Volume 397, Issue 3

Fifteen years ago we discovered activity-dependent neuroprotective protein (ADNP), and showed that it is essential for brain formation/function. Our protein interaction studies identified ADNP as a member of the chromatin remodeling complex, SWI/SNF also associated with alternative splicing of tau and prediction of tauopathy. Recently, we have identified cytoplasmic ADNP interactions with the autophagy regulating microtubule-associated protein 1 light chain 3 (LC3) and with microtubule end-binding (EB) proteins. The ADNP-EB-binding SIP domain is shared with the ADNP snippet drug candidate, NAPVSIPQ termed NAP (davunetide). Thus, we identified a precise target for ADNP/NAP (davunetide) neuroprotection toward improved drug development.

Oligodendrocytes are dependent on an intact, dynamic microtubule (MT) network, which participates in the elaboration and stabilization of myelin forming extensions, and is essential for cellular sorting processes. The microtubule-associated protein tau is constituent of oligodendrocytes. During culture maturation it is developmentally regulated and important for MT stability, MT formation and intracellular trafficking. Downregulation of tau impairs process outgrowth and the transport of myelin basic protein (MBP) mRNA to the cell periphery. Cells fail to differentiate into MBP-expressing, sheet-forming oligodendrocytes. Tau-positive inclusions originating in oligodendrocytes and white matter pathology are prominent in frontotemporal dementias, such as Pick’s disease, progressive supranuclear palsy and corticobasal degeneration. An impairment or overload of the proteolytic degradation systems, i.e. the ubiquitin proteasomal system and the lysosomal degradation pathway, has been connected to the formation of protein aggregates. Large protein aggregates are excluded from the proteasome and degraded by autophagy, which is a highly selective process and requires receptor proteins for ubiquitinated proteins, including histone deacetylase 6 (HDAC6). HDAC6 is present in oligodendrocytes, and α-tubulin and tau are substrates of HDAC6. In this review our current knowledge of the role of tau and protein aggregate formation in oligodendrocyte cell culture systems is summarized.

In 2014, a slew of structures of glutamate receptors were published, based on crystallography and electron microscopy. Here we review these insights, integrate them with existing knowledge about receptor function and try to understand how the structures relate to the key property of the AMPA receptor – its speed.

Homer1a is upregulated by several different antidepressant measures, including non-pharmacological treatments, like sleep deprivation (SD) and electroconvulsive therapy (ECT) and antidepressant drugs, such as imipramine, fluoxetine and ketamine. Homer1a induction might thus be a crucial joint mechanism for antidepressant therapy in general. However, the upstream signaling pathways that regulate or induce Homer1a expression are still not well understood. The main focus of the present review is to offer an overview of the current knowledge about the potential role of Homer1a in depression and the signaling pathways responsible for Homer1a regulation. It is suggested here that a detailed characterization of the signaling mechanisms leading to Homer1a expression might provide novel therapeutic targets for antidepressant drug development.

In postmitotic neurons, the activation of RAS family small GTPases regulates survival, growth and differentiation. Dysregulation of RAS or its major effector pathway, the cascade of RAF-, mitogen-activated and extracellular-signal regulated kinase kinases (MEK), and extracellular-signal regulated kinases (ERK) causes the RASopathies, a group of neurodevelopmental disorders whose pathogenic mechanisms are the subject of intense research. I here summarize the functions of RAS-RAF-MEK-ERK signaling in neurons in vivo , and discuss perspectives for harnessing this pathway to enable novel treatments for nervous system injury, the RASopathies, and possibly other neurological conditions.

Ageing is a complex deteriorating process that coincides with changes in metabolism, replicative senescence, increased resistance to apoptosis, as well as progressive mitochondria dysfunction that lead to an increase production and accumulation of reactive oxygen species (ROS). Although controversy on the paradigm of the oxidative damage theory of ageing exists, persuasive studies in Caenorhabditis elegans and yeast have demonstrated that manipulation of ROS can modify the process of ageing and influences the damage of proteins, lipids and DNA. In neurons, ageing impacts on the intrinsic neuronal excitability, it decreases the size of neuronal soma and induces the loss of dendrites and dendritic spines. The actin cytoskeleton is an abundant and broadly expressed system that plays critical functions in many cellular processes ranging from cell motility to controlling cell shape and polarity. It is thus hardly surprising that the expression and the function of actin in neurons is crucial for the morphological changes that occur in the brain throughout life. We propose that alterations in actin filament dynamics in dendritic spines may be one of the key events contributing to the initial phases of ageing in the brain.

Chitinase-like proteins (CLPs) are lectins combining properties of cytokines and growth factors. Human CLPs include YKL-40, YKL-39 and SI-CLP that are secreted by cancer cells, macrophages, neutrophils, synoviocytes, chondrocytes and other cells. The best investigated CLP in cancer is YKL-40. Serum and plasma levels of YKL-40 correlate with poor prognosis in breast, lung, prostate, liver, bladder, colon and other types of cancers. In combination with other circulating factors YKL-40 can be used as a predictive biomarker of cancer outcome. In experimental models YKL-40 supports tumor initiation through binding to RAGE, and is able to induce cancer cell proliferation via ERK1/2-MAPK pathway. YKL-40 supports tumor angiogenesis by interaction with syndecan-1 on endothelial cells and metastatic spread by stimulating production of pro-inflammatory and pro-invasive factors MMP9, CCL2 and CXCL2. CLPs induce production of pro- and anti-inflammatory cytokines and chemokines, and are potential modulators of inflammatory tumor microenvironment. Targeting YKL-40 using neutralizing antibodies exerts anti-cancer effect in preclinical animal models. Multifunctional role of CLPs in regulation of inflammation and intratumoral processes makes them attractive candidates for tumor therapy and immunomodulation. In this review we comprehensively analyze recent data about expression pattern, and involvement of human CLPs in cancer.

Key regulatory genes in pluripotent stem cells are of interest not only as reprogramming factors but also as regulators driving tumorigenesis. Nanog is a transcription factor involved in the maintenance of embryonic stem cells and is one of the reprogramming factors along with Oct4 , Sox2 , and Lin28 . Nanog expression has been detected in different types of tumors, and its expression is a poor prognosis for cancer patients. However, there is no clear evidence that Nanog is functionally involved in tumorigenesis. In this study, we induced overexpression of Nanog in mouse embryonic fibroblast cells and subsequently assessed their morphological changes, proliferation rate, and tumor formation ability. We found that Nanog overexpression induced immortalization of mouse embryonic fibroblast cells (MEFs) and increased their proliferation rate in vitro . We also found that formation of tumors after subcutaneous injection of retroviral- Nanog infected MEFs (N-MEFs) into athymic mouse. Cancer-related genes such as Bmi1 were expressed at high levels in N-MEFs. Hence, our results demonstrate that Nanog is able to transform normal somatic cells into tumor cells.

Sulfatase 2 (SULF2) is an extracellular enzyme that catalyzes the removal of 6-O-sulfate groups from the heparan sulfate (HS). As elevated SULF2 activity has been correlated with hepatocellular carcinoma (HCC), this study was conducted to evaluate the chemoprotective and the hepatoprotective roles of adiponectin, as a SULF2 inhibitor, against hepatocellular carcinoma both in vivo and in vitro . HCC was induced in rats using thioacetamide (200 mg/kg). Treated rats received adiponectin (5 μg/kg) once a week. Moreover, human hepatocellular carcinoma (HepG2) cell line was used as an in-vitro model. In both in-vivo and in-vitro models, adiponectin completely blocked HCC-induced SULF2 elevation. The antitumor activity of adiponectin was confirmed by 80% increased the survival rate, 73% reduction in the average number of nodules per nodule-bearing liver and 46% reduction in serum AFP. In addition, adiponectin ameliorated HCC-induced expression of tumor invasion markers, MMP9, syndecan-1 and FGF-2. Moreover, adiponectin attenuated HCC-induced elevation of nfκb and TNF-α levels. Moreover, treatment of HepG2 cell line with adiponectin showed dose-dependent reduction of HepG2 cell viability and elevation of cellular cytotoxicity. Besides, Adiponectin yielded the same results in HepG2 cells in a dose-dependent manner. Adiponectin achieved both hepatoprotective and chemoprotective effects against HCC through blocking of SULF2.

The pathogenic basis of abnormal placentation and dysfunction in preeclampsia (PE) is highly complex and incompletely understood. Secretory sphyngomyelinase activity (S-ASM) was analyzed in plasma samples from 158 pregnant women developing PE and 112 healthy pregnant controls. Serum PlGF, sFlt-1, s-Endoglin and sVCAM were measured. Results showed S-ASM activity to be higher in women who later developed PE than in those with uncomplicated pregnancies (40.6% and 28.8% higher in the late- and early-onset groups, respectively). Plasma S-ASM activity correlated significantly with circulating markers of endothelial damage in the late-PE group (endoglin and sVCAM-1), with plasma cholesterol and total lipid levels. However, these significant associations were not observed in the early-PE or control groups. This work provides the first evidence of significantly elevated circulating S-ASM activity in the first trimester of pregnancy in women who go on to develop PE; thus, it may be deduced that the circulating form of ASM is biologically active in PE and could contribute to promoting endothelial dysfunction and cardiovascular programming. Plasma S-ASM measurement may have clinical relevance as a further potential biomarker contributing to the earliest identification of women at risk of developing preeclampsia.