Intraspinal administration of human spinal cord-derived neural progenitor cells in the G93A-SOD1 mouse model of ALS delays symptom progression, prolongs survival and increases expression of endogenous neurotrophic factors.

Neural stem or progenitor cells are considered to be a novel therapeutic strategy for amyotrophic lateral sclerosis (ALS), based on their potential to generate a protective environment rather than to replace degenerating motor neurons. Following local injection to the spinal cord, neural progenitor cells may generate glial cells and release neurotrophic factors. In the present study, human spinal cord-derived neural progenitor cells (hscNPCs) were injected into the lumbar spinal cord of G93A-SOD1 ALS transgenic mice. We evaluated the potential effect of hscNPC treatment by survival analysis and behavioural/phenotypic assessments. Immunohistological and real-time PCR experiments were performed at a defined time point to study the underlying mechanisms. Symptom progression in hscNPC-injected mice was significantly delayed at the late stage of disease. On average, survival was only prolonged for 5 days. Animals treated with hscNPCs performed significantly better in motor function tests between weeks 18 and 19. Increased production of GDNF and IGF-1 mRNA was detectable in spinal cord tissue of hscNPC-treated mice. In summary, treatment with hscNPCs led to increased endogenous production of several growth factors and increased the preservation of innervated motor neurons but had only a small effect on overall survival. Copyright © 2015 John Wiley & Sons, Ltd.

Streptococcus pneumoniae triggers progression of pulmonary fibrosis through pneumolysin.

RATIONALE: Respiratory tract infections are common in patients suffering from pulmonary fibrosis. The interplay between bacterial infection and fibrosis is characterised poorly. OBJECTIVES: To assess the effect of Gram-positive bacterial infection on fibrosis exacerbation in mice. METHODS: Fibrosis progression in response to Streptococcus pneumoniae was examined in two different mouse models of pulmonary fibrosis. MEASUREMENTS AND MAIN RESULTS: We demonstrate that wild-type mice exposed to adenoviral vector delivery of active transforming growth factor-ß1 (TGFß1) or diphteria toxin (DT) treatment of transgenic mice expressing the DT receptor (DTR) under control of the surfactant protein C (SPC) promoter (SPC-DTR) to induce pulmonary fibrosis developed progressive fibrosis following infection with Spn, without exhibiting impaired lung protective immunity against Spn. Antibiotic treatment abolished infection-induced fibrosis progression. The cytotoxin pneumolysin (Ply) of Spn caused this phenomenon in a TLR4-independent manner, as Spn lacking Ply (SpnΔply) failed to trigger progressive fibrogenesis, whereas purified recombinant Ply did. Progressive fibrogenesis was also observed in AdTGFß1-exposed Ply-challenged TLR4 KO mice. Increased apoptotic cell death of alveolar epithelial cells along with an attenuated intrapulmonary release of antifibrogenic prostaglandin E2 was found to underlie progressive fibrogenesis in Ply-challenged AdTGFß1-exposed mice. Importantly, vaccination of mice with the non-cytotoxic Ply derivative B (PdB) substantially attenuated Ply-induced progression of lung fibrosis in AdTGFß1-exposed mice. CONCLUSIONS: Our data unravel a novel mechanism by which infection with Spn through Ply release induces progression of established lung fibrosis, which can be attenuated by protein-based vaccination of mice.

Macrophage-inducible C-type lectin Mincle-expressing dendritic cells contribute to control of splenic Mycobacterium bovis BCG infection in mice.

The macrophage-inducible C-type lectin Mincle has recently been identified to be a pattern recognition receptor sensing mycobacterial infection via recognition of the mycobacterial cell wall component trehalose-6',6-dimycolate (TDM). However, its role in systemic mycobacterial infections has not been examined so far. Mincle-knockout (KO) mice were infected intravenously with Mycobacterium bovis BCG to mimic the systemic spread of mycobacteria under defined experimental conditions. After intravenous infection with M. bovis BCG, Mincle-KO mice responded with significantly higher numbers of mycobacterial CFU in spleen and liver, while reduced granuloma formation was observed only in the spleen. At the same time, reduced Th1 cytokine production and decreased numbers of gamma interferon-producing T cells were observed in the spleens of Mincle-KO mice relative to the numbers in the spleens of wild-type (WT) mice. The effect of adoptive transfer of defined WT leukocyte subsets generated from bone marrow cells of zDC(+/DTR) mice (which bear the human diphtheria toxin receptor [DTR] under the control of the classical dendritic cell-specific zinc finger transcription factor zDC) to specifically deplete Mincle-expressing classical dendritic cells (cDCs) but not macrophages after diphtheria toxin application on the numbers of splenic and hepatic CFU and T cell subsets was then determined. Adoptive transfer experiments revealed that Mincle-expressing splenic cDCs rather than Mincle-expressing macrophages contributed to the reconstitution of attenuated splenic antimycobacterial immune responses in Mincle-KO mice after intravenous challenge with BCG. Collectively, we show that expression of Mincle, particularly by cDCs, contributes to the control of splenic M. bovis BCG infection in mice.

Altered expression of DJ-1 and PINK1 in sporadic ALS and in the SOD1(G93A) ALS mouse model.

Mitochondrial dysfunction is an important mechanism in the pathogenesis of neurodegenerative diseases such as Parkinson disease and amyotrophic lateral sclerosis (ALS). DJ-1 and PTEN-induced putative kinase 1 (PINK1) are important proteins for the maintenance of mitochondrial function and protection against cell death. Mutations in the genes coding for these proteins cause familial forms of Parkinson disease. Recent studies have postulated that changes in the expression of both proteins are also involved in pathologic mechanisms in ALS mouse models. Here, we studied the mRNA and protein expression of PINK1 and DJ-1 in postmortem brain and spinal cord tissue and muscle biopsy samples from ALS patients and controls and in brain, spinal cord, and gastrocnemius muscle of SOD1(G93A) ALS mice at different disease stages. We found significant decreases of PINK1 and DJ-1 mRNA levels in muscle tissue of SOD1(G93A) mice. Together with the significant decrease of PINK1 mRNA levels in human ALS muscle tissue, statistically nonsignificant reduction of DJ-1 mRNA levels, and reduced immunostaining for PINK1 in human ALS muscle, the results suggest potential pathophysiologic roles for these proteins in both mutant SOD1 transgenic mice and in sporadic ALS(G93A).

Neural progenitors derived from human induced pluripotent stem cells survive and differentiate upon transplantation into a rat model of amyotrophic lateral sclerosis.

Human induced pluripotent stem cells (iPSCs) offer hope for personalized regenerative cell therapy in amyotrophic lateral sclerosis (ALS). We analyzed the fate of human iPSC-derived neural progenitors transplanted into the spinal cord of wild-type and transgenic rats carrying a human mutated SOD1(G93A) gene. The aim was to follow survival and differentiation of human neural progenitors until day 60 post-transplantation in two different in vivo environments, one being ALS-like. iPSC-derived neural progenitors efficiently engrafted in the adult spinal cord and survived at high numbers. Different neural progenitor, astroglial, and neuronal markers indicated that, over time, the transplanted nestin-positive cells differentiated into cells displaying a neuronal phenotype in both wild-type and transgenic SOD1 rats. Although a transient microglial phenotype was detected at day 15, astroglial staining was negative in engrafted cells from day 1 to day 60. At day 30, differentiation toward a neuronal phenotype was identified, which was further established at day 60 by the expression of the neuronal marker MAP2. A specification process into motoneuron-like structures was evidenced in the ventral horns in both wild-type and SOD1 rats. Our results demonstrate proof-of-principle of survival and differentiation of human iPSC-derived neural progenitors in in vivo ALS environment, offering perspectives for the use of iPSC-based therapy in ALS.

Intracerebroventricular injection of encapsulated human mesenchymal cells producing glucagon-like peptide 1 prolongs survival in a mouse model of ALS.

BACKGROUND: As pharmacological therapies have largely failed so far, stem cell therapy has recently come into the focus of ALS research. Neuroprotective potential was shown for several types of stem and progenitor cells, mainly due to release of trophic factors. In the present study, we assessed the effects of intracerebroventricular injection of glucagon-like peptide 1 (GLP-1) releasing mesenchymal stromal cells (MSC) in mutant SOD1 (G93A) transgenic mice. METHODOLOGY/PRINCIPAL FINDINGS: To improve the neuroprotective effects of native MSC, they had been transfected with a plasmid vector encoding a GLP-1 fusion gene prior to the injection, as GLP-1 was shown to exhibit neuroprotective properties before. Cells were encapsulated and therefore protected against rejection. After intracerebroventricular injection of these GLP-1 MSC capsules in presymptomatic SOD1 (G93A) mice, we assessed possible protective effects by survival analysis, measurement of body weight, daily monitoring and evaluation of motor performance by rotarod and footprint analyses. Motor neuron numbers in the spinal cord as well as the amount of astrocytosis, microglial activation, heat shock response and neuronal nitric oxide synthase (nNOS) expression were analyzed by immunohistological methods. Treatment with GLP-1 producing MSC capsules significantly prolonged survival by 13 days, delayed symptom onset by 15 days and weight loss by 14 days and led to significant improvements in motor performance tests compared to vehicle treated controls. Histological data are mainly in favour of anti-inflammatory effects of GLP-1 producing MSC capsules with reduced detection of inflammatory markers and a significant heat shock protein increase. CONCLUSION/SIGNIFICANCE: Intracerebroventricular injection of GLP-1 MSC capsules shows neuroprotective potential in the SOD1 (G93A) mouse model.