Search

Alcohol use disorder (AUD) is a chronic, relapsing disorder, characterized by escalating alcohol drinking and loss of control, with very limited available treatments. We recently reported that the expression of fibroblast growth factor 2 (Fgf2) is increased in the striatum of rodents following long-term excessive alcohol drinking and that the systemic or intra-striatal administration of recombinant FGF2 increases alcohol consumption. Here, we set out to determine whether the endogenous FGF2 plays a role in alcohol drinking and reward, by testing the behavioural phenotype of Fgf2 knockout mice. We found that Fgf2 deficiency resulted in decreased alcohol consumption when tested in two-bottle choice procedures with various alcohol concentrations. Importantly, these effects were specific for alcohol, as a natural reward (sucrose) or water consumption was not affected by Fgf2 deficiency. In addition, Fgf2 knockout mice failed to show alcohol-conditioned place preference (CPP) but showed normal fear conditioning, suggesting that deletion of the growth factor reduces alcohol's rewarding properties. Finally, Fgf2 knockout mice took longer to recover from the loss of righting reflex and showed higher blood alcohol concentrations when challenged with an intoxicating alcohol dose, suggesting that their ethanol metabolism might be affected. Together, our results show that the endogenous FGF2 plays a critical role in alcohol drinking and reward and indicate that FGF2 is a positive regulator of alcohol-drinking behaviours. Our findings suggest that FGF2 is a potential biomarker for problem alcohol drinking and is a potential target for pharmacotherapy development for AUD.

Cellular therapy represents a novel option for the treatment of neurodegenerative disorders such as amyotrophic lateral sclerosis (ALS). Its major aim is the generation of a protective environment for degenerating motor neurons. Mesenchymal stromal cells secrete different growth factors and have antiapoptotic and immunomodulatory properties. They can easily and safely be isolated from human bone marrow and are therefore considered promising therapeutic candidates. In the present study, we compared intraventricular application of human mesenchymal stromal cells (hMSCs) versus single and repeated intraspinal injections in the mutant SOD1G93A transgenic ALS mouse model. We observed significant reduction of lifespan of animals treated by intraventricular hMSC injection compared with the vehicle treated control group, accompanied by changes in weight, general condition, and behavioural assessments. A potential explanation for these rather surprising deleterious effects lies in increased microgliosis detected in the hMSC treated animals. Repeated intraspinal injection at two time points resulted in a slight but not significant increase in survival and significant improvement of motor performance although no hMSC-induced changes of motor neuron numbers, astrogliosis, and microgliosis were detected. Quantitative real time polymerase chain reaction showed reduced expression of endothelial growth factor in animals having received hMSCs twice compared with the vehicle treated control group. hMSCs were detectable at the injection site at Day 20 after injection into the spinal cord but no longer at Day 70. Intraspinal injection of hMSCs may therefore be a more promising option for the treatment of ALS than intraventricular injection and repeated injections might be necessary to obtain substantial therapeutic benefit.

Amyotrophic Lateral Sclerosis (ALS) is a degenerative motor neuron disorder. It is supposed that ALS is at least in part an axonopathy. Neuropilin 1 is an important receptor of the axon repellent Semaphorin 3A and a co-receptor of vascular endothelial growth factor. It is probably involved in neuronal and axonal de-/regeneration and might be of high relevance for ALS pathogenesis and/or disease progression. To elucidate whether the expression of either Neuropilin1 or Semaphorin3A is altered in ALS we investigated these proteins in human brain, spinal cord and muscle tissue of ALS-patients and controls as well as transgenic SOD1G93A and control mice. Neuropilin1 and Semaphorin3A gene and protein expression were assessed by quantitative real-time PCR (qRT-PCR), western blot and immunohistochemistry. Groups were compared using either Student t-test or Mann-Whitney U test. We observed a consistent increase of Neuropilin1 expression in the spinal cord and decrease of Neuropilin1 and Semaphorin3A in muscle tissue of transgenic SOD1G93A mice at the mRNA and protein level. Previous studies have shown that damage of neurons physiologically causes Neuropilin1 and Semaphorin3A increase in the central nervous system and decrease in the peripheral nervous system. Our results indicate that this also occurs in ALS. Pharmacological modulation of expression and function of axon repellents could be a promising future therapeutic option in ALS.

Fibroblast growth factor 2 (FGF-2), ubiquitously expressed in humans and mice, is functionally involved in cell growth, migration and maturation in vitro and in vivo. Based on the same mRNA, an 18-kilo Dalton (kDa) FGF-2 isoform named FGF-2 low molecular weight (FGF-2LMW) isoform is translated in humans and rodents. Additionally, two larger isoforms weighing 21 and 22 kDa also exist, summarized as the FGF-2 high molecular weight (FGF-2HMW) isoform. Meanwhile, the human FGF-2HMW comprises a 22, 23, 24 and 34 kDa protein. Independent studies verified a specific intracellular localization, mode of action and tissue-specific spatiotemporal expression of the FGF-2 isoforms, increasing the complexity of their physiological and pathophysiological roles. In order to analyze their spectrum of effects, FGF-2LMW knock out (ko) and FGF-2HMWko mice have been generated, as well as mice specifically overexpressing either FGF-2LMW or FGF-2HMW. So far, the development and functionality of the cardiovascular system, bone formation and regeneration as well as their impact on the central nervous system including disease models of neurodegeneration, have been examined. This review provides a summary of the studies characterizing the in vivo effects modulated by the FGF-2 isoforms and, thus, offers a comprehensive overview of its actions in the aforementioned organ systems.

We have previously shown that knockout of fibroblast growth factor-2 (FGF-2) and potential compensatory effects of other growth factors result in amelioration of disease symptoms in a transgenic mouse model of amyotrophic lateral sclerosis (ALS). ALS is a rapidly progressive neurological disorder leading to degeneration of cortical, brain stem, and spinal motor neurons followed by subsequent denervation and muscle wasting. Mutations in the superoxide dismutase 1 (SOD1) gene are responsible for approximately 20% of familial ALS cases and SOD1 mutant mice still are among the models best mimicking clinical and neuropathological characteristics of ALS. The aim of the present study was a thorough characterization of FGF-2 and other growth factors and signaling effectors in vivo in the SOD1G93A mouse model. We observed tissue-specific opposing gene regulation of FGF-2 and overall dysregulation of other growth factors, which in the gastrocnemius muscle was associated with reduced downstream extracellular-signal-regulated kinases (ERK) and protein kinase B (AKT) activation. To further investigate whether the effects of FGF-2 on motor neuron death are mediated by glial cells, astrocytes lacking FGF-2 were cocultured together with mutant SOD1 G93A motor neurons. FGF-2 had an impact on motor neuron maturation indicating that astrocytic FGF-2 affects motor neurons at a developmental stage. Moreover, neuronal gene expression patterns showed FGF-2- and SOD1 G93A -dependent changes in ciliary neurotrophic factor, glial-cell-line-derived neurotrophic factor, and ERK2, implying a potential involvement in ALS pathogenesis before the onset of clinical symptoms.

Summary: Precise assembly of the sarcomere, a force-generating unit in striated muscles, is critical for muscle contraction. Defective sarcomere organization is linked to myopathies and cachexia. The molecular mechanisms concerning sarcomere assembly are poorly understood. Here, we report that the SUMO-specific isopeptidase SENP3 determines sarcomere assembly by specifically regulating the sarcomeric contractile myosin heavy-chain gene MyHC-II. The contractile ability of mature muscle cells is severely compromised in SENP3-depleted cells. Mechanistically, SENP3 is associated with the SETD7 histone methyltransferase and deSUMOylates SETD7. By recruiting SETD7 to MyHC-II, SENP3 promotes association of SETD7 with transcriptionally active RNA polymerase II and precludes the opposing methyltransferase Suv39h1. Strikingly, SENP3 is degraded in cachexia, characterized by dramatic loss of sarcomeric protein, particularly MyHC-II. SENP3 regulation of SETD7 is impaired in cachexia, leading to perturbed MyHC-II expression and disorganized sarcomeres. Our findings reveal an unanticipated role of SENP3 in sarcomere assembly and cachexia. : Nayak et al. define the SENP3-governed transcriptional program, which is crucial for correct sarcomere assembly and contractile function of striated muscle cells. The SENP3-mediated transcriptional mechanism is disrupted in cachexia-induced muscle atrophy, leading to sarcomere disorganization and loss of muscle function. Keywords: sarcomere organization, cachexia, SENP3, SUMOylation, SETD7, epigenetics

Despite decades of research on amyotrophic lateral sclerosis (ALS), there is only one approved drug, which minimally extends patient survival. Here, we investigated pathophysiological mechanisms underlying ALS using motor neurons (MNs) differentiated from induced pluripotent stem cells (iPSCs) derived from ALS patients carrying mutations in FUS or SOD1. Patient-derived MNs were less active and excitable compared to healthy controls, due to reduced Na+/K+ ratios in both ALS groups accompanied by elevated potassium channel (FUS) and attenuated sodium channel expression levels (FUS, SOD1). ALS iPSC-derived MNs showed elevated endoplasmic reticulum stress (ER) levels and increased caspase activation. Treatment with the FDA approved drug 4-Aminopyridine (4AP) restored ion-channel imbalances, increased neuronal activity levels and decreased ER stress and caspase activation. This study provides novel pathophysiological data, including a mechanistic explanation for the observed hypoexcitability in patient-derived MNs and a new therapeutic strategy to provide neuroprotection in MNs affected by ALS.