Neuron-derived Neurotrophic Factor Research Articles

Quantitative proteomics provides new insights into the mechanism underlying textural property improvement in frankfurters by ultrasound treatment combined with κ-carrageenan

This study aimed to reveal the potential mechanism by which ultrasound (US) treatment combined with κ-carrageenan (KC) enhances the textural properties of frankfurters via label-free quantitative proteomics techniques. The results showed that compared with the individual application of US or KC, US combined with KC (US+KC) significantly enhanced the textural properties and decreased the cooking loss of frankfurters (P < 0.05) as well as led to a denser and more compact protein network. Moreover, quantitative proteomics analysis indicated that the US, KC, and US+KC groups had 241, 178, and 211 differentially expressed proteins compared with control group, respectively. Meanwhile, bioinformatic analyses based on Gene Ontology enrichment, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment, and protein–protein interactions demonstrated that the differentially expressed proteins were primarily structural proteins and metabolic enzymes. Furthermore, correlation analyses between differentially expressed proteins and textural indicators revealed that 26 differentially expressed proteins were significantly correlated with changes in the textural properties of frankfurters. In particular, myosin heavy chain 7, cytochrome oxidase subunit 6C, and neuron-derived neurotrophic factor may be considered primary markers for determining the final textural properties of frankfurters. Therefore, the present work revealed a crucial mechanism by which different treatments (US, KC, and US+KC) elicit changes in the textural properties of frankfurters from a proteomic perspective.

Overexpression of NDNF Improves the Cytoprotective Effects of Aged Human Bone Marrow Mesenchymal Stem Cells by Modulating Oxidative Stress and Apoptosis.

The therapeutic potential of autologous stem cell transplantation for heart repair diminishes in the elderly due to stem cell aging. Rejuvenating aged stem cells to enhance their protective effects on injured cardiomyocytes is crucial for aging patients with heart failure. In this study, we aimed to investigate whether neuron-derived neurotrophic factor (NDNF) over-expression improves the protective effect of aged stem cells for injured cardiomyocytes and explore the underlying mechanism. Human bone marrow was collected from both young and old patients, and bone marrow mesenchymal stem cells (BMSCs) were cultured. Lentivirus expression vectors carrying NDNF genes were used to transfect aged BMSCs. Fatal hypoxia-induced injury in H9C2 cells served as an in vitro ischemia model. The conditioned medium from different BMSC groups was applied to assess the beneficial effects on hypoxia-induced damage in myocardial H9C2 cells. Results revealed that the conditioned medium of NDNF over-expressed old BMSCs increased H9C2 cell viability and reduced oxidative stress and apoptosis levels under fatal hypoxia. NDNF over-expressed old BMSCs exhibited an antiapoptotic role by upregulating the antiapoptotic gene Bcl-2 and downregulating the proapoptotic genes Bax. Additionally, the protective effects were mediated through the elevation of phosphorylated AKT. Our data support the promise of NDNF as a potential target to enhance the protective effects of autologous aged BMSCs on ischemic cardiomyocytes and then improve the curative effects of stem cell for ischemic heart injury in aged patients.

Neuron-derived neurotrophic factor promotes the differentiation of intramuscular and subcutaneous adipocytes in goat

Adipocyte play an important role in human health and meat quality by influencing the tenderness, flavor, and juiciness of mutton It has been shown that neuron-derived neurotrophic factor (NENF) is closely related to energy metabolism and adipocyte differentiation in bovine. However, the role of NENF in the goats remains unclear. The aim of this study was to detect the expression of NENF in goat subcutaneous and intramuscular adipocytes, temporal expression profiles of the NENF, and overexpressed NENF on the differentiation of different adipocytes. In this study, PCR amplification successfully cloned the goat NENF gene with a fragment length of 521 bp. In addition, the time point of highest expression of NENF differed between these two adipocytes differentiation processes. Overexpression of NENF in intramuscular and subcutaneous adipocytes promoted the expression levels of differentiation markers CEBPβ and SREBP, which in turn promoted the differentiation of intramuscular and subcutaneous adipocytes. This study will provide basic data for further study of the role of goats in goat adipocyte differentiation and for the final elucidation of its molecular mechanisms in regulating goat adipocyte deposition.

Layer 1 NDNF interneurons are specialized top-down master regulators of cortical circuits

Diverse types of inhibitory interneurons (INs) impart computational power and flexibility to neocortical circuits. Whereas markers for different IN types in cortical layers 2-6 (L2-L6) have been instrumental for generating a wealth of functional insights, only the recent identification of a selective marker (neuron-derived neurotrophic factor [NDNF]) has opened comparable opportunities for INs in L1 (L1INs). However, at present we know very little about the connectivity of NDNF L1INs with other IN types, their input-output conversion, and the existence of potential NDNF L1IN subtypes. Here, we report pervasive inhibition of L2/3 INs (including parvalbumin INs and vasoactive intestinal peptide INs) by NDNF L1INs. Intersectional genetics revealed similar physiology and connectivity in the NDNF L1IN subpopulation co-expressing neuropeptide Y. Finally, NDNF L1INs prominently and selectively engage in persistent firing, a physiological hallmark disconnecting their output from the current input. Collectively, our work therefore identifies NDNF L1INs as specialized master regulators of superficial neocortex according to their pervasive top-down afferents.

Ndnf Interneuron Excitability Is Spared in a Mouse Model of Dravet Syndrome.

Dravet syndrome (DS) is a neurodevelopmental disorder characterized by epilepsy, developmental delay/intellectual disability, and features of autism spectrum disorder, caused by heterozygous loss-of-function variants in SCN1A encoding the voltage-gated sodium channel α subunit Nav1.1. The dominant model of DS pathogenesis is the "interneuron hypothesis," whereby GABAergic interneurons (INs) express and preferentially rely on Nav1.1-containing sodium channels for action potential (AP) generation. This has been shown for three of the major subclasses of cerebral cortex GABAergic INs: those expressing parvalbumin (PV), somatostatin, and vasoactive intestinal peptide. Here, we define the function of a fourth major subclass of INs expressing neuron-derived neurotrophic factor (Ndnf) in male and female DS (Scn1a+/-) mice. Patch-clamp electrophysiological recordings of Ndnf-INs in brain slices from Scn1a+/â mice and WT controls reveal normal intrinsic membrane properties, properties of AP generation and repetitive firing, and synaptic transmission across development. Immunohistochemistry shows that Nav1.1 is strongly expressed at the axon initial segment (AIS) of PV-expressing INs but is absent at the Ndnf-IN AIS. In vivo two-photon calcium imaging demonstrates that Ndnf-INs in Scn1a+/â mice are recruited similarly to WT controls during arousal. These results suggest that Ndnf-INs are the only major IN subclass that does not prominently rely on Nav1.1 for AP generation and thus retain their excitability in DS. The discovery of a major IN subclass with preserved function in the Scn1a+/â mouse model adds further complexity to the "interneuron hypothesis" and highlights the importance of considering cell-type heterogeneity when investigating mechanisms underlying neurodevelopmental disorders.

A combinatory genetic strategy for targeting neurogliaform neurons in the mouse basolateral amygdala.

The mouse basolateral amygdala (BLA) contains various GABAergic interneuron subpopulations, which have distinctive roles in the neuronal microcircuit controlling numerous behavioral functions. In mice, roughly 15% of the BLA GABAergic interneurons express neuropeptide Y (NPY), a reasonably characteristic marker for neurogliaform cells (NGFCs) in cortical-like brain structures. However, genetically labeled putative NPY-expressing interneurons in the BLA yield a mixture of interneuron subtypes besides NGFCs. Thus, selective molecular markers are lacking for genetically accessing NGFCs in the BLA. Here, we validated the NGFC-specific labeling with a molecular marker, neuron-derived neurotrophic factor (NDNF), in the mouse BLA, as such specificity has been demonstrated in the neocortex and hippocampus. We characterized genetically defined NDNF-expressing (NDNF+) GABAergic interneurons in the mouse BLA by combining the Ndnf-IRES2-dgCre-D transgenic mouse line with viral labeling, immunohistochemical staining, and in vitro electrophysiology. We found that BLA NDNF+ GABAergic cells mainly expressed NGFC neurochemical markers NPY and reelin (Reln) and exhibited small round soma and dense axonal arborization. Whole-cell patch clamp recordings indicated that most NDNF+ interneurons showed late spiking and moderate firing adaptation. Moreover, ∼81% of BLA NDNF+ cells generated retroaxonal action potential after current injections or optogenetic stimulations, frequently developing into persistent barrage firing. Optogenetic activation of the BLA NDNF+ cell population yielded both GABAA- and GABAB receptor-mediated currents onto BLA pyramidal neurons (PNs). We demonstrate a combinatory strategy combining the NDNF-cre mouse line with viral transfection to specifically target adult mouse BLA NGFCs and further explore their functional and behavioral roles.

Target Antigens of Membranous Nephropathy With Syphilis Infection

IntroductionMembranous nephropathy is the most common cause of proteinuria in syphilis, and neuron-derived neurotrophic factor (NDNF) is recently demonstrated to be the target antigen in syphilis-associated membranous nephropathy. However, the prevalence and clinicopathological characteristics of both NDNF-positive and NDNF-negative membranous nephropathy in Chinese individuals with syphilis infection still remain unknown. MethodsA retrospective study was conducted in 17 membranous nephropathy patients with history of syphilis infection. The intensity and distribution of NDNF staining, as well as phospholipase A2 receptor (PLA2R) and neural epidermal growth factor-like 1 protein (NELL-1) staining in renal biopsies were assessed. ResultsAmong the 11 membranous nephropathy patients with active syphilis infection, positive NDNF staining was shown in 5 patients (46%). The remaining six patients demonstrated negative NDNF staining. Of which, 5 patients were PLA2R positive and the other one was PLA2R and NELL-1 negative. Antibiotics were also effective in three NDNF-negative patients, suggesting the possibility of syphilis-associated membranous nephropathy. Thus, the histological positivity rate of NDNF was 63% (5/8 patients) in syphilis-associated membranous nephropathy. In addition, positive NDNF antibody was first confirmed in the serum of one NDNF associated membranous nephropathy patient. NDNF staining was negative in all 6 membranous nephropathy patients with previous syphilis infection. ConclusionsNearly half of the patients with active syphilis infection and membranous nephropathy were NDNF-positive in our study. Positive NDNF staining favors syphilis-associated membranous nephropathy. Circulating anti-NDNF antibody can be detected in the patient’s serum sample. In addition, PLA2R or other unknown antigenic protein may also be the target antigens for syphilis-associated membranous nephropathy in Chinese population.

New Insights on the Progesterone (P4) and PGRMC1/NENF Complex Interactions in Colorectal Cancer Progression.

The literature data regarding the risk of colorectal cancer (CRC) in the context of hormone therapy (HT), including both estrogen-progestogen combinations and estrogen alone, are inconclusive. The precise relationship underlying the action of progesterone (P4) and progesterone receptors in CRC has yet to be determined. We characterized the expression profiles of both nuclear and membrane progesterone receptors and their potential cofactors in CRC tissues. Additionally, we analyzed the P4 and NENF treatment effects on the cell proliferation and invasion of DLD-1 and HT-29 colorectal cancer cells. We observed a weak expression of the nuclear P4 receptor (PGR), but an abundant expression of the P4 receptor membrane component 1 (PGRMC1) and neuron-derived neurotrophic factor (NENF) in the CRC tissues. P4 treatment stimulated the proliferation of the DLD-1 and HT-29 CRC cells. The co-treatment of P4 and NENF significantly increased the invasiveness of the DLD-1 and HT-29 cells. A functional analysis revealed that these effects were dependent on PGRMC1. AN immunocytochemical analysis demonstrated a cytoplasmic co-localization of PGRMC1 and NENF in the CRC cells. Moreover, the concentration of serum NENF was significantly higher in CRC patients, and P4 treatment significantly increased the release of NENF in the DLD-1 cells. P4 or NENF treatment also significantly increased the IL-8 release in the DLD-1 cells. Our data may provide novel insights into the action of P4 and PGRMC1/NENF in CRC progression, where NENF may act as a potential PGRMC1 co-activator in non-classical P4 signaling. Furthermore, NENF, as a secreted protein, potentially could serve as a promising circulating biomarker candidate for distinguishing between colorectal cancer patients and healthy individuals, although large-scale extensive studies are needed to establish this.

Intrathecal delivery of AAV-NDNF ameliorates disease progression of ALS mice

Amyotrophic lateral sclerosis (ALS) is a uniformly lethal neurodegenerative disease characterized by progressive deterioration of motor neurons and neuromuscular denervation. Adeno-associated virus (AAV)-mediated delivery of trophic factors is being considered as a potential disease-modifying therapeutic avenue. Here we show a marked effect of AAV-mediated over-expression of neuron-derived neurotrophic factor (NDNF) on SOD1G93A ALS model mice. First, we adopt AAV-PHP.eB capsid to enable widespread expression of target proteins in the brain and spinal cord when delivered intrathecally. Then we tested the effects of AAV-NDNF on SOD1G93A mice at different stages of disease. Interestingly, AAV-NDNF markedly improved motor performance and alleviated weight loss when delivered at early post-symptomatic stage. Injection in the middle post-symptomatic stages still improved the locomotion ability, although it did not alleviate the loss of body weight. Injection in the late stage also extended the life span of SOD1G93A mice. Furthermore, NDNF expression promoted the survival of spinal motoneurons, reduced abnormal protein aggregation, and preserved the innervated neuromuscular functions. We further analyzed the signaling pathways of NDNF expression and found that it activates cell survival and growth-associated mammalian target of rapamycin signaling pathway and downregulates apoptosis-related pathways. Thus, intrathecally AAV-NDNF delivery has provided a potential strategy for the treatment of ALS.

Membranous Nephropathy in Syphilis is Associated with Neuron-Derived Neurotrophic Factor.

Syphilis is a common worldwide sexually transmitted infection. Proteinuria may occur in patients with syphilis. Membranous nephropathy (MN) is the most common cause of proteinuria in syphilis. The target antigen of MN in syphilis is unknown. This study shows that MN in syphilis is associated with a novel target antigen called neuron-derived neurotrophic factor (NDNF). NDNF-associated MN has distinctive clinical and pathologic manifestations and NDNF appears to be the target antigen in syphilis-associated MN. Syphilis is a common sexually transmitted infection. Membranous nephropathy (MN) is a common cause of proteinuria in syphilis. The target antigen is not known in most cases of syphilis-associated MN. We performed laser microdissection of glomeruli and mass spectrometry (MS/MS) in 250 cases (discovery cohort) of phospholipase A2 receptor-negative MN to identify novel target antigens. This was followed by immunohistochemistry/confocal microscopy to localize the target antigen along the glomerular basement membrane (GBM). Western blot analyses using IgG eluted from frozen biopsy tissue were performed to detect binding to target antigen. MS/MS studies of the discovery cohort revealed high total spectral counts of a novel protein, neuron-derived neurotrophic factor (NDNF), in three patients: one each with syphilis and hepatitis B, HIV (syphilis status not known), and lung tumor. Next, MS/MS studies of five cases of syphilis-MN (validation cohort) confirmed high total spectral counts of NDNF (average 45±20.4) in all (100%) cases. MS/MS of 14 cases of hepatitis B were negative for NDNF. All eight cases of NDNF-associated MN were negative for known MN antigens. Electron microscopy showed stage I MN in all cases, with superficial and hump-like deposits without GBM reaction. IgG1 was the dominant IgG subtype on MS/MS and immunofluorescence microscopy. Immunohistochemistry/confocal microscopy showed granular staining and colocalization of NDNF and IgG along GBM. Western blot analyses using eluate IgG of NDNF-MN showed binding to both nonreduced and reduced NDNF, while IgG eluate from phospholipase A2 receptor-MN showed no binding. NDNF is a novel antigenic target in syphilis-associated MN.

Video-based pooled screening yields improved far-red genetically encoded voltage indicators.

Video-based screening of pooled libraries is a powerful approach for directed evolution of biosensors because it enables selection along multiple dimensions simultaneously from large libraries. Here we develop a screening platform, Photopick, which achieves precise phenotype-activated photoselection over a large field of view (2.3 × 2.3 mm, containing >103 cells, per shot). We used the Photopick platform to evolve archaerhodopsin-derived genetically encoded voltage indicators (GEVIs) with improved signal-to-noise ratio (QuasAr6a) and kinetics (QuasAr6b). These GEVIs gave improved signals in cultured neurons and in live mouse brains. By combining targeted in vivo optogenetic stimulation with high-precision voltage imaging, we characterized inhibitory synaptic coupling between individual cortical NDNF (neuron-derived neurotrophic factor) interneurons, and excitatory electrical synapses between individual hippocampal parvalbumin neurons. The QuasAr6 GEVIs are powerful tools for all-optical electrophysiology and the Photopick approach could be adapted to evolve a broad range of biosensors.

Hsa_Circ_0134426 Attenuates the Malignant Biological Behaviors of Multiple Myeloma by Suppressing miR-146b-3p to Upregulate NDNF.

We focused on hsa_circ_0134426 (circ_0134426) to determine its functional effects and targets in multiple myeloma (MM) development. The relative expression of circ_0134426, miR-146b-3p, and neuron-derived neurotrophic factor (NDNF) in the MM samples was confirmed by quantitative real-time PCR (qPCR) or western blotting. The protein levels of epithelial-to-mesenchymal transition (EMT)-linked markers were identified using western blotting. Xenograft models in nude mice were used for in vivo functional analysis of circ_0134426. The binding of miR-146b-3p to circ_0134426 or NDNF was confirmed by dual-luciferase and RIP assays. Poor levels of circ_0134426 and NDNF and high levels of miR-146b-3p were observed in MM bone marrow samples and cell lines. Circ_0134426 overexpression blocked MM cell growth, colony formation, and migration and impeded tumor development in xenograft models. circRNA_0134426 decoys miR-146b-3p to repress its expression. Overexpression of miR-146b-3p restored MM cell activities that were blocked by circ_0134426 overexpression. NDNF is a functional molecule targeted by miR-146b-3p, and miR-146b-3p sequesters NDNF expression. The inhibitory effects of NDNF upregulation on MM cell growth, colony formation, and migration were partially abolished by miR-146b-3p overexpression. Circ_0134426 regulates the miR-146b-3p/NDNF network to restrain the development of MM, to some extent, suggesting that the development of MM therapeutic strategies might focus on circ_0134426 regulatory networks.

Testicular Hypoplasia with Normal Fertility in Neudesin-Knockout Mice.

Neudesin is a secretory protein involved in the brain development during embryonic period and diet-induced development of adipose tissue. Although neudesin is also expressed in the testis, its physiological functions in the testis have not been documented. Therefore, we examined neudesin-encoding neuron-derived neurotrophic factor (Nenf) gene-knockout (Neudesin-KO) mice to clarify the functions of neudesin in the testis. The testicular size of the Neudesin-KO mice was significantly smaller than that of wild-type (WT) mice. However, histological analyses did not reveal any abnormalities in the testis, caput epididymis, and cauda epididymis. Sperm number in the cauda epididymis was comparable between WT and KO mice. Neudesin-KO male mice produced vaginal plugs on paired WT female mice, with a frequency similar to that in WT male mice. A similar number of embryos were developed in the females copulated with WT and Neudesin-KO males. Molecular analysis indicated that the ion transporters Slc19a1 and Kcnk3 were more expressed in the testis of Neudesin-KO mice than in the testis of WT mice, suggesting that the transport of ions and some nutrients in the testis has some abnormalities. Testicular size decreased on postnatal day 6, but not on the day of birth, indicating that neudesin is involved in the postnatal, but not embryonic, development of testis. These results indicate a novel role of neudesin in the development of testis.

Neuron-Derived Neurotrophic Factor (NDNF) Is a Novel Protein Associated With Membranous Nephropathy (MN)

Neuron-Derived Neurotrophic Factor (NDNF) Is a Novel Protein Associated With Membranous Nephropathy (MN)

Long-term potentiation in neurogliaform interneurons modulates excitation-inhibition balance in the temporoammonic pathway.

Apical dendrites of pyramidal neurons integrate information from higher‐order cortex and thalamus, and gate signalling and plasticity at proximal synapses. In the hippocampus, neurogliaform cells and other interneurons located within stratum lacunosum‐moleculare (SLM) mediate powerful inhibition of CA1 pyramidal neuron distal dendrites. Is the recruitment of such inhibition itself subject to use‐dependent plasticity, and if so, what induction rules apply? Here we show that interneurons in mouse SLM exhibit Hebbian NMDA receptor‐dependent long‐term potentiation (LTP). Such plasticity can be induced by selective optogenetic stimulation of afferents in the temporoammonic pathway from the entorhinal cortex (EC), but not by equivalent stimulation of afferents from the thalamic nucleus reuniens. We further show that theta‐burst patterns of afferent firing induces LTP in neurogliaform interneurons identified using neuron‐derived neurotrophic factor (Ndnf)‐Cre mice. Theta‐burst activity of EC afferents led to an increase in disynaptic feed‐forward inhibition, but not monosynaptic excitation, of CA1 pyramidal neurons. Activity‐dependent synaptic plasticity in SLM interneurons thus alters the excitation–inhibition balance at EC inputs to the apical dendrites of pyramidal neurons, implying a dynamic role for these interneurons in gating CA1 dendritic computations. Key points Electrogenic phenomena in distal dendrites of principal neurons in the hippocampus have a major role in gating synaptic plasticity at afferent synapses on proximal dendrites. Apical dendrites also receive powerful feed‐forward inhibition, mediated in large part by neurogliaform neurons.Here we show that theta‐burst activity in afferents from the entorhinal cortex (EC) induces ‘Hebbian’ long‐term potentiation (LTP) at excitatory synapses recruiting these GABAergic cells.LTP in interneurons innervating apical dendrites increases disynaptic inhibition of principal neurons, thus shifting the excitation–inhibition balance in the temporoammonic (TA) pathway in favour of inhibition, with implications for computations and learning rules in proximal dendrites.

The Role of Neudesin as a Novel Biomarker – in Iraqi Patients with Parkinson's Disease and Osteoporosis

Neuron-derived neurotrophic factor [NENF], a human plasma neurotrophic factor, also increases neurotrophic activity in conjunction with Parkinson's disease-related proteins in Neudesin. Although Neudesin (neuron-derived neurotrophic secreted protein) is a member of the membrane-associated progesterone receptor (MAPR) protein subclass, it is not evolutionary related to the other members of the same family. The expression of Neudesin is found in both brain and spinal cord from embryonic stages to adulthood, as w Neudesin levels in Parkinson's patients with osteoporosis disease and Parkinson's patients without osteoporosis disease, as well as the relationship between Neudesin levels, Anthropometric and Clinical Features (Age, Gender, BMI) and Serum Parathyroid Hormones vit D3, Ca and phosphorous, were studied in this study. Eighty individuals participated in this study. Osteoporosis is a risk factor for Parkinson's, and Osteoporosis is a risk factor for Parkinson's disease. In order to conduct this study, we selected patients from the Parkinson's Disease and Osteoporosis Center in Baghdad/ Alrisafa. G1 and G2 were (55-67) years old, (38-75) years old, and (55-66) years old, respectively. In all of the groups examined, the ratio of males to females has risen. Men are more likely than women to be diagnosed with Parkinson's disease, accounting for this disparity. Neudesin concentrations in G1 and G3 were substantially lower than those in G2 (P= ±0.0001), although G1's concentration was somewhat higher than G2's (0.803±0.091 ng./ml). A "cut-off value" for determining sensitivity and specificity to diagnose the condition was also determined in the study, which included examining the link between blood Neudesin levels and the classification of participants into cases and controls.

The NDNF-like factor Nord is a Hedgehog-induced extracellular BMP modulator that regulates Drosophila wing patterning and growth.

Hedgehog (Hh) and Bone Morphogenetic Proteins (BMPs) pattern the developing Drosophila wing by functioning as short- and long-range morphogens, respectively. Here, we show that a previously unknown Hh-dependent mechanism fine-tunes the activity of BMPs. Through genome-wide expression profiling of the Drosophila wing imaginal discs, we identify nord as a novel target gene of the Hh signaling pathway. Nord is related to the vertebrate Neuron-Derived Neurotrophic Factor (NDNF) involved in congenital hypogonadotropic hypogonadism and several types of cancer. Loss- and gain-of-function analyses implicate Nord in the regulation of wing growth and proper crossvein patterning. At the molecular level, we present biochemical evidence that Nord is a secreted BMP-binding protein and localizes to the extracellular matrix. Nord binds to Decapentaplegic (Dpp) or the heterodimer Dpp-Glass-bottom boat (Gbb) to modulate their release and activity. Furthermore, we demonstrate that Nord is a dosage-dependent BMP modulator, where low levels of Nord promote and high levels inhibit BMP signaling. Taken together, we propose that Hh-induced Nord expression fine-tunes both the range and strength of BMP signaling in the developing Drosophila wing.

Neuron-derived neurotrophic factor protects against dexamethasone-induced skeletal muscle atrophy

Skeletal muscle atrophy caused by various conditions including aging, nerve damage, and steroid administration, is a serious health problem worldwide. We recently reported that neuron-derived neurotrophic factor (NDNF) functions as a muscle-derived secreted factor, also known as myokine, which exerts protective actions on endothelial cell and cardiomyocyte function. Here, we investigated whether NDNF regulates skeletal muscle atrophy induced by steroid administration and sciatic denervation.NDNF-knockout (KO) mice and age-matched wild-type (WT) mice were subjected to continuous dexamethasone (DEX) treatment or sciatic denervation. NDNF-KO mice exhibited decreased gastrocnemius muscle weight and reduced cross sectional area of myocyte fiber after DEX treatment or sciatic denervation compared with WT mice. Administration of an adenoviral vector expressing NDNF (Ad-NDNF) or recombinant NDNF protein to gastrocnemius muscle of WT mice increased gastrocnemius muscle weight after DEX treatment. NDNF-KO mice showed increased expression of ubiquitin E3-ligases, including atrogin-1 and MuRF-1, in gastrocnemius muscle after DEX treatment, whereas Ad-NDNF reduced expression of atrogin-1 and MuRF-1 in gastrocnemius muscle of WT mice after DEX treatment. Pretreatment of cultured C2C12 myocytes with NDNF protein reversed reduced myotube diameter and increased expression of atrogin-1 and MuRF-1 after DEX stimulation. Treatment of C2C12 myocytes increased Akt phosphorylation. Pretreatment of C2C12 myotubes with the PI3-kinase/Akt inhibitor reversed NDNF-induced increase in myotube fiber diameter after DEX treatment. In conclusion, our findings indicated that NDNF prevents skeletal muscle atrophy in vivo and in vitro through reduction of ubiquitin E3-ligases expression, suggesting that NDNF could be a novel therapeutic target of muscle atrophy.

Hippocampal and thalamic afferents form distinct synaptic microcircuits in the mouse infralimbic frontal cortex.

The selection of goal-directed behaviors is supported by neural circuits located within the frontal cortex. Frontal cortical afferents arise from multiple brain areas, yet the cell-type-specific targeting of these inputs is unclear. Here, we use monosynaptic retrograde rabies mapping to examine the distribution of afferent neurons targeting distinct classes of local inhibitory interneurons and excitatory projection neurons in mouse infralimbic frontal cortex. Interneurons expressing parvalbumin, somatostatin, or vasoactive intestinal peptide receive a large proportion of inputs from the hippocampus, while interneurons expressing neuron-derived neurotrophic factor receive a large proportion of inputs from thalamic regions. A similar dichotomy is present among the four different excitatory projection neurons. These results show a prominent bias among long-range hippocampal and thalamic afferent systems in their targeting to specific sets of frontal cortical neurons. Moreover, they suggest the presence of two distinct local microcircuits that control how different inputs govern frontal cortical information processing.

NDNF interneurons, Spartans of the cortical column: Small in number, strong in impact

NDNF selectively labels neurogliaform inhibitory interneurons of layer 1. In this issue of Neuron, Cohen-Kashi Malina etal. (2021) show that NDNF activity is highly correlated with arousal level. During high arousal state, NDNF inhibits the dendrites while disinhibiting the soma of nearby pyramidal neurons.