Annexin A1 Bioactive Peptide Promotes Resolution of Neuroinflammation in a Rat Model of Exsanguinating Cardiac Arrest Treated by Emergency Preservation and Resuscitation

ANXA1sp modulates the protective effect of Sirt3-induced mitophagy against sepsis-induced myocardial injury in mice

AIM

Sepsis-induced myocardial injury (SIMI) may be associated with insufficient mitophagy in cardiomyocytes, but the exact mechanism involved remains unknown. Sirtuin 3 (Sirt3) is mainly found in the mitochondrial matrix and is involved in repairing mitochondrial function through means such as the activation of autophagy. Previously, we demonstrated that the annexin-A1 small peptide (ANXA1sp) can promote Sirt3 expression in mitochondria. In this study, we hypothesized that the activation of Sirt3 by ANXA1sp induces mitophagy, thereby providing a protective effect against SIMI in mice.

METHODS

A mouse model of SIMI was established via cecal ligation and puncture. Intraperitoneal injections of ANXA1sp, 3TYP, and 3MA were administered prior to modeling. After successful modeling, IL-6, TNF-α, CK-MB, and CTn-I levels were measured; cardiac function was assessed using echocardiography; myocardial mitochondrial membrane potential, ROS, and ATP production were determined; myocardial mitochondrial ultrastructure was observed using transmission electron microscopy; and the expression levels of Sirt3 and autophagy-related proteins were detected using western blotting.

RESULTS

ANXA1sp significantly reduced serum IL-6, TNF-α, CK-MB, and CTn-I levels; decreased myocardial ROS production; increased mitochondrial membrane potential and ATP synthesis; and improved myocardial mitochondrial ultrastructure in septic mice. Furthermore, ANXA1sp promoted Sirt3 expression and activated the AMPK-mTOR pathway to induce myocardial mitophagy. These protective effects of ANXA1sp were reversed upon treatment with the Sirt3 blocker, 3-TYP.

CONCLUSION

ANXA1sp can reverse SIMI, and the underlying mechanism may be related to the activation of the AMPK-mTOR pathway following upregulation of Sirt3 by ANXA1sp, which, in turn, induces autophagy.

Annexin-A1 short peptide alleviates septic myocardial injury by upregulating SIRT3 and inhibiting myocardial cell apoptosis

Septic myocardial injury is a common complication of severe sepsis, which occurs in about 50% of cases. Patients with this disease may experience varying degrees of myocardial damage. Annexin-A1 short peptide (ANXA1sp), with a molecular structure of Ac-Gln-Ala-Tyr, has been reported to exert an organ protective effect in the perioperative period by modulating sirtuin-3 (SIRT3). Whether it possesses protective activity against sepsis-induced cardiomyopathy is worthy of study. This study aimed to investigate whether ANXA1sp exerts its anti-apoptotic effect in septic myocardial injury in vitro and in vivo via regulating SIRT3. In this study, we established in vivo and in vivo models of septic myocardial injury based on C57BL/6 mice and primary cardiomyocytes by lipopolysaccharide (LPS) induction. Results showed that ANXA1sp pretreatment enhanced the seven-day survival rate, improved left ventricular ejection fraction (EF), left ventricular fractional shortening (FS), and cardiac output (CO), and reduced the levels of creatine kinase-MB (CK-MB), cardiac troponin I (cTnI), and lactate dehydrogenase (LDH). Western blotting results revealed that ANXA1sp significantly increased the expression of SIRT3, Bcl-2, and downregulated Bax expression. TUNEL staining and flow cytometry results showed that ANXA1sp could attenuate the apoptosis rate of cardiomyocytes, whereas this anti-apoptotic effect was significantly attenuated after SIRT3 knockout. To sum up, ANXA1sp can alleviate LPS-induced myocardial injury by reducing myocardial apoptosis via SIRT3 upregulation.

Annexin A1 protects epidermal stem cells against ultraviolet-B irradiation-induced mitochondrial dysfunction

Ultraviolet-B (UV-B) radiation overexposure causes function impairment of epidermal stem cells (ESCs). We explored the mechanism of Annexin A1 (ANXA1) ameliorating UV-B-induced ESC mitochondrial dysfunction/cell injury. ESCs were cultured in vitro and irradiated with different doses of UV-B. Cell viability/ANXA1 protein level were assessed. After oe-ANXA1 transfection, ESCs were treated with oe-ANXA1/UV-B irradiation/CCCP/CCG-1423/3-methyladenine for 12 h. Cell viability/death, and adenosine triphosphate (ATP)/reactive oxygen species (ROS) levels were determined. Mitochondrial membrane potential (MMP) changes/DNA (mtDNA) content/oxygen consumption and RhoA activation were assessed. ROCK1/p-MYPT1/MYPT1/(LC3BII/I)/Beclin-1/p62 protein levels were determined. Mitochondrial morphology was observed. Mito-Tracker Green (MTG) and LC3B levels were determined. UV-B irradiation decreased cell viability/ANXA1 expression in a dose-dependent manner. UV-B-treated ESCs exhibited reduced cell viability/ATP content/MMP level/mitochondrial respiratory control ratio/mtDNA number/RhoA activity/MYPT1 phosphorylation/MTG+LC3B+ cells/(LC3BII/I) and Beclin-1 proteins, increased cell death/ROS/p62/IL-1β/IL-6/TNF-α expression, contracted mitochondrial, disappeared mitochondrial cristae, and increased vacuolar mitochondria, which were averted by ANXA1 overexpression, suggesting that UV-B induced ESC mitochondrial dysfunction/cell injury/inflammation by repressing mitophagy, but ANXA1 promoted mitophagy by activating the RhoA/ROCK1 pathway, thus repressing UV-B's effects. Mitophagy activation ameliorated UV-B-caused ESC mitochondrial dysfunction/cell injury/inflammation. Mitophagy inhibition partly diminished ANXA1-ameliorated UV-B's effects. Conjointly, ANXA1 promoted mitophagy by activating the RhoA/ROCK1 pathway, thereby improving UV-B-induced ESC mitochondrial dysfunction/cell injury.

ANXA1sp attenuates sepsis-induced myocardial injury by promoting mitochondrial biosynthesis and inhibiting oxidative stress and autophagy via SIRT3 upregulation

Sepsis-induced myocardial injury is one of the most difficult complications of sepsis in intensive care units. Annexin A1 (ANXA1) short peptide (ANXA1sp) protects organs during the perioperative period. However, the protective effect of ANXA1sp against sepsis-induced myocardial injury remains unclear. We aimed to explore the protective effects and mechanisms of ANXA1sp against sepsis-induced myocardial injury both in vitro and in vivo. Cellular and animal models of myocardial injury in sepsis were established with lipopolysaccharide. The cardiac function of mice was assessed by high-frequency echocardiography. Elisa assay detected changes in inflammatory mediators and markers of myocardial injury. Western blotting detected autophagy and mitochondrial biosynthesis-related proteins. Autophagic flux changes were observed by confocal microscopy, and autophagosomes were evaluated by TEM. ATP, SOD, ROS, and MDA levels were also detected.ANXA1sp pretreatment enhanced the 7-day survival rate, improved cardiac function, and reduced TNF-α, IL-6, IL-1β, CK-MB, cTnI, and LDH levels. ANXA1sp significantly increased the expression of sirtuin-3 (SIRT3), mitochondrial biosynthesis-related proteins peroxisome proliferator-activated receptor γ co-activator 1α (PGC-1α), and mitochondrial transcription factor A (TFAM). ANXA1sp increased mitochondrial membrane potential (△Ψm), ATP, and SOD, and decreased ROS, autophagy flux, the production of autophagosomes per unit area, and MDA levels. The protective effect of ANXA1sp decreased significantly after SIRT3 silencing in vitro and in vivo, indicating that the key factor in ANXA1sp's protective role is the upregulation of SIRT3. In summary, ANXA1sp attenuated sepsis-induced myocardial injury by upregulating SIRT3 to promote mitochondrial biosynthesis and inhibit oxidative stress and autophagy.

ANXA1sp Protects against Sepsis-Induced Myocardial Injury by Inhibiting Ferroptosis-Induced Cardiomyocyte Death via SIRT3-Mediated p53 Deacetylation

Sepsis-induced myocardial injury (SIMI), a common complication of sepsis, may cause significant mortality. Ferroptosis, a cell death associated with oxidative stress and inflammation, has been identified to be involved in SIMI. This study sought to investigate the role of ANXA1 small peptide (ANXA1sp) in SIMI pathogenesis. In this study, the mouse cardiomyocytes (H9C2 cells) were stimulated with lipopolysaccharide (LPS) to imitate SIMI in vitro. It was shown that ANXA1sp treatment substantially abated LPS-triggered H9C2 cell death and excessive secretion of proinflammatory cytokines (TNF-α, IL-1β, and IL-6). ANXA1sp pretreatment also reversed the increase of ROS and MDA generation as well as the decrease of SOD and GSH activity in H9C2 cells caused by LPS treatment. In addition, ANXA1sp considerably eliminated LPS-caused H9C2 cell ferroptosis, as revealed by the suppression of iron accumulation and the increase in GPX4 and FTH1 expression. Furthermore, the ameliorative effects of ANXA1sp on LPS-induced H9C2 cell damage could be partially abolished by erastin, a ferroptosis agonist. ANXA1sp enhanced SIRT3 expression in LPS-challenged H9C2 cells, thereby promoting p53 deacetylation. SIRT3 knockdown diminished ANXA1sp-mediated alleviation of cell death, inflammation, oxidative stress, and ferroptosis of LPS-treated H9C2 cells. Our study demonstrated that ANXA1sp is protected against LPS-induced cardiomyocyte damage by inhibiting ferroptosis-induced cell death via SIRT3-dependent p53 deacetylation, suggesting that ANXA1sp may be a potent therapeutic agent for SIMI.

The Effect of Early Application of Synthetic Peptides 19-2.5 and 19-4LF to Improve Survival and Neurological Outcome in a Mouse Model of Cardiac Arrest and Resuscitation

The synthetic antimicrobial peptides (sAMPs) Pep19-2.5 and Pep19-4LF have been shown in vitro and in vivo to reduce the release of pro-inflammatory cytokines, leading to the suppression of inflammation and immunomodulation. We hypothesized that intervention with Pep19-2.5 and Pep19-4LF immediately after cardiac arrest and resuscitation (CA-CPR) might attenuate immediate systemic inflammation, survival, and long-term outcomes in a standardized mouse model of CA-CPR. Long-term outcomes up to 28 days were assessed between a control group (saline) and two peptide intervention groups. Primarily, survival as well as neurological and cognitive parameters were assessed. In addition, systemic inflammatory molecules and specific biomarkers were analyzed in plasma as well as in brain tissue. Treatment with sAMPs did not provide any short- or long-term benefits for either survival or neurological outcomes, and no significant benefit on inflammation in the CA-CPR animal model. While no difference was found in the plasma analysis of early cytokines between the intervention groups four hours after resuscitation, a significant increase in UCH-L1, a biomarker of neuronal damage and blood–brain barrier rupture, was measured in the Pep19-4LF-treated group. The theoretical benefit of both sAMPs tested here for the treatment of post-cardiac arrest syndrome could not be proven.

Resolution Pharmacology: Focus on Pro-Resolving Annexin A1 and Lipid Mediators for Therapeutic Innovation in Inflammation

Chronic diseases that affect our society are made more complex by comorbidities and are poorly managed by the current pharmacology. While all present inflammatory etiopathogeneses, there is an unmet need for better clinical management of these diseases and their multiple symptoms. We discuss here an innovative approach based on the biology of the resolution of inflammation. Studying endogenous pro-resolving peptide and lipid mediators, how they are formed, and which target they interact with, can offer innovative options through augmenting the expression or function of pro-resolving pathways or mimicking their actions with novel targeted molecules. In all cases, resolution offers innovation for the treatment of the primary cause of a given disease and/or for the management of its comorbidities, ultimately improving patient quality of life. By implementing resolution pharmacology, we harness the whole physiology of inflammation, with the potential to bring a marked change in the management of inflammatory conditions.

Promiscuous Receptors and Neuroinflammation: The Formyl Peptide Class

Formyl peptide receptors, abbreviated as FPRs in humans, are G-protein coupled receptors (GPCRs) mainly found in mammalian leukocytes. However, they are also expressed in cell types crucial for homeostatic brain regulation, including microglia and blood-brain barrier endothelial cells. Thus, the roles of these immune-associated receptors are extensive, from governing cellular adhesion and directed migration through chemotaxis, to granule release and superoxide formation, to phagocytosis and efferocytosis. In this review, we will describe the similarities and differences between the two principal pro-inflammatory and anti-inflammatory FPRs, FPR1 and FPR2, and the evidence for their importance in the development of neuroinflammatory disease, alongside their potential as therapeutic targets.

Deficiency of MST1 in endometriosis related peritoneal macrophages promoted the autophagy of ectopic endometrial stromal cells by IL-10

Changes in the function of peritoneal macrophages contribute to the homeostasis of the peritoneal immune microenvironment in endometriosis. The mechanism by which ectopic tissues escape phagocytic clearance by macrophages to achieve ectopic colonization and proliferation is unknown. The expression of CD163 in peritoneal macrophages in patients with endometriosis is increased, with the overexpression of MAPK, which can promote the M2-type polarization of macrophages and reduce their ability to phagocytose ectopic endometrial cells. As an upstream regulator of MAPK, MST1 expression is deficient in peritoneal macrophages of patients with endometriosis. This process is regulated by miR-887-5p, a noncoding RNA targeting MST1. Moreover, MST1-knockout macrophages secrete anti-inflammatory factor IL-10, which promotes autophagy of ectopic endometrial stromal cells. These results suggest that MST1 deficient macrophages may accelerate the autophagy of ectopic endometrium via IL-10 which was regulated by miR-887-5p.

Mitochondrial sirtuin 3 and various cell death modalities

Sirtuin 3, a member of the mammalian sirtuin family of proteins, is involved in the regulation of multiple processes in cells. It is a major mitochondrial NAD⁺-dependent deacetylase with a broad range of functions, such as regulation of oxidative stress, reprogramming of tumor cell energy pathways, and metabolic homeostasis. One of the intriguing functions of sirtuin 3 is the regulation of mitochondrial outer membrane permeabilization, a key step in apoptosis initiation/progression. Moreover, sirtuin 3 is involved in the execution of various cell death modalities, which makes sirtuin 3 a possible regulator of crosstalk between them. This review is focused on the role of sirtuin 3 as a target for tumor cell elimination and how mitochondria and reactive oxygen species (ROS) are implicated in this process.

Annexin-A1 Tripeptide Attenuates Surgery-Induced Neuroinflammation and Memory Deficits Through Regulation the NLRP3 Inflammasome

Neuroinflammation is a growing hallmark of perioperative neurocognitive disorders (PNDs), including delirium and longer-lasting cognitive deficits. We have developed a clinically relevant orthopedic mouse model to study the impact of a common surgical procedure on the vulnerable brain. The mechanism underlying PNDs remains unknown. Here we evaluated the impact of surgical trauma on the NLRP3 inflammasome signaling, including the expression of apoptosis-associated speck-like protein containing a CARD (ASC), caspase-1, and IL-1β in the hippocampus of C57BL6/J male mice, adult (3-months) and aged (>18-months). Surgery triggered ASC specks formation in CA1 hippocampal microglia, but without inducing significant morphological changes in NLRP3 and ASC knockout mice. Since no therapies are currently available to treat PNDs, we assessed the neuroprotective effects of a biomimetic peptide derived from the endogenous inflammation-ending molecule, Annexin-A1 (ANXA1). We found that this peptide (ANXA1sp) inhibited postoperative NLRP3 inflammasome activation and prevented microglial activation in the hippocampus, reducing PND-like memory deficits. Together our results reveal a previously under-recognized role of hippocampal ANXA1 and NLRP3 inflammasome dysregulation in triggering postoperative neuroinflammation, offering a new target for advancing treatment of PNDs through the resolution of inflammation.

Early Post-ischemic Brain Glucose Metabolism Is Dependent on Function of TLR2: a Study Using [18F]F-FDG PET-CT in a Mouse Model of Cardiac Arrest and Cardiopulmonary Resuscitation

Purpose

The mammalian brain glucose metabolism is tightly and sensitively regulated. An ischemic brain injury caused by cardiac arrest (CA) and cardiopulmonary resuscitation (CPR) affects cerebral function and presumably also glucose metabolism. The majority of patients who survive CA suffer from cognitive deficits and physical disabilities. Toll-like receptor 2 (TLR2) plays a crucial role in inflammatory response in ischemia and reperfusion (I/R). Since deficiency of TLR2 was associated with increased survival after CA-CPR, in this study, glucose metabolism was measured using non-invasive [¹⁸F]F-FDG PET-CT imaging before and early after CA-CPR in a mouse model comparing wild-type (WT) and TLR2-deficient (TLR2^−/−) mice. The investigation will evaluate whether FDG-PET could be useful as an additional methodology in assessing prognosis.

Procedures

Two PET-CT scans using 2-deoxy-2-[¹⁸F]fluoro-D-glucose ([¹⁸F]F-FDG) tracer were carried out to measure dynamic glucose metabolism before and early after CPR. To achieve this, anesthetized and ventilated adult female WT and TLR2^−/− mice were scanned in PET-CT. After recovery from the baseline scan, the same animals underwent 10-min KCL-induced CA followed by CPR. Approximately 90 min after CA, measurements of [¹⁸F]F-FDG uptake for 60 min were started. The [¹⁸F]F-FDG standardized uptake values (SUVs) were calculated using PMOD-Software on fused FDG-PET-CT images with the included 3D Mirrione-Mouse-Brain-Atlas.

Results

The absolute SUV_mean of glucose in the whole brain of WT mice was increased about 25.6% after CA-CPR. In contrast, the absolute glucose SUV in the whole brain of TLR2^−/− mice was not significantly different between baseline and measurements post CA-CPR. In comparison, baseline measurements of both mouse strains show a highly significant difference with regard to the absolute glucose SUV in the whole brain. Values of TLR2^−/− mice revealed a 34.6% higher glucose uptake.

Conclusions

The altered mouse strains presented a different pattern in glucose uptake under normal and ischemic conditions, whereby the post-ischemic differences in glucose metabolism were associated with the function of key immune factor TLR2. There is evidence for using early FDG-PET-CT as an additional diagnostic tool after resuscitation. Further studies are needed to use PET-CT in predicting neurological outcomes.

Annexin A1 Tripeptide Mimetic Increases Sirtuin-3 and Augments Mitochondrial Function to Limit Ischemic Kidney Injury

Background: Acute kidney injury (AKI) is one of the most common organ failures following surgery. We have developed a tripeptide mimetic (ANXA1sp) of the parent annexin A1 molecule that shows promise as an organ protectant limiting cellular stress; however, its potential as a kidney protective agent remains unexplored, and its mechanism of action is poorly understood. Our hypothesis was that ANXA1sp would limit kidney injury following surgical ischemic kidney injury. Methods: In a blinded fashion, wildtype mice were assigned to receive vehicle control or ANXA1sp one hour prior to and one hour after kidney vascular clamping. Our primary outcomes were markers of kidney injury and function as measured by serum creatinine and histologic injury scoring of kidney tissue sections. Immunofluorescence microscopy, real-time PCR, and Western blot were used to assess cell death, oxidative stress, and mitochondrial biomarkers. An in vitro model of oxygen-glucose deprivation in immortalized kidney tubule cells was used. Results: ANXA1sp given prior to and after ischemic kidney injury abrogated ischemic kidney injury. ANXA1sp limited cell death both in vivo and in vitro and abrogated oxidative stress following ischemia. ANXA1sp significantly increased the expression of markers associated with protective mitophagy and limited the expression of markers associated with detrimental mitochondrial fission. ANXA1sp upregulated the expression of the mitochondrial protectant sirtuin-3 (SIRT3) in the mitochondria of kidney tubular cells. Silencing of SIRT3 reversed ANXA1sp-mediated protection against hypoxic cell death. Conclusions: ANXA1sp limits kidney injury, upregulates SIRT3, and preserves mitochondrial integrity following ischemic kidney injury. ANXA1sp holds considerable promise as a perioperative kidney protectant prior to ischemia inducing surgery and kidney transplantation.

Dexmedetomidine post-conditioning attenuates cerebral ischemia following asphyxia cardiac arrest through down-regulation of apoptosis and neuroinflammation in rats

Background

Neuroprotection strategies after cardiac arrest (CA)/cardiopulmonary resuscitation (CPR) remain key areas of basic and clinical research. This study was designed to investigate the neuroprotective effects of dexmedetomidine following resuscitation and potential mechanisms.

Methods

Anesthetized rats underwent 6-min asphyxia-based cardiac arrest and resuscitation, after which the experimental group received a single intravenous dose of dexmedetomidine (25 μg/kg). Neurological outcomes and ataxia were assessed after the return of spontaneous circulation. The serum levels and brain expression of inflammation markers was examined, and apoptotic cells were quantified by TUNEL staining.

Results

Neuroprotection was enhanced by dexmedetomidine post-conditioning after the return of spontaneous circulation. This enhancement was characterized by the promotion of neurological function scores and coordination. In addition, dexmedetomidine post-conditioning attenuated the serum levels of the pro-inflammatory cytokine tumor necrosis factor (TNF)-α at 2 h, as well as interleukin IL-1β at 2, 24, and 48 h. TUNEL staining showed that the number of apoptotic cells in the dexmedetomidine post-conditioning group was significantly reduced compared with the control group. Further western blot analysis indicated that dexmedetomidine markedly reduced the levels of caspase-3 and nuclear factor-kappa B (NF-κB) in the brain.

Conclusions

Dexmedetomidine post-conditioning had a neuroprotective effect against cerebral injury following asphyxia-induced cardiac arrest. The mechanism was associated with the downregulation of apoptosis and neuroinflammation.

Palmitic acid methyl ester inhibits cardiac arrest-induced neuroinflammation and mitochondrial dysfunction

We previously discovered that palmitic acid methyl ester (PAME) is a potent vasodilator released from the sympathetic ganglion with vasoactive properties. Post-treatment with PAME can enhance cortical cerebral blood flow and functional learning and memory, while inhibiting neuronal cell death in the CA1 region of the hippocampus under pathological conditions (i.e. cerebral ischemia). Since mechanisms underlying PAME-mediated neuroprotection remain unclear, we investigated the possible neuroprotective mechanisms of PAME after 6 min of asphyxial cardiac arrest (ACA, an animal model of global cerebral ischemia). Our results from capillary-based immunoassay (for the detection of proteins) and cytokine array suggest that PAME (0.02 mg/kg) can decrease neuroinflammatory markers, such as ionized calcium binding adaptor molecule 1 (Iba1, a specific marker for microglia/macrophage activation) and inflammatory cytokines after cardiopulmonary resuscitation. Additionally, the mitochondrial oxygen consumption rate (OCR) and respiratory function in the hippocampal slices were restored following ACA (via Seahorse XF24 Extracellular Flux Analyzer) suggesting that PAME can ameliorate mitochondrial dysfunction. Finally, hippocampal protein arginine methyltransferase 1 (PRMT1) and PRMT8 are enhanced in the presence of PAME to suggest a possible pathway of methylated fatty acids to modulate arginine-based enzymatic methylation. Altogether, our findings suggest that PAME can provide neuroprotection in the presence of ACA to alleviate neuroinflammation and ameliorate mitochondrial dysfunction.

Rationale for the Use of Radiation-Activated Mesenchymal Stromal/Stem Cells in Acute Respiratory Distress Syndrome

We have previously shown that the combination of radiotherapy with human umbilical-cord-derived mesenchymal stromal/stem cells (MSCs) cell therapy significantly reduces the size of the xenotumors in mice, both in the directly irradiated tumor and in the distant nonirradiated tumor or its metastasis. We have also shown that exosomes secreted from MSCs preirradiated with 2 Gy are quantitatively, functionally and qualitatively different from the exosomes secreted from nonirradiated mesenchymal cells, and also that proteins, exosomes and microvesicles secreted by MSCs suffer a significant change when the cells are activated or nonactivated, with the amount of protein present in the exosomes of the preirradiated cells being 1.5 times greater compared to those from nonirradiated cells. This finding correlates with a dramatic increase in the antitumor activity of the radiotherapy when is combined with MSCs or with preirradiated mesenchymal stromal/stem cells (MSCs*). After the proteomic analysis of the load of the exosomes released from both irradiated and nonirradiated cells, we conclude that annexin A1 is the most important and significant difference between the exosomes released by the cells in either status. Knowing the role of annexin A1 in the control of hypoxia and inflammation that is characteristic of acute respiratory-distress syndrome (ARDS), we designed a hypothetical therapeutic strategy, based on the transplantation of mesenchymal stromal/stem cells stimulated with radiation, to alleviate the symptoms of patients who, due to pneumonia caused by SARS-CoV-2, require to be admitted to an intensive care unit for patients with life-threatening conditions. With this hypothesis, we seek to improve the patients' respiratory capacity and increase the expectations of their cure.

Potential relationship between Sirt3 and autophagy in ovarian cancer

Sirtuin 3 (Sirt3) is an important member of the sirtuin protein family. It is a deacetylase that was previously reported to modulate the level of reactive oxygen species (ROS) production and limit the extent of oxidative damage in cellular components. As an important member of the class III type of histone deacetylases, Sirt3 has also been documented to mediate nuclear gene expression, metabolic control, neuroprotection, cell cycle and proliferation. In ovarian cancer (OC), Sirt3 has been reported to regulate cellular metabolism, apoptosis and autophagy. Sirt3 can regulate autophagy through a variety of different molecular signaling pathways, including the p62, 5'AMP-activated protein kinase and mitochondrial ROS-superoxide dismutase pathways. However, autophagy downstream of Sirt3 and its association with OC remains poorly understood. In the present review, the known characteristics of Sirt3 and autophagy were outlined, and their potential functional roles were discussed. Following a comprehensive analysis of the current literature, Sirt3 and autophagy may either serve positive or negative roles in the regulation of OC. Therefore, it is important to identify the appropriate expression level of Sirt3 to control the activation of autophagy in OC cells. This strategy may prove to be a novel therapeutic method to reduce the mortality of patients with OC. Finally, potential research directions into the association between Sirt3 and other signaling pathways were provided.

Enhancing the Bystander and Abscopal Effects to Improve Radiotherapy Outcomes

In this paper, we summarize published articles and experiences related to the attempt to improve radiotherapy outcomes and, thus, to personalize the radiation treatment according to the individual characteristics of each patient. The evolution of ideas and the study of successively published data have led us to envisage new biophysical models for the interpretation of tumor and healthy normal tissue response to radiation. In the development of the model, we have shown that when mesenchymal stem cells (MSCs) and radiotherapy are administered simultaneously in experimental radiotherapy on xenotumors implanted in a murine model, the results of the treatment show the existence of a synergic mechanism that is able to enhance the local and systemic actions of the radiation both on the treated tumor and on its possible metastasis. We are convinced that, due to the physical hallmarks that characterize the neoplastic tissues, the physical-chemical tropism of MSCs, and the widespread functions of macromolecules, proteins, and exosomes released from activated MSCs, the combination of radiotherapy plus MSCs used intratumorally has the effect of counteracting the pro-tumorigenic and pro-metastatic signals that contribute to the growth, spread, and resistance of the tumor cells. Therefore, we have concluded that MSCs are appropriate for therapeutic use in a clinical trial for rectal cancer combined with radiotherapy, which we are going to start in the near future.