Moderate-intensity aerobic exercise training improves CD8+ tumor-infiltrating lymphocytes effector function by reducing mitochondrial loss.

Aerobic exercise training (AET) has emerged as a strategy to reduce cancer mortality, however, the mechanisms explaining AET on tumor development remain unclear. Tumors escape immune detection by generating immunosuppressive microenvironments and impaired T cell function, which is associated with T cell mitochondrial loss. AET improves mitochondrial content and function, thus we tested whether AET would modulate mitochondrial metabolism in tumor-infiltrating lymphocytes (TIL). Balb/c mice were subjected to a treadmill AET protocol prior to CT26 colon carcinoma cells injection and until tumor harvest. Tissue hypoxia, TIL infiltration and effector function, and mitochondrial content, morphology and function were evaluated. AET reduced tumor growth, improved survival, and decreased tumor hypoxia. An increased CD8+ TIL infiltration, IFN-γ and ATP production promoted by AET was correlated with reduced mitochondrial loss in these cells. Collectively, AET decreases tumor growth partially by increasing CD8+ TIL effector function through an improvement in their mitochondrial content and function.

Physical exercise as a friend not a foe in acute kidney diseases through immune system modulation.

Regular and moderate exercise is being used for therapeutic purposes in treating several diseases, including cancer, cardiovascular diseases, arthritis, and even chronic kidney diseases (CKDs). Conversely, extenuating physical exercise has long been pointed out as one of the sources of acute kidney injury (AKI) due to its severe impact on the body's physiology. AKI development is associated with increased tubular necrosis, which initiates a cascade of inflammatory responses. The latter involves cytokine production, immune cell (macrophages, lymphocytes, and neutrophils, among others) activation, and increased oxidative stress. AKI can induce prolonged fibrosis stimulation, leading to CKD development. The need for therapeutic alternative treatments for AKI is still a relevant issue. In this context arises the question as to whether moderate, not extenuating, exercise could, on some level, prevent AKI. Several studies have shown that moderate exercise can help reduce tissue damage and increase the functional recovery of the kidneys after an acute injury. In particular, the immune system can be modulated by exercise, leading to a better recovery from different pathologies. In this review, we aimed to explore the role of exercise not as a trigger of AKI, but as a modulator of the inflammatory/immune system in the prevention or recovery from AKI in different scenarios. In AKI induced by ischemia and reperfusion, sepsis, diabetes, antibiotics, or chemotherapy, regular and/or moderate exercise could modulate the immune system toward a more regulatory immune response, presenting, in general, an anti-inflammatory profile. Exercise was shown to diminish oxidative stress, inflammatory markers (caspase-3, lactate dehydrogenase, and nitric oxide), inflammatory cytokines (interleukin (IL)-1b, IL-6, IL-8, and tumor necrosis factor-α (TNF-α)), modulate lymphocytes to an immune suppressive phenotype, and decrease tumor necrosis factor-ß (TGF-ß), a cytokine associated with fibrosis development. Thus, it creates an AKI recovery environment with less tissue damage, hypoxia, apoptosis, or fibrosis. In conclusion, the practice of regular moderate physical exercise has an impact on the immune system, favoring a regulatory and anti-inflammatory profile that prevents the occurrence of AKI and/or assists in the recovery from AKI. Moderate exercise should be considered for patients with AKI as a complementary therapy.

Vagal electrostimulation in postoperative thoracic surgery reduces the systemic inflammatory response and cardiopulmonary complications: an experimental study in pigs.

Background: Conventional thoracotomy (CT) often leads to systemic inflammatory response syndrome (SIRS), which induces several clinical complications. CT remains widely used in low-income institutions. Although minimally invasive surgical procedures, such as robotic surgery (RS), have been used to prevent many of the complications inherit from the surgical procedure. Here, we investigated the protective effect of vagus nerve stimulation (VNS) in a pre-clinical model during CT or RS and postoperative period (POP) relative to clinical complications and inflammatory control. The objective was to compare hemodynamic features and cytokine levels in the blood, lung, and bronchoalveolar lavage (BAL) fluids of animals subjected to CT or RS with or without VNS. Methods: Twenty-four minipigs were subjected to 12 animals CT and 12 animals RS, with or without VNS, and accompanied 24 h later by pulmonary lobectomy. Blood samples for evaluating the hemodynamic parameters were collected before the surgical preparation, immediately after the beginning of VNS, and every 4 h until 24 h after the lobectomy. BAL fluid and lung tissue were collected at the end of the experiment. Cytokine levels were evaluated in the blood, BAL fluid, and lung tissues. Results: VNS maintained a more stable heart rate during POP and decreased the incidence of overall cardiac complications while preventing increase in IL-6 levels 12 h after lobectomy, compared to sham animals. No differences were found in cytokine expression in the BAL fluid and lung tissue in any of the studied groups. Conclusions: Taken together, our data suggested that VNS should be considered a non-pharmacological tool in the prevention of the exacerbated inflammatory response responsible for severe clinical complications, especially in more aggressive surgical procedures.

A scoping review of graphene-based biomaterials for in vivo bone tissue engineering.

The growing demand for more efficient materials for medical applications brought together two previously distinct fields: medicine and engineering. Regenerative medicine has evolved with the engineering contributions to improve materials and devices for medical use. In this regard, graphene is one of the most promising materials for bone tissue engineering and its potential for bone repair has been studied by several research groups. The aim of this study is to conduct a scoping review including articles published in the last 12 years (from 2010 to 2022) that have used graphene and its derivatives (graphene oxide and reduced graphene) in preclinical studies for bone tissue regeneration, searching in PubMed/MEDLINE, Embase, Web of Science, Cochrane Central, and clinicaltrials.gov (to confirm no study has started with clinical trial). Boolean searches were performed using the defined key words "bone" and "graphene", and manuscript abstracts were uploaded to Rayyan, a web-tool for systematic and scoping reviews. This scoping review was conducted based on Joanna Briggs Institute Manual for Scoping Reviews and the report follows the recommendations of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses - Extension for Scoping Reviews (PRISMA-ScR) statement. After the search protocol and application of the inclusion criteria, 77 studies were selected and evaluated by five blinded researchers. Most of the selected studies used composite materials associated with graphene and its derivatives to natural and synthetic polymers, bioglass, and others. Although a variety of graphene materials were analyzed in these studies, they all concluded that graphene, its derivatives, and its composites improve bone repair processes by increasing osteoconductivity, osteoinductivity, new bone formation, and angiogenesis. Thus, this systematic review opens up new opportunities for the development of novel strategies for bone tissue engineering with graphene.

AKT inhibition interferes with the expression of immune checkpoint proteins and increases NK-induced killing of HL60-AML cells.

OBJECTIVE: To determine the role of the AKT pathway in the regulating of natural Killer-induced apoptosis of acute myeloid leukemia cells and to characterize the associated molecular mechanisms. METHODS: BALB/c nude mice were injected with HL60 cells to induce a xenogenic model of subcutaneous leukemic tumors. Mice were treated with perifosine, and their spleens were analyzed using biometry, histopathology, and immunohistochemistry. Gene expression analysis in leukemia cells was performed by real-time PCR. Protein analysis of leukemia and natural Killer cells was performed by flow cytometry. AKT inhibition in HL60 cells, followed by co-culture with natural Killer cells was performed to assess cytotoxicity. Apoptosis rate was quantified using flow cytometry. RESULTS: Perifosine treatment caused a reduction in leukemic infiltration in the spleens of BALB/c nude mice. In vitro , AKT inhibition reduced HL60 resistance to natural Killer-induced apoptosis. AKT inhibition suppressed the immune checkpoint proteins PD-L1, galectin-9, and CD122 in HL60 cells, but did not change the expression of their co-receptors PD1, Tim3, and CD96 on the natural Killer cell surface. In addition, the death receptors DR4, TNFR1, and FAS were overexpressed by AKT inhibition, thus increasing the susceptibility of HL60 cells to the extrinsic pathway of apoptosis. CONCLUSION: The AKT pathway is involved in resistance to natural Killer-induced apoptosis in HL60 cells by regulating the expression of immune suppressor receptors. These findings highlight the importance of AKT in contributing to immune evasion mechanisms in acute myeloid leukemia and suggests the potential of AKT inhibition as an adjunct to immunotherapy.

Suspected Germline TP53 Variants and Clonal Hematopoiesis of Indeterminate Potential: Lessons Learned From a Molecular Tumor Board.

OBJECTIVE: Li-Fraumeni syndrome (LFS) is a pan-cancer predisposition syndrome caused by germline pathogenic variants in the gene TP53. The interpretation of TP53 variants in clinical scenarios outside the classic LFS criteria may be challenging. Here, we report a patient affected by 2 primary cancers at later ages, who harbored a likely pathogenic TP53 at low allele frequency detected in a blood sample. METHODS: The Molecular Tumor Board committee at our institution revisited the case of a patient who was enrolled in a research protocol for the investigation of genetic conditions associated with neuroendocrine tumors. Clinical, familial, and molecular data were reviewed. The patient received germline testing using a next generation sequencing multi-gene panel and was incidentally found to harbor a TP53 likely pathogenic variant, with 22% of variant allele fraction. Additional samples, including a second blood sample, oral swab, and saliva, were collected for DNA analysis. A new TP53 sequencing round was performed with the attempt to distinguish between a true constitutional germline variant and a somatically acquired variant due to aberrant clonal expansion of bone marrow precursors. RESULTS: Patient's personal and familial history of cancer did not meet classic nor Chompret LFS criteria. Environmental risk factors for cancer were identified, such as alcohol abuse and tobacco exposure. The TP53 variant initially found in the next-generation sequencing was confirmed by Sanger sequencing in the previous DNA sample extracted from blood for the first analysis and in a second blood sample collected 6 years later. The TP53 variant was not detected in the DNA extracted from the oral swab and saliva samples. CONCLUSION: Considering the low TP53 variant allele fraction in blood, absence of variant detection in oral swab and saliva samples, the lack of LFS clinical criteria, and history of exposure to environmental risk factors for cancer, the main hypothesis for this case was aberrant clonal expansion due to clonal hematopoiesis. Oncologists should interpret TP53 findings during germline testing with caution.

In vitro differentiation of myeloid suppressor cells (MDSC-like) from an immature myelomonocytic precursor THP-1.

BACKGROUND: Myeloid-derived suppressor cells (MDSCs) are a heterogeneous population with a potent suppressor profile that regulates immune responses. These cells are one of the main components of the microenvironment of several diseases, including solid and hematologic tumors, autoimmunities, and chronic inflammation. However, their wide use in studies is limited due to they comprehend a rare population, which is difficult to isolate, expand, differentiate, and maintain in culture. Additionally, this population has a complex phenotypic and functional characterization. OBJECTIVE: To develop a protocol for the in vitro production of MDSC-like population from the differentiation of the immature myeloid cell line THP-1. METHODS: We stimulated THP-1 with G-CSF (100 ng/mL) and IL-4 (20 ng/mL) for seven days to differentiate into the MDSC-like profile. At the end of the protocol, we characterized these cells phenotypically and functionally by immunophenotyping, gene expression analysis, cytokine release dosage, lymphocyte proliferation, and NK-mediated killing essays. RESULTS: We differentiate THP-1 cells in an MDSC-like population, named THP1-MDSC-like, which presented immunophenotyping and gene expression profiles compatible with that described in the literature. Furthermore, we verified that this phenotypic and functional differentiation did not deviate to a macrophage profile of M1 or M2. These THP1-MDSC-like cells secreted several immunoregulatory cytokines into the microenvironment, consistent with the suppressor profile related to MDSC. In addition, the supernatant of these cells decreased the proliferation of activated lymphocytes and impaired the apoptosis of leukemic cells induced by NK cells. CONCLUSIONS: We developed an effective protocol for MDSC in vitro production from the differentiation of the immature myeloid cell line THP-1 induced by G-CSF and IL-4. Furthermore, we demonstrated that THP1-MDSC-like suppressor cells contribute to the immune escape of AML cells. Potentially, these THP1-MDSC-like cells can be applied on a large-scale platform, thus being able to impact the course of several studies and models such as cancer, immunodeficiencies, autoimmunity, and chronic inflammation.

AKT inhibition interferes with the expression of immune checkpoint proteins and increases NK-induced killing of HL60-AML cells

ABSTRACT Objective To determine the role of the AKT pathway in the regulating of natural Killer-induced apoptosis of acute myeloid leukemia cells and to characterize the associated molecular mechanisms. Methods BALB/c nude mice were injected with HL60 cells to induce a xenogenic model of subcutaneous leukemic tumors. Mice were treated with perifosine, and their spleens were analyzed using biometry, histopathology, and immunohistochemistry. Gene expression analysis in leukemia cells was performed by real-time PCR. Protein analysis of leukemia and natural Killer cells was performed by flow cytometry. AKT inhibition in HL60 cells, followed by co-culture with natural Killer cells was performed to assess cytotoxicity. Apoptosis rate was quantified using flow cytometry. Results Perifosine treatment caused a reduction in leukemic infiltration in the spleens of BALB/c nude mice. In vitro , AKT inhibition reduced HL60 resistance to natural Killer-induced apoptosis. AKT inhibition suppressed the immune checkpoint proteins PD-L1, galectin-9, and CD122 in HL60 cells, but did not change the expression of their co-receptors PD1, Tim3, and CD96 on the natural Killer cell surface. In addition, the death receptors DR4, TNFR1, and FAS were overexpressed by AKT inhibition, thus increasing the susceptibility of HL60 cells to the extrinsic pathway of apoptosis. Conclusion The AKT pathway is involved in resistance to natural Killer-induced apoptosis in HL60 cells by regulating the expression of immune suppressor receptors. These findings highlight the importance of AKT in contributing to immune evasion mechanisms in acute myeloid leukemia and suggests the potential of AKT inhibition as an adjunct to immunotherapy.

Adult acute lymphoblastic leukemia in a resource-constrained setting: outcomes after expansion of genetic evaluation.

Acute lymphoblastic leukemia (ALL) is a challenging disease with a growing genetic landscape, even though there is substantial gap between developed and non-developed countries when it comes to availability of such new technologies. This manuscript reports a 5-year retrospective cohort of newly diagnosed ALL patients and their genetic findings and outcomes. An expanded genetic evaluation by using FISH and RT-PCR was implemented, aiming to identify Ph-like alterations. Patients were treated according to our local protocol, which allocated patients according to age and Philadelphia-chromosome status. A total of 104 patients was included, with median age of 37.5 years. Philadelphia chromosome was detected in 33 cases of B-lineage. Among 45 Ph-negative B-lineage, after excluding KMT2A or TCF3-PBX1 cases, we identified 9 cases with Ph-like fusion. Ph-positive and Ph-like patients had higher initial WBC (p = 0.06). Out of 104 cases, two cases did not start chemotherapy and an early death rate of 10.8% was found. Allogeneic transplantation was performed in 18 cases, being ten performed in first CR. Three-year overall survival (OS) and 3-year event-free survival were 42.8% and 30.8%, respectively. For patients treated with a pediatric regimen, 3-year OS was 52.5%. Extramedullary disease (HR 0.42) and platelet counts (HR 0.9) were independently associated with OS. We still face excessive non-relapse mortality that compromises our results. Alternative strategies implementing FISH and RT-PCR are feasible and able to identify Ph-like fusions. Delays in allogeneic transplantation, as well as the unavailability of new agents, impact long-term survival. Measures to decrease early infection are desirable.

Loss of mTORC2 Activity in Neutrophils Impairs Fusion of Granules and Affects Cellular Metabolism Favoring Increased Bacterial Burden in Sepsis.

Sepsis is a complex infectious syndrome in which neutrophil participation is crucial for patient survival. Neutrophils quickly sense and eliminate the pathogen by using different effector mechanisms controlled by metabolic processes. The mammalian target of rapamycin (mTOR) pathway is an important route for metabolic regulation, and its role in neutrophil metabolism has not been fully understood yet, especially the importance of mTOR complex 2 (mTORC2) in the neutrophil effector functions. In this study, we observed that the loss of Rictor (mTORC2 scaffold protein) in primary mouse-derived neutrophils affects their chemotaxis by fMLF and their microbial killing capacity, but not the phagocytic capacity. We found that the microbicidal capacity was impaired in Rictor-deleted neutrophils because of an improper fusion of granules, reducing the hypochlorous acid production. The loss of Rictor also led to metabolic alterations in isolated neutrophils, increasing aerobic glycolysis. Finally, myeloid-Rictor-deleted mice (LysMRic Δ/Δ) also showed an impairment of the microbicidal capacity, increasing the bacterial burden in the Escherichia coli sepsis model. Overall, our results highlight the importance of proper mTORC2 activation for neutrophil effector functions and metabolism during sepsis.

COVID-19 convalescent plasma cohort study: Evaluation of the association between both donor and recipient neutralizing antibody titers and patient outcomes.

BACKGROUND: Current evidence regarding COVID-19 convalescent plasma (CCP) transfusion practices is limited and heterogeneous. We aimed to determine the impact of the use of CCP transfusion in patients with previous circulating neutralizing antibodies (nAbs) in COVID-19. METHODS: Prospective cohort including 102 patients with COVID-19 transfused with ABO compatible CCP on days 0-2 after enrollment. Clinical status of patients was assessed using the adapted World Health Organization (WHO) ordinal scale on days 0, 5, and 14. The nAbs titration was performed using the cytopathic effect-based virus neutralization test with SARS-CoV-2 (GenBank MT126808.1). The primary outcome was clinical improvement on day 14, defined as a reduction of at least two points on the adapted WHO ordinal scale. Secondary outcomes were the number of intensive care unit (ICU)-free days and the number of invasive mechanical ventilation-free days. RESULTS: Both nAbs of CCP units transfused (p < 0.001) and nAbs of patients before CCP transfusions (p = 0.028) were associated with clinical improvements by day 14. No significant associations between nAbs of patients or CCP units transfused were observed in the number of ICU or mechanical ventilation-free days. Administration of CCP units after 10 days of symptom onset resulted in a decrease in ICU-free days (p < 0.001) and mechanical ventilation-free days (p < 0.001). CONCLUSION: Transfusion of high titer nAbs CCP units may be a determinant in clinical strategies against COVID-19. We consider these data as useful parameters to guide future CCP transfusion practices.

Dramatic Response to Pembrolizumab Monotherapy in a Patient With ARID1A-Mutant Lung Adenocarcinoma: Case Report.

Immunotherapy based on immune checkpoint inhibitors (ICIs) either alone or in combination with platinum-based chemotherapy has dramatically changed the therapeutic scenario in non-small cell lung cancer. However, only a subset of patients derives clinical benefits. Although programmed death-ligand 1 (PD-L1) and tumor mutational burden (TMB) are known to be prognostic and demonstrated utility in selecting patients for immunotherapy response, they are imperfect biomarkers. Recent evidence demonstrates that AT-rich interaction domain 1A (ARID1A) deficiency is associated with high antitumor immunity, mismatch repair and TMB, and thus may potentially contribute as a predictive biomarker for ICIs. We herein describe a 60-year-old woman, former smoker, who was diagnosed with lung adenocarcinoma metastatic to the left adrenal gland, with a PD-L1 expression of 60%. Next-generation sequencing test revealed an ARID1A mutation (F2141fs*59, variant allele frequency = 22.5%), TMB of 92 mut/Mb and stable microsatellite status. Given the high PD-L1 expression, elevated TMB, and ARID1A mutation, the patient started on first-line treatment with pembrolizumab monotherapy, and, 5 months after initiating treatment, presented an expressive reduction of lung lesion and a complete response of the adrenal gland. This case illustrates a dramatic response to ICI monotherapy in a lung cancer patient with ARID1A mutation. Predictive biomarkers for immune checkpoint blockade are of the utmost importance to select the patients who truly benefit from immunotherapy. The combination of biomarkers may be the most effective strategy to improve outcomes with ICIs, and ARID1A status should definitely be taken into account when present.

Revealing the BRD4-NOTCH3 fusion: A novel hill in the cancer landscape.

OBJECTIVES: Gene fusions are becoming more evident in cancer scenario for either being the driver alterations, or for the great therapeutic target potential in many cases. Our aim was to characterize the BRD4-NOTCH3 fusion correlating with clinical features, and to determine the frequency of this fusion in the oncological population. MATERIAL AND METHODS: One patient diagnosed with lung adenocarcinoma at Hospital Sírio-Libanês (Brazil) was included. Foundation Medicine database was searched for all BRD4-NOTCH3 fusions among 233,804 specimens. RESULTS: A 76-year-old male patient was diagnosed with lung adenocarcinoma. Molecular assessments demonstrated negative ALK and EGFR, with PD-L1 expression positive by 60 %. He was treated with first line chemotherapy and second line immunotherapy. Subsequent treatments resume re-exposures to chemotherapy with poor responses. A next-generation sequencing (NGS) based assay was performed in the tumor biopsy, revealing mainly mutation in STK11, microsatellite stability, TMB-intermediate, MYC amplification and a BRD4-NOTCH3 fusion. The breakpoint analysis of this fusion indicates that BRD4 active domains are preserved, suggesting that it maintained DNA binding activity, as well as its capacity to be halt by BET inhibitors. Foundation Medicine database was searched for all BRD4-NOTCH3 fusions among more than 230-thousand specimens and it was found in 87 new cases in a rate of 0.04 % occurrence in solid tumors, predominately in gynecological cancers. The same rate was found when we analyzed a different dataset. CONCLUSION: In conclusion, this is the first report of the BRD4-NOTCH3 gene fusion associated with clinical characterization and, although rare, the occurrence of this fusion is constant in different population. Our data suggest that this fusion has great potential to targeted-therapy.

Case Report: A Severe SARS-CoV-2 Infection in a Teenager With Angelman Syndrome.

Teenagers generally present mild to no symptoms of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. In the present report, we present the case of a 14-year-old boy with Angelman syndrome (AS) who presented with severe COVID-19 symptoms. He spent 20 days in the ICU with elevated inflammatory biomarkers (C-reactive protein and D-dimer) and increased peaks of neutrophil-to-lymphocyte ratio, which is uncommon for teenagers diagnosed with COVID-19. Although he showed physiological instability, he was able to produce neutralizing antibodies, suggesting a functional immune response. The literature concerning the immune response to infections in patients with AS is still poor, and to our knowledge, this was the first report of a patient with AS diagnosed with COVID-19. As such, the present study may alert other patients with AS or other rare diseases that they lack a competent immune response and could suffer severe consequences of SARS-CoV-2 infection.

A longitudinal study of convalescent plasma (CCP) donors and correlation of ABO group, initial neutralizing antibodies (nAb), and body mass index (BMI) with nAb and anti-nucleocapsid (NP) SARS-CoV-2 antibody kinetics: Proposals for better quality of CCP collections.

INTRODUCTION: Little is known about the neutralizing (nAb) and binding antibody kinetics in COVID-19 convalescent plasma donors, especially during the first 100 days after disease onset. MATERIALS AND METHODS: A cohort of previously RT-PCR positive (detected by nasopharyngeal swab during the acute phase), male convalescent patients, all with mild symptoms, were enrolled in serial blood sample collection for a longitudinal nAb titers and anti-nucleocapsid (NP) antibodies (IgM, IgG and IgA) evaluation. NAbs were detected by a cytopathic effect-based virus neutralization test (CPE-based VNT), carried out with SARS-CoV-2 (GenBank: MT350282). RESULTS: A total of 78 male volunteers provided 316 samples, spanning a total of 4820 days of study. Although only 25% of donors kept nAb titers ≥160 within 100 days after the onset of disease, there was >75% probability of sustaining nAb titers ≥160 in volunteers whose initial nAb titer was ≥1280, weight ≥ 90 kg or obese, according to their body mass index (BMI), as evidenced by Kaplan-Meier analysis and Cox hazard regression (all p < .02). There was no correlation between the ABO group, ABO antibody titers and persistent high nAb titers. High IgG anti-NP (S/CO ≥5.0) is a good surrogate for detecting nAb ≥ 160, defined by the ROC curve (sensitivity = 90.5%; CI95%: 84.5%-94.7%). CONCLUSION: Selection of CCP donors for multiple collections based on initial high nAb titers (≥1280) or BMI ≥ 30 kg/m2 provides a simple strategy to achieve higher quality in CCP programs. High IgG anti-NP levels can also be used as surrogate markers for high nAb screening.

Macrophage: A Potential Target on Cartilage Regeneration.

Cartilage lesions and osteoarthritis (OA) presents an ever-increasing clinical and socioeconomic burden. Synovial inflammation and articular inflammatory environment are the key factor for chondrocytes apoptosis and hypertrophy, ectopic bone formation and OA progression. To effectively treat OA, it is critical to develop a drug that skews inflammation toward a pro-chondrogenic microenvironment. In this narrative and critical review, we aim to see the potential use of immune cells modulation or cell therapy as therapeutic alternatives to OA patients. Macrophages are immune cells that are present in synovial lining, with different roles depending on their subtypes. These cells can polarize to pro-inflammatory (M1) and anti-inflammatory (M2) phenotypes, being the latter associated with wound-healing by the production of ARG-1 and pro-chondrogenic cytokines, such as IL-10, IL-1RA, and TGF-b. Emerging evidence reveals that macrophage shift can be determined by several stimuli, apart from the conventional in vitro IL-4, IL-13, and IL-10. Evidences show the potential of physical exercise to induce type 2 response, favoring M2 polarization. Moreover, macrophages in contact with oxLDL have effect on the production of anabolic mediators as TGF-b. In the same direction, type II collagen, that plays a critical role in development and maturation process of chondrocytes, can also induce M2 macrophages, increasing TGF-b. The mTOR pathway activation in macrophages was shown to be able to polarize macrophages in vitro, though further studies are required. The possibility to use mesenchymal stem cells (MSCs) in cartilage restoration have a more concrete literature, besides, MSCs also have the capability to induce M2 macrophages. In the other direction, M1 polarized macrophages inhibit the proliferation and viability of MSCs and impair their ability to immunosuppress the environment, preventing cartilage repair. Therefore, even though MSCs therapeutic researches advances, other sources of M2 polarization are attractive issues, and further studies will contribute to the possibility to manipulate this polarization and to use it as a therapeutic approach in OA patients.

Mesenchymal Stem Cells from Human Exfoliated Deciduous Teeth and the Orbicularis Oris Muscle: How Do They Behave When Exposed to a Proinflammatory Stimulus?

Mesenchymal stem cells (MSCs) have been studied as a promising type of stem cell for use in cell therapies because of their ability to regulate the immune response. Although they are classically isolated from the bone marrow, many studies have sought to isolate MSCs from noninvasive sources. The objective of this study was to evaluate how MSCs isolated from the dental pulp of human exfoliated deciduous teeth (SHED) and fragments of the orbicularis oris muscle (OOMDSCs) behave when treated with an inflammatory IFN-γ stimulus, specifically regarding their proliferative, osteogenic, and immunomodulatory potentials. The results demonstrated that the proliferation of SHED and OOMDSCs was inhibited by the addition of IFN-γ to their culture medium and that treatment with IFN-γ at higher concentrations resulted in a greater inhibition of the proliferation of these cells than treatment with IFN-γ at lower concentrations. SHED and OOMDSCs maintained their osteogenic differentiation potential after stimulation with IFN-γ. Additionally, SHED and OOMDSCs have been shown to have low immunogenicity because they lack expression of HLA-DR and costimulatory molecules such as CD40, CD80, and CD86 before and after IFN-γ treatment. Last, SHED and OOMDSCs expressed the immunoregulatory molecule HLA-G, and the expression of this antigen increased after IFN-γ treatment. In particular, an increase in intracellular HLA-G expression was observed. The results obtained suggest that SHED and OOMDSCs lack immunogenicity and have immunomodulatory properties that are enhanced when they undergo inflammatory stimulation with IFN-γ, which opens new perspectives for the therapeutic use of these cells.

Fecal IgA Levels and Gut Microbiota Composition Are Regulated by Invariant Natural Killer T Cells.

BACKGROUND: The gut microbiota is a key element to support host homeostasis and the development of the immune system. The relationship between the microbiota and immunity is a 2-way road, in which the microbiota contributes to the development/function of immune cells and immunity can affect the composition of microbes. In this context, natural killer T cells (NKT cells) are distinct T lymphocytes that play a role in gut immunity and are influenced by gut microbes. In our work, we investigated the involvement of invariant NKT cells (iNKT) in intestinal homeostasis. RESULTS: We found that iNKT-deficient mice (iNKT-KO) had reduced levels of fecal IgA and an altered composition of the gut microbiota, with increased Bacteroidetes. The absence of iNKT cells also affected TGF-ß1 levels and plasma cells, which were significantly reduced in knockout (KO) mice. In addition, when submitted to dextran sodium sulfate colitis, iNKT-KO mice had worsening of colitis when compared with wild-type (WT) mice. To further address iNKT cell contribution to intestinal homeostasis, we adoptively transferred iNKT cells to KO mice, and they were submitted to colitis. Transfer of iNKT cells improved colitis and restored fecal IgA levels and gut microbiota. CONCLUSIONS: Our results indicate that intestinal NKT cells are important modulators of intestinal homeostasis and that gut microbiota composition may be a potential target in the management of inflammatory bowel diseases.

Cytokine Profile in Early Infection by Leptospira interrogans in A/J Mice.

Leptospirosis is considered a neglected disease with an estimated more than one million cases every year. Since rodents are at the same time the main reservoir and generally asymptomatic to Leptospira infection, understanding why some animal species are resistant and others are susceptible to this infection would shed some light in how to control this important zoonosis. The innate immune response against Leptospira is mainly dependent on phagocytosis and activation of the Complement System. In this context, cytokines may drive the early control of infection and the adaptive response. Since the Complement System is important to eliminate leptospires in vivo, we investigated if Complement C5 in A/J mice would modulate the cytokine production during infection by Leptospira interrogans serovar Kennewicki type Pomona Fromm (LPF). Thus, our aim was to investigate the systemic levels of pro- and anti-inflammatory cytokines during Leptospira infection in the blood, liver, lung, and kidney on the third and sixth days of infection in A/J C5+/+ and A/J C5-/- mice. Blood levels of TNF-α, IL-6, IFN-γ, and MCP-1 reached a peak on the third day. Although both mouse strains developed splenomegaly, similar histopathological alterations in the liver and the lung, levels of pro- and anti-inflammatory cytokines were different. A/J C5+/+ mice had higher levels of liver IL-10, IL-1ß, IL-12p40, and IL-12p70 and kidney IL-1ß, IL-12p40, and IL-12p70 on the sixth day of infection when compared to A/J C5-/- mice. Our results showed that in A/J genetic background, the Complement component C5 modulates a cytokine profile in the liver and kidney of infected mice, which may play a role in the control of disease progression.