Newer generations of multi-target CAR and STAb-T immunotherapeutics: NEXT CART Consortium as a cooperative effort to overcome current limitations

Adoptive T cellular immunotherapies have emerged as relevant approaches for treating cancer patients who have relapsed or become refractory (R/R) to traditional cancer treatments. Chimeric antigen receptor (CAR) T-cell therapy has improved survival in various hematological malignancies. However, significant limitations still impede the widespread adoption of these therapies in most cancers. To advance in this field, six research groups have created the "NEXT Generation CART MAD Consortium" (NEXT CART) in Madrid's Community, which aims to develop novel cell-based immunotherapies for R/R and poor prognosis cancers. At NEXT CART, various basic and translational research groups and hospitals in Madrid concur to share and synergize their basic expertise in immunotherapy, gene therapy, and immunological synapse, and clinical expertise in pediatric and adult oncology. NEXT CART goal is to develop new cell engineering approaches and treatments for R/R adult and pediatric neoplasms to evaluate in multicenter clinical trials. Here, we discuss the current limitations of T cell-based therapies and introduce our perspective on future developments. Advancement opportunities include developing allogeneic products, optimizing CAR signaling domains, combining cellular immunotherapies, multi-targeting strategies, and improving tumor-infiltrating lymphocytes (TILs)/T cell receptor (TCR) therapy. Furthermore, basic studies aim to identify novel tumor targets, tumor molecules in the tumor microenvironment that impact CAR efficacy, and strategies to enhance the efficiency of the immunological synapse between immune and tumor cells. Our perspective of current cellular immunotherapy underscores the potential of these treatments while acknowledging the existing hurdles that demand innovative solutions to develop their potential for cancer treatment fully.

Choosing T-cell sources determines CAR-T cell activity in neuroblastoma

Introduction

The clinical success of chimeric antigen receptor-modified T cells (CAR-T cells) for hematological malignancies has not been reproduced for solid tumors, partly due to the lack of cancer-type specific antigens. In this work, we used a novel combinatorial approach consisting of a versatile anti-FITC CAR-T effector cells plus an FITC-conjugated neuroblastoma (NB)-targeting linker, an FITC-conjugated monoclonal antibody (Dinutuximab) that recognizes GD2.

Methods

We compared cord blood (CB), and CD45RA-enriched peripheral blood leukapheresis product (45RA) as allogeneic sources of T cells, using peripheral blood (PB) as a control to choose the best condition for anti-FITC CAR-T production. Cells were manufactured under two cytokine conditions (IL-2 versus IL-7+IL-15+IL-21) with or without CD3/CD28 stimulation. Immune phenotype, vector copy number, and genomic integrity of the final products were determined for cell characterization and quality control assessment. Functionality and antitumor capacity of CB/45RA-derived anti-FITC CAR-T cells were analyzed in co-culture with different anti-GD2-FITC labeled NB cell lines.

Results

The IL-7+IL-15+IL-21 cocktail, in addition to co-stimulation signals, resulted in a favorable cell proliferation rate and maintained less differentiated immune phenotypes in both CB and 45RA T cells. Therefore, it was used for CAR-T cell manufacturing and further characterization. CB and CD45RA-derived anti-FITC CAR-T cells cultured with IL-7+IL-15+IL-21 retained a predominantly naïve phenotype compared with controls. In the presence of the NB-FITC targeting, CD4+ CB-derived anti-FITC CAR-T cells showed the highest values of co-stimulatory receptors OX40 and 4-1BB, and CD8+ CAR-T cells exhibited high levels of PD-1 and 4-1BB and low levels of TIM3 and OX40, compared with CAR-T cells form the other sources studied. CB-derived anti-FITC CAR-T cells released the highest amounts of cytokines (IFN-γ and TNF-α) into co-culture supernatants. The viability of NB target cells decreased to 30% when co-cultured with CB-derived CAR-T cells during 48h.

Conclusion

CB and 45RA-derived T cells may be used as allogeneic sources of T cells to produce CAR-T cells. Moreover, ex vivo culture with IL-7+IL-15+IL-21 could favor CAR-T products with a longer persistence in the host. Our strategy may complement the current use of Dinutuximab in treating NB through its combination with a targeted CAR-T cell approach.

3D environment controls H3K4 methylation and the mechanical response of the nucleus in acute lymphoblastic leukemia cells

Acute lymphoblastic leukemia (ALL) is the most common pediatric cancer, and the infiltration of leukemic cells is critical for disease progression and relapse. Nuclear deformability plays a critical role in cancer cell invasion through confined spaces; however, the direct impact of epigenetic changes on the nuclear deformability of leukemic cells remains unclear. Here, we characterized how 3D collagen matrix conditions induced H3K4 methylation in ALL cell lines and clinical samples. We used specific shRNA and chemical inhibitors to target WDR5 (a core subunit involved in H3K4 methylation) and determined that targeting WDR5 reduced the H3K4 methylation induced by the 3D environment and the invasiveness of ALL cells in vitro and in vivo. Intriguingly, targeting WDR5 did not reduce the adhesion or the chemotactic response of leukemia cells, suggesting a different mechanism by which H3K4 methylation might govern ALL cell invasiveness. Finally, we conducted biochemical, and biophysical experiments to determine that 3D environments promoted the alteration of the chromatin, the morphology, and the mechanical behavior of the nucleus in ALL cells. Collectively, our data suggest that 3D environments control an upregulation of H3K4 methylation in ALL cells, and targeting WDR5 might serve as a promising therapeutic target against ALL invasiveness in vivo.

Immune stress suppresses innate immune signaling in preleukemic precursor B-cells to provoke leukemia in predisposed mice

The initial steps of B-cell acute lymphoblastic leukemia (B-ALL) development usually pass unnoticed in children. Several preclinical studies have shown that exposure to immune stressors triggers the transformation of preleukemic B cells to full-blown B-ALL, but how this takes place is still a longstanding and unsolved challenge. Here we show that dysregulation of innate immunity plays a driving role in the clonal evolution of pre-malignant Pax5+/- B-cell precursors toward leukemia. Transcriptional profiling reveals that Myd88 is downregulated in immune-stressed pre-malignant B-cell precursors and in leukemic cells. Genetic reduction of Myd88 expression leads to a significant increase in leukemia incidence in Pax5+/-Myd88+/- mice through an inflammation-dependent mechanism. Early induction of Myd88-independent Toll-like receptor 3 signaling results in a significant delay of leukemia development in Pax5+/- mice. Altogether, these findings identify a role for innate immunity dysregulation in leukemia, with important implications for understanding and therapeutic targeting of the preleukemic state in children.

Intraosseous injection of mesenchymal stem cells for the treatment of osteonecrosis of the immature femoral head and prevention of head deformity: A study in a pig model

BACKGROUND

Cell therapy has been proposed as part of the therapeutic arsenal to assist bone formation and remodeling in the early stages of osteonecrosis of the femoral head. The purpose of this study is to determine the effects of intraosseous inoculation of mesenchymal stem cells on bone formation and remodeling in an established experimental model of osteonecrosis of the femoral head in immature pigs.

METHODS

Thirty-one 4-week-old immature Yorkshire pigs were used. Experimental osteonecrosis of the femoral head was created in the right hip of all included animals (n  =  31). The month after surgery, hip and pelvis radiographs were taken to confirm osteonecrosis of the femoral head. Four animals were excluded following surgery. Two groups were established: (A) mesenchymal stem cell-treated group (n  =  13) and (B) saline-treated group (n  =  14). One month after surgery the mesenchymal stem cell-group received an intraosseous injection of 10  ×  106 mesenchymal stem cell (5 cc) and the saline-treated group of 5 cc of physiological saline solution. Osteonecrosis of the femoral head progression was assessed by monthly X-rays (1-, 2-, 3- and 4-months post-surgery). The animals were sacrificed 1 or 3 months following the intraosseous injection. Repair tissue and osteonecrosis of the femoral head were histologically evaluated immediately after sacrifice.

RESULTS

At time of sacrifice, radiographic images showed evident osteonecrosis of the femoral head with associated severe femoral head deformity in 11 of the 14 animals (78%) in the saline group and in only 2 of the 13 animals (15%) in the mesenchymal stem cell group. Histologically, the mesenchymal stem cell group showed less osteonecrosis of the femoral head and less flattening. In the saline group, there was pronounced femoral head flattening and the damaged epiphyseal trabecular bone was largely replaced with fibrovascular tissue.

CONCLUSION

Intraosseous mesenchymal stem cells inoculation improved bone healing and remodeling in our immature pig osteonecrosis of the femoral head model. This work supports further investigation to determine whether mesenchymal stem cells enhance the healing process in immature osteonecrosis of the femoral head.

IgG antispike persistence and immunophenotype in children infected by SARS-CoV-2

AIM

The immune status of children recovering from SARS-CoV-2 infection is not completely understood. We describe IgG antispike persistence in children infected during the first two pandemic waves. In addition, we compared with healthy controls their leukocyte populations and CD64 expression.

METHODS

Cross-sectional study. Carried out from October 2021 to February 2022 in nonreinfected and nonvaccinated children with SARS-CoV-2 in 2020. The presence of antispike IgG was studied using chemiluminescent immunoassay. Leukocyte populations were analysed using flow cytometry and marked for CD45, CD4, CD8 and CD64. Statistical minor than 0.05 was considered significant.

RESULTS

One hundred and eighty-three control and 77 patients were included. IgG antispike determinations were performed after a median of 501 days (262-464); 52 of 77 children were positive. Cases showed significantly higher percentages of monocytes, lymphocytes, CD8⁺ and CD4⁺ . In addition, CD64 expression was higher in monocytes and neutrophils. The presence of IgG antispike was accompanied by a higher percentage of CD64⁺ neutrophils.

CONCLUSION

In our series, the SARS-CoV-2 IgG antispike protein was usually positive beyond 1 year after infection. Furthermore, leukocyte populations from cases differ from controls, with higher CD64 expression on neutrophils and monocytes. Prospective clinical observations are required to confirm the implications of these findings.

Combined exercise intervention in a mouse model of high-risk neuroblastoma: effects on physical, immune, tumor and clinical outcomes

Background

Exercise might exert anti-tumoral effects in adult cancers but this question remains open in pediatric tumors, which frequently show a different biology compared to adult malignancies. We studied the effects of an exercise intervention on physical function, immune variables and tumoral response in a preclinical model of a highly aggressive pediatric cancer, high-risk neuroblastoma (HR-NB).

Methods

6-8-week-old male mice with orthotopically-induced HR-NB were assigned to a control (N = 13) or exercise (5-week combined [aerobic+resistance]) group (N = 17). Outcomes included physical function (cardiorespiratory fitness [CRF] and muscle strength), as well as related muscle molecular indicators, blood and tumor immune cell and molecular variables, tumor progression, clinical severity, and survival.

Results

Exercise attenuated CRF decline (p=0.029 for the group-by-time interaction effect), which was accompanied by higher muscle levels of oxidative capacity (citrate synthase and respiratory chain complexes III, IV and V) and an indicator of antioxidant defense (glutathione reductase) in the intervention arm (all p≤0.001), as well as by higher levels of apoptosis (caspase-3, p=0.029) and angiogenesis (vascular endothelial growth factor receptor-2, p=0.012). The proportion of 'hot-like' (i.e., with viable immune infiltrates in flow cytometry analyses) tumors tended to be higher (p=0.0789) in the exercise group (76.9%, vs. 33.3% in control mice). Exercise also promoted greater total immune (p=0.045) and myeloid cell (p=0.049) infiltration within the 'hot' tumors, with a higher proportion of two myeloid cell subsets (CD11C+ [dendritic] cells [p=0.049] and M2-like tumor-associated macrophages [p=0.028]), yet with no significant changes in lymphoid infiltrates or in cirulating immune cells or chemokines/cytokines. No training effect was found either for muscle strength or anabolic status, cancer progression (tumor weight and metastasis, tumor microenvironment), clinical severity, or survival.

Conclusions

Combined exercise appears as an effective strategy for attenuating physical function decline in a mouse model of HR-NB, also exerting some potential immune benefits within the tumor, which seem overall different from those previously reported in adult cancers.

Transient Inhibition of the JAK/STAT Pathway Prevents B-ALL Development in Genetically Predisposed Mice

Preventing development of childhood B-cell acute lymphoblastic leukemia (B-ALL), a disease with devastating effects, is a longstanding and unsolved challenge. Heterozygous germline alterations in the PAX5 gene can lead to B-ALL upon accumulation of secondary mutations affecting the JAK/STAT signaling pathway. Preclinical studies have shown that this malignant transformation occurs only under immune stress such as exposure to infectious pathogens. Here we show in Pax5+/- mice that transient, early-life administration of clinically relevant doses of ruxolitinib, a JAK1/2 inhibitor, significantly mitigates the risk of B-ALL following exposure to infection; 1 of 29 animals treated with ruxolitinib developed B-ALL versus 8 of 34 untreated mice. Ruxolitinib treatment preferentially targeted Pax5+/- versus wild-type B-cell progenitors and exerted unique effects on the Pax5+/- B-cell progenitor transcriptional program. These findings provide the first in vivo evidence for a potential strategy to prevent B-ALL development.

SIGNIFICANCE

JAK/STAT inhibition suppresses tumorigenesis in a B-ALL-susceptible mouse model, presenting a novel approach to prevent B-ALL onset.

Increased Hypothalamic Anti-Inflammatory Mediators in Non-Diabetic Insulin Receptor Substrate 2-Deficient Mice

Insulin receptor substrate (IRS) 2 is a key mediator of insulin signaling and IRS-2 knockout (IRS2^−/−) mice are a preclinical model to study the development of diabetes, as they develop peripheral insulin resistance and beta-cell failure. The differential inflammatory profile and insulin signaling in the hypothalamus of non-diabetic (ND) and diabetic (D) IRS2^−/− mice might be implicated in the onset of diabetes. Because the lipid profile is related to changes in inflammation and insulin sensitivity, we analyzed whether ND IRS2^−/− mice presented a different hypothalamic fatty acid metabolism and lipid pattern than D IRS2^−/− mice and the relationship with inflammation and markers of insulin sensitivity. ND IRS2^−/− mice showed elevated hypothalamic anti-inflammatory cytokines, while D IRS2^−/− mice displayed a proinflammatory profile. The increased activity of enzymes related to the pentose-phosphate route and lipid anabolism and elevated polyunsaturated fatty acid levels were found in the hypothalamus of ND IRS2^−/− mice. Conversely, D IRS2^−/− mice have no changes in fatty acid composition, but hypothalamic energy balance and markers related to anti-inflammatory and insulin-sensitizing properties were reduced. The data suggest that the concurrence of an anti-inflammatory profile, increased insulin sensitivity and polyunsaturated fatty acids content in the hypothalamus may slow down or delay the onset of diabetes.

Characteristics of carrier cells associated with clinical response in children treated with adenoviral virotherapy administered in autologous marrow-derived mesenchymal cells

e15217

Background: We used oncolytic virotherapy carried by autologous marrow-derived mesenchymal cells to treat children with metastatic/refractory tumors (NCT01844661; 10.1016/j.ymthe.2020.01.019 and 10.1016/j.canlet.2015.11.036). Most patients did not show clinical response while a small group did. Methods: We have carried out a comprehensive study of the transcriptome of this new advanced therapy medicine (ATM) to find determinants that might be associated with clinical outcome. Results: The study of the ATM's transcriptome from a first cohort of patients identified signatures associated to biological processes in the infected carrier cells that distinguished responders from non-responders (viral infection and nucleic acid metabolism; immune regulatory routes; cell-cell adhesion; mitosis; cell metabolism; response to stress; and bone marrow fibrosis). Next, we used an approach based on systems biology and neural networks to identify candidates responsible for the differences found in gene expression signatures. We then validated the identified candidates using samples obtained from a second independent cohort of patients, by quantitative PCR and ELISA. Mesenchymal cells of the responding patients expressed significantly lower levels of the MAVS and NDRG1 genes compared with those of the non-responders after oncolytic adenoviral infection. Both genes are related to cellular antiviral responses and cellular metabolism. Accordingly, mesenchymal cells of responders produced significantly lower amounts of IL-6 and CCL-2 than non-responders’ cells. Conclusions: These results point to possible pretreatment biomarkers and the possibility of optimizing a universal version of the carrier cells for the oncolytic virus in this new ATM.

Genetic and Immune Changes Associated with Disease Progression under the Pressure of Oncolytic Therapy in A Neuroblastoma Outlier Patient

Little is known about the effect of oncolytic adenovirotherapy on pediatric tumors. Here we present the clinical case of a refractory neuroblastoma that responded positively to Celyvir (ICOVIR-5 oncolytic adenovirus delivered by autologous mesenchymal stem cells) for several months. We analyzed samples during tumor evolution in order to identify molecular and mutational features that could explain the interactions between treatment and tumor and how the balance between both of them evolved. We identified a higher adaptive immune infiltration during stabilized disease compared to progression, and also a higher mutational rate and T-cell receptor (TCR) diversity during disease progression. Our results indicate an initial active role of the immune system controlling tumor growth during Celyvir therapy. The tumor eventually escaped from the control exerted by virotherapy through acquisition of resistance by the tumor microenvironment that exhausted the initial T cell response.

Systemic oncolytic adenovirus delivered in mesenchymal carrier cells modulate tumor infiltrating immune cells and tumor microenvironment in mice with neuroblastoma

Celyvir (autologous mesenchymal cells -MSCs- that carry an oncolytic adenovirus) is a new therapeutic strategy for metastatic tumors developed by our research group over the last decade. There are limitations for studying the immune effects of human oncolytic adenoviruses in murine models since these viruses do not replicate naturally in these animals. The use of xenografts in immunodeficient mice prevent assessing important clinical aspects of this therapy such as the antiadenoviral immune response or the possible intratumoral immune changes, both of tumor infiltrating leukocytes and of the microenvironment. In our strategy, the presence of MSCs in the medicinal product adds an extra level of complexity. We present here a murine model that overcomes many of these limitations. We found that carrier cells outcompeted intravenous administration of naked particles in delivering the oncolytic virus into the tumor masses. The protection that MSCs could provide to the oncolytic adenovirus did not preclude the development of an antiadenoviral immune response. However, the presence of circulating antiadenoviral antibodies did not prevent changes detected at the tumor masses: increased infiltration and changes in the quality of immune cells per unit of tumor volume, and a less protumoral and more inflammatory profile of the tumor microenvironment. We believe that the model described here will enable the study of crucial events related to the immune responses affecting both the medicinal product and the tumor.

First-in-Human, First-in-Child Trial of Autologous MSCs Carrying the Oncolytic Virus Icovir-5 in Patients with Advanced Tumors

We present here the results of a first-in-human, first-in-child trial for patients with relapsed/refractory solid tumors using Celyvir, an advanced therapy medicine that combines autologous mesenchymal stem cells (MSCs) carrying an oncolytic adenovirus. Celyvir was manufactured from a bone marrow aspirate and then given intravenously. Patients received weekly infusions for 6 weeks at a dose of 2 × 10⁶ cells/kg (children) or 0.5-1 × 10⁶ cells/kg (adults), 2 × 10⁴ viral particles per cell. Fifteen pediatric and 19 adult patients were recruited, but 18 were screen failures, mainly because rapid disease progression before Celyvir was available. No grade 2-5 toxicities were reported. Adenoviral replication detected by PCR was found in all but 2 pediatric patient and in none of the adult ones. Absolute numbers of circulating leukocytes suffered minor changes along therapy, but some subsets showed differences comparing the pediatric versus the adult cohorts. Two patients with neuroblastoma showed disease stabilization, and one of them continued on treatment for up to 6 additional weeks. Celyvir, the combination of MSCs and oncolytic adenovirus, is safe and warrants further evaluation in a phase 2 setting. The use of MSCs may be a strategy to increase the amount of oncolytic virus administered to patients, minimizing toxicities and avoiding direct tumor injections.

Benefits of exercise and immunotherapy in a murine model of human non-small-cell lung carcinoma

BACKGROUND

Lung cancer has the highest incidence and mortality rate in the world. One of the most promising new cancer therapies in recent years is immunotherapy, which is based on the blockade of immune checkpoints such as programmed cell death protein 1 (PD-1). Exercise training is beneficial to maintain and improve the quality of life of cancer patients, and it might also modulate the anti-tumoral efficiency of some chemotherapeutic agents. However, the potential of exercise combined with immunotherapy as a cancer therapy remains to be elucidated. Here, we examined the effects of exercise on tumor growth and its possible adjuvant effects when combined with anti-PD-1 immunotherapy (nivolumab) in a patient derived xenograft (PDX) model of non-small-cell lung carcinoma (NSCLC).

METHODS

We generated a PDX model using NOD-SCID gamma mice with subcutaneous grafts from tumor tissue of a patient with NSCLC. Animals were randomly assigned to one of four groups: non-exercise + isotype control (n=5), exercise + isotype control (n=5), non-exercise + nivolumab (n=6) or exercise + nivolumab (n=6). The animals undertook an 8- week moderate-intensity training regimen (treadmill aerobic exercise and strength training). Immunotherapy (nivolumab) or an isotype control was administered 2 days/week, for 6 weeks. Several tumor growth and microenvironment parameters were measured after the intervention.

RESULTS

Improvements in aerobic capacity and muscle strength (p=0.027 and p=0.005) were noted in exercised animals. Exercise alone reduced the tumor growth rate with respect to non-exercised mice (p=0.050). The double intervention (exercise + nivolumab) increased tumor necrosis and reduced apoptosis with respect to controls (p=0.026; p=0.030). All interventions achieved a reduction in proliferation compared with the control group (p=0.015, p=0.011, and p=0.011). Exercise alone increased myeloid tumor infiltrates (mostly neutrophils) with respect to the nivolumab only group (p=0.018). Finally, Vegf-a expression was higher in the nivolumab groups (in combination or not with exercise) than in exercise + isotype control group (p=0.045 and p=0.047, respectively). No other significant effects were found.

CONCLUSIONS

Our results would suggest that aerobic and strength training should be studied as an adjuvant to cancer immunotherapy treatment.

Muscle molecular adaptations to endurance exercise training are conditioned by glycogen availability: a proteomics-based analysis in the McArdle mouse model

KEY POINTS

Although they are unable to utilize muscle glycogen, McArdle mice adapt favourably to an individualized moderate-intensity endurance exercise training regime. Yet, they fail to reach the performance capacity of healthy mice with normal glycogen availability. There is a remarkable difference in the protein networks involved in muscle tissue adaptations to endurance exercise training in mice with and without glycogen availability. Indeed, endurance exercise training promoted the expression of only three proteins common to both McArdle and wild-type mice: LIMCH1, PARP1 and TIGD4. In turn, trained McArdle mice presented strong expression of mitogen-activated protein kinase 12 (MAPK12).

ABSTRACT

McArdle's disease is an inborn disorder of skeletal muscle glycogen metabolism that results in blockade of glycogen breakdown due to mutations in the myophosphorylase gene. We recently developed a mouse model carrying the homozygous p.R50X common human mutation (McArdle mouse), facilitating the study of how glycogen availability affects muscle molecular adaptations to endurance exercise training. Using quantitative differential analysis by liquid chromatography with tandem mass spectrometry, we analysed the quadriceps muscle proteome of 16-week-old McArdle (n = 5) and wild-type (WT) (n = 4) mice previously subjected to 8 weeks' moderate-intensity treadmill training or to an equivalent control (no training) period. Protein networks enriched within the differentially expressed proteins with training in WT and McArdle mice were assessed by hypergeometric enrichment analysis. Whereas endurance exercise training improved the estimated maximal aerobic capacity of both WT and McArdle mice as compared with controls, it was ∼50% lower than normal in McArdle mice before and after training. We found a remarkable difference in the protein networks involved in muscle tissue adaptations induced by endurance exercise training with and without glycogen availability, and training induced the expression of only three proteins common to McArdle and WT mice: LIM and calponin homology domains-containing protein 1 (LIMCH1), poly (ADP-ribose) polymerase 1 (PARP1 - although the training effect was more marked in McArdle mice), and tigger transposable element derived 4 (TIGD4). Trained McArdle mice presented strong expression of mitogen-activated protein kinase 12 (MAPK12). Through an in-depth proteomic analysis, we provide mechanistic insight into how glycogen availability affects muscle protein signalling adaptations to endurance exercise training.

Patient-derived mesenchymal stem cells as delivery vehicles for oncolytic virotherapy: novel state-of-the-art technology

Oncolytic virotherapy is gaining interest in the clinic as a new weapon against cancer. In vivo administration of oncolytic viruses showed important limitations that decrease their effectiveness very significantly: the antiviral immune response causes the elimination of the therapeutic effect, and the poor natural ability of oncolytic viruses to infect micrometastatic lesions significantly minimizes the effective dose of virus. This review will focus on updating the technical and scientific foundations of one of the strategies developed to overcome these limitations, ie, using cells as vehicles for oncolytic viruses. Among many candidates, a special type of adult stem cell, mesenchymal stem cells (MSCs), have already been used in the clinic as cell vehicles for oncolytic viruses, partly due to the fact that these cells are actively being evaluated for other indications. MSC carrier cells are used as Trojan horses loaded with oncoviruses, are administered systemically, and release their cargos at the right places. MSCs are equipped with an array of molecules involved in cell arrest in the capillaries (integrins and selectins), migration toward specific parenchymal locations within tissues (chemokine receptors), and invasion and degradation of the extracellular matrix (proteases). In addition to anatomical targeting capacity, MSCs have a well-recognized role in modulating immune responses by affecting cells of the innate (antigen-presenting cells, natural killer cells) and adaptive immune system (effector and regulatory lymphocytes). Therefore, carrier MSCs may also modulate the immune responses taking place after therapy, ie, the antiviral and the antitumor immune responses.

The NFKB Inducing Kinase Modulates Hematopoiesis During Stress

The genetic programs that maintain hematopoiesis during steady state in physiologic conditions are different from those activated during stress. Here, we show that hematopoietic stem cells (HSCs) with deficiencies in components of the alternative NFκB pathway (the NFκB inducing kinase, NIK, and the downstream molecule NFκB2) had a defect in response to stressors such as supraphysiological doses of cytokines, chemotherapy, and hematopoietic transplantation. NIK-deficient mice had peripheral blood and bone marrow leukocyte numbers within normal ranges (except for the already reported defects in B-cell maturation); however, HSCs showed significantly slower expansion capacity in in vitro cultures compared to wild-type HSCs. This was due to a delayed cell cycle and increased apoptosis. In vivo experiments showed that NIK-deficient HSCs did not recover at the same pace as controls when challenged with myeloablative chemotherapy. Finally, NIK-deficient HSCs showed a significantly decreased competitive repopulation capacity in vivo. Using HSCs from mice deficient in one of two downstream targets of NIK, that is, either NFκB2 or c-Rel, only NFκB2 deficiency recapitulated the defects detected with NIK-deficient HSCs. Our results underscore the role of NIK and the alternative NFκB pathway for the recovery of normal levels of hematopoiesis after stress.

Effects of local administration of allogenic adipose tissue-derived mesenchymal stem cells on functional recovery in experimental traumatic brain injury

OBJECTIVE

Traumatic brain injury (TBI) is the leading cause of mortality and morbidity in paediatric patients after the first year of life. The aim of this study was to evaluate effects of locally administered allogeneic mesenchymal stem cells (MSC), in the acute period after a TBI.

METHODOLOGY

MSC were isolated from peritoneal fat of healthy rats, expanded in vitro and labelled with the green fluorescent protein. Rats were placed in one of three experimental groups: (1) CONTROL: TBI, (2) IP-CONTROL: TBI + local saline and (3) IP-Treat: TBI + 2 × 10(5) MSC 24 hours after receiving a moderate, unilateral, controlled cortical impact. Motor and cognitive behavioural tests were performed to evaluate functional recovery. Histological examination and immunohistochemistry were used to identify cell distribution.

MAIN RESULTS

Improved performance was found on motor tests in the MSC-treated group compared to control groups. MSC were found in the perilesional area and their number decreased with time after transplantation. MSC treatment increased the cell density in the hippocampus (CA3 pyramidal cells and granule cells in the dentate gyrus) and enhanced neurogenesis in this area.

CONCLUSION

MSC cell therapy resulted in better recovery of motor function compared with the control group. This cellular therapy might be considered for patients suffering from TBI.

Exercise training can induce cardiac autophagy at end-stage chronic conditions: insights from a graft-versus-host-disease mouse model

INTRODUCTION

Chronic graft-versus-host disease (cGVHD) is a frequent cause of morbimortality after allogeneic hematopoietic stem cell transplantation (allo-HSCT), and severely compromises patients' physical capacity. Despite the aggressive nature of the disease, aerobic exercise training can positively impact survival as well as clinical and functional parameters. We analyzed potential mechanisms underlying the recently reported cardiac function improvement in an exercise-trained cGVHD murine model receiving lethal total body irradiation and immunosuppressant treatment (Fiuza-Luces et al., 2013. Med Sci Sports Exerc 45, 1703-1711). We hypothesized that a cellular quality-control mechanism that is receiving growing attention in biomedicine, autophagy, was involved in such improvement.

METHODS

BALB/C female mice (aged 8wk) with cGVHD were randomly assigned to a control/exercise group (n=12/11); the exercise group underwent moderate-intensity treadmill training during 11wk after allo-HSCT. In the hearts of those few mice surviving the entire 11wk period (n=2/5), we studied molecular markers of: macroautophagy induction, preservation of contractile/structural proteins, oxidative capacity, oxidative stress, antioxidant defense, and mitochondrial dynamics.

RESULTS

Mainly, exercise training increased the myocardial content of the macroautophagy markers LC3BII, Atg12, SQSTM1/p62 and phospho-ULK1 (S555), as well as of α-tubuline, catalase and glutathione reductase (all p<0.05).

CONCLUSIONS

Our results suggest that exercise training elicits a positive autophagic adaptation in the myocardium that may help preserve cardiac function even at the end-stage of a devastating disease like cGVHD. These preliminary findings might provide new insights into the cardiac exercise benefits in chronic/debilitating conditions.