases and promising therapies

Over the last few decades, many different groups have been engaged in studies of new roles for mitochondria, particularly the coupling of alterations in the redox pathway with the inflammatory responses involved in different diseases, including Alzheimer's disease, Parkinson's disease, atherosclerosis, cerebral cavernous malformations, cystic fibrosis and cancer. Mitochondrial dysfunction is important in these pathological conditions, suggesting a pivotal role for mitochondria in the coordination of pro-inflammatory signaling from the cytosol and signaling from other subcellular organelles. In this regard, mitochondrial reactive oxygen species are emerging as perfect liaisons that can trigger the assembly and successive activation of large caspase-1- activating complexes known as inflammasomes. This review offers a glimpse into the mechanisms by which inflammasomes are activated by mitochondrial mechanisms, including reactive oxygen species production and mitochondrial Ca²⁺ uptake, and the roles they can play in several inflammatory pathologies.

Recent insights into the molecular mechanisms of the NLRP3 inflammasome activation

Inflammasomes are high-molecular-weight protein complexes that are formed in the cytosolic compartment in response to danger- or pathogen-associated molecular patterns. These complexes enable activation of an inflammatory protease caspase-1, leading to a cell death process called pyroptosis and to proteolytic cleavage and release of pro-inflammatory cytokines interleukin (IL)-1β and IL-18. Along with caspase-1, inflammasome components include an adaptor protein, ASC, and a sensor protein, which triggers the inflammasome assembly in response to a danger signal. The inflammasome sensor proteins are pattern recognition receptors belonging either to the NOD-like receptor (NLR) or to the AIM2-like receptor family. While the molecular agonists that induce inflammasome formation by AIM2 and by several other NLRs have been identified, it is not well understood how the NLR family member NLRP3 is activated. Given that NLRP3 activation is relevant to a range of human pathological conditions, significant attempts are being made to elucidate the molecular mechanism of this process. In this review, we summarize the current knowledge on the molecular events that lead to activation of the NLRP3 inflammasome in response to a range of K (+) efflux-inducing danger signals. We also comment on the reported involvement of cytosolic Ca (2+) fluxes on NLRP3 activation. We outline the recent advances in research on the physiological and pharmacological mechanisms of regulation of NLRP3 responses, and we point to several open questions regarding the current model of NLRP3 activation.

Regulation and Function of the Nucleotide Binding Domain Leucine-Rich Repeat-Containing Receptor, Pyrin Domain-Containing-3 Inflammasome in Lung Disease

Inflammasomes are specialized inflammatory signaling platforms that govern the maturation and secretion of proinflammatory cytokines, such as IL-1β and IL-18, through the regulation of caspase-1-dependent proteolytic processing. Several nucleotide binding domain leucine-rich repeat-containing receptor (NLR) family members (i.e., NLR family, pyrin domain containing [NLRP] 1, NLRP3, and NLR family, caspase recruitment domain containing-4 [NLRC4]) as well as the pyrin and hemopoietic expression, interferon-inducibility, nuclear localization domain-containing family member, absent in melanoma 2, can form inflammasome complexes in human cells. In particular, the NLRP3 inflammasome is activated in response to cellular stresses through a two-component pathway, involving Toll-like receptor 4-ligand interaction (priming) followed by a second signal, such as ATP-dependent P2X purinoreceptor 7 receptor activation. Emerging studies suggest that the NLRP3 inflammasome can exert pleiotropic effects in human diseases with potentially both pro- and antipathogenic sequelae. Whereas NLRP3 inflammasome activation can serve as a vital component of host defense against invading bacteria and pathogens, excessive activation of the inflammasome can lead to inflammation-associated tissue injury in the setting of chronic disease. In addition, pyroptosis, an inflammasome-associated mode of cell death, contributes to host defense. Recent research has described the regulation and function of the NLRP3 inflammasome in various pulmonary diseases, including acute lung injury and acute respiratory distress syndrome, sepsis, respiratory infections, chronic obstructive pulmonary disease, asthma, pulmonary hypertension, cystic fibrosis, and idiopathic pulmonary fibrosis. The NLRP3 and related inflammasomes, and their regulated cytokines or receptors, may represent novel diagnostic or therapeutic targets in pulmonary diseases and other diseases in which inflammation contributes to pathogenesis.

IL-1 receptor antagonist ameliorates inflammasome-dependent inflammation in murine and human cystic fibrosis

Dysregulated inflammasome activation contributes to respiratory infections and pathologic airway inflammation. Through basic and translational approaches involving murine models and human genetic epidemiology, we show here the importance of the different inflammasomes in regulating inflammatory responses in mice and humans with cystic fibrosis (CF), a life-threatening disorder of the lungs and digestive system. While both contributing to pathogen clearance, NLRP3 more than NLRC4 contributes to deleterious inflammatory responses in CF and correlates with defective NLRC4-dependent IL-1Ra production. Disease susceptibility in mice and microbial colonization in humans occurrs in conditions of genetic deficiency of NLRC4 or IL-1Ra and can be rescued by administration of the recombinant IL-1Ra, anakinra. These results indicate that pathogenic NLRP3 activity in CF could be negatively regulated by IL-1Ra and provide a proof-of-concept evidence that inflammasomes are potential targets to limit the pathological consequences of microbial colonization in CF.

IL-1-mediated inflammation contributes to the pathogenesis of cystic fibrosis. Here the authors show that this is largely due to NLRP3 activation, whereas NLRP4 induces IL-1Ra, limiting the overall inflammasome activity and providing a therapeutic angle to ameliorate the disease.

Mitochondria in lung disease

Mitochondria are a distinguishing feature of eukaryotic cells. Best known for their critical function in energy production via oxidative phosphorylation (OXPHOS), mitochondria are essential for nutrient and oxygen sensing and for the regulation of critical cellular processes, including cell death and inflammation. Such diverse functional roles for organelles that were once thought to be simple may be attributed to their distinct heteroplasmic genome, exclusive maternal lineage of inheritance, and ability to generate signals to communicate with other cellular organelles. Mitochondria are now thought of as one of the cell's most sophisticated and dynamic responsive sensing systems. Specific signatures of mitochondrial dysfunction that are associated with disease pathogenesis and/or progression are becoming increasingly important. In particular, the centrality of mitochondria in the pathological processes and clinical phenotypes associated with a range of lung diseases is emerging. Understanding the molecular mechanisms regulating the mitochondrial processes of lung cells will help to better define phenotypes and clinical manifestations associated with respiratory disease and to identify potential diagnostic and therapeutic targets.

Pseudomonas aeruginosa Triggers Macrophage Autophagy To Escape Intracellular Killing by Activation of the NLRP3 Inflammasome

Assembly of the inflammasome has recently been identified to be a critical event in the initiation of inflammation. However, its role in bacterial killing remains unclear. Our study demonstrates that Pseudomonas aeruginosa infection induces the assembly of the NLRP3 inflammasome and the sequential secretion of caspase1 and interleukin-1β (IL-1β) in human macrophages. More importantly, activation of the NLRP3 inflammasome reduces the killing of P. aeruginosa in human macrophages, without affecting the generation of antimicrobial peptides, reactive oxygen species, and nitric oxide. In addition, our results demonstrate that P. aeruginosa infection increases the amount of the LC3-II protein and triggers the formation of autophagosomes in human macrophages. The P. aeruginosa-induced autophagy was enhanced by overexpression of NLRP3, ASC, or caspase1 but was reduced by knockdown of these core molecules of the NLRP3 inflammasome. Treatment with IL-1β enhanced autophagy in human macrophages. More importantly, IL-1β decreased the macrophage-mediated killing of P. aeruginosa, whereas knockdown of ATG7 or Beclin1 restored the IL-1β-mediated suppression of bacterial killing. Collectively, our study explores a novel mechanism employed by P. aeruginosa to escape from phagocyte killing and may provide a better understanding of the interaction between P. aeruginosa and host immune cells, including macrophages.

The molecular era of the mitochondrial calcium uniporter

The mitochondrial calcium uniporter is an evolutionarily conserved calcium channel, and its biophysical properties and relevance to cell death, bioenergetics and signalling have been investigated for decades. However, the genes encoding this channel have only recently been discovered, opening up a new 'molecular era' in the study of its biology. We now know that the uniporter is not a single protein but rather a macromolecular complex consisting of pore-forming and regulatory subunits. We review recent studies that harnessed the power of molecular biology and genetics to characterize the mechanism of action of the uniporter, its evolution and its contribution to physiology and human disease.

Mitochondrial Ca(2+) Remodeling is a Prime Factor in Oncogenic Behavior

Cancer is sustained by defects in the mechanisms underlying cell proliferation, mitochondrial metabolism, and cell death. Mitochondrial Ca²⁺ ions are central to all these processes, serving as signaling molecules with specific spatial localization, magnitude, and temporal characteristics. Mutations in mtDNA, aberrant expression and/or regulation of Ca²⁺-handling/transport proteins and abnormal Ca²⁺-dependent relationships among the cytosol, endoplasmic reticulum, and mitochondria can cause the deregulation of mitochondrial Ca²⁺-dependent pathways that are related to these processes, thus determining oncogenic behavior. In this review, we propose that mitochondrial Ca²⁺ remodeling plays a pivotal role in shaping the oncogenic signaling cascade, which is a required step for cancer formation and maintenance. We will describe recent studies that highlight the importance of mitochondria in inducing pivotal “cancer hallmarks” and discuss possible tools to manipulate mitochondrial Ca²⁺ to modulate cancer survival.

Mitochondria in autoinflammation: cause, mediator or bystander?

People suffering from autoinflammatory disease (AID) have recurring sterile inflammation due to dysregulated inflammasome activation. Although certain genes have been associated with several AIDs, the molecular underpinnings of seemingly spontaneous inflammation are not well understood. Emerging data now suggest that mitochondrial reactive oxygen species (ROS), mitochondrial DNA (mtDNA), and autophagy might drive key signaling pathways towards activation of the inflammasome. In this review, we discuss recent findings and highlight common features between different AIDs and mitochondrial (dys)function. Although it is still early to identify clear therapeutic targets, the emerging paradigms in inflammation and mitochondrial biology show that mitochondria play an important role in AIDs, and understanding this interplay will be key in the development of new therapies.