AB1530 Sigma-AldrichAnti-Peripherin Antibody

Reprogramming somatic cells from one cell fate to another can generate specific neurons suitable for disease modeling. To maximize the utility of patient-derived neurons, they must model not only disease-relevant cell classes, but also the diversity of neuronal subtypes found in vivo and the pathophysiological changes that underlie specific clinical diseases. We identified five transcription factors that reprogram mouse and human fibroblasts into noxious stimulus-detecting (nociceptor) neurons. These recapitulated the expression of quintessential nociceptor-specific functional receptors and channels found in adult mouse nociceptor neurons, as well as native subtype diversity. Moreover, the derived nociceptor neurons exhibited TrpV1 sensitization to the inflammatory mediator prostaglandin E2 and the chemotherapeutic drug oxaliplatin, modeling the inherent mechanisms underlying inflammatory pain hypersensitivity and painful chemotherapy-induced neuropathy. Using fibroblasts from patients with familial dysautonomia (hereditary sensory and autonomic neuropathy type III), we found that the technique was able to reveal previously unknown aspects of human disease phenotypes in vitro.

Humans and mice detect pain, itch, temperature, pressure, stretch and limb position via signaling from peripheral sensory neurons. These neurons are divided into three functional classes (nociceptors/pruritoceptors, mechanoreceptors and proprioceptors) that are distinguished by their selective expression of TrkA, TrkB or TrkC receptors, respectively. We found that transiently coexpressing Brn3a with either Ngn1 or Ngn2 selectively reprogrammed human and mouse fibroblasts to acquire key properties of these three classes of sensory neurons. These induced sensory neurons (iSNs) were electrically active, exhibited distinct sensory neuron morphologies and matched the characteristic gene expression patterns of endogenous sensory neurons, including selective expression of Trk receptors. In addition, we found that calcium-imaging assays could identify subsets of iSNs that selectively responded to diverse ligands known to activate itch- and pain-sensing neurons. These results offer a simple and rapid means for producing genetically diverse human sensory neurons suitable for drug screening and mechanistic studies.

Neuroblastoma is a common solid malignant tumor of the sympathetic nervous system, which contributes to 15% of cancer‑related mortality in children. The differentiation status of neuroblastoma is correlated with clinical outcome, and the induction of differentiation thus constitutes a therapeutic approach in this disease. However, the molecular mechanisms that control the differentiation of neuroblastoma remain poorly understood. The present study aimed to define whether GATA3 is involved in the differentiation of neuroblastoma cells. The results demonstrated that GATA3 is a prognostic marker for survival in patients with neuroblastoma, and that high‑level GATA3 expression is associated with increased self‑renewal and proliferation of neuroblastoma cells. Retinoic acid treatment led to GATA3 downregulation together with neuronal differentiation, suppression of cell proliferation and inhibition of tumorigenecity in neuroblastoma cells. These findings suggest that GATA3 is a key regulator of neuroblastoma differentiation, and provide a novel potential therapeutic strategy for the induction of neuroblastoma differentiation.

Individuals with an inherited deficiency in gonadotropin-releasing hormone (GnRH) have impaired sexual reproduction. Previous genetic linkage studies and sequencing of plausible gene candidates have identified mutations associated with inherited GnRH deficiency, but the small number of affected families and limited success in validating candidates have impeded genetic diagnoses for most patients. Using a combination of exome sequencing and computational modeling, we have identified a shared point mutation in semaphorin 3E (SEMA3E) in 2 brothers with Kallmann syndrome (KS), which causes inherited GnRH deficiency. Recombinant wild-type SEMA3E protected maturing GnRH neurons from cell death by triggering a plexin D1-dependent (PLXND1-dependent) activation of PI3K-mediated survival signaling. In contrast, recombinant SEMA3E carrying the KS-associated mutation did not protect GnRH neurons from death. In murine models, lack of either SEMA3E or PLXND1 increased apoptosis of GnRH neurons in the developing brain, reducing innervation of the adult median eminence by GnRH-positive neurites. GnRH neuron deficiency in male mice was accompanied by impaired testes growth, a characteristic feature of KS. Together, these results identify SEMA3E as an essential gene for GnRH neuron development, uncover a neurotrophic function for SEMA3E in the developing brain, and elucidate SEMA3E/PLXND1/PI3K signaling as a mechanism that prevents GnRH neuron deficiency.

Spinal muscular atrophy (SMA) is an autosomal recessive disorder leading to paralysis and early death due to reduced SMN protein. It is unclear why there is such a profound motor neuron loss, but recent evidence from fly and mouse studies indicate that cells comprising the whole sensory-motor circuit may contribute to motor neuron dysfunction and loss. Here, we used induced pluripotent stem cells derived from SMA patients to test whether sensory neurons directly contribute to motor neuron loss. We generated sensory neurons from SMA induced pluripotent stem cells and found no difference in neuron generation or survival, although there was a reduced calcium response to depolarizing stimuli. Using co-culture of SMA induced pluripotent stem cell derived sensory neurons with control induced pluripotent stem cell derived motor neurons, we found no significant reduction in motor neuron number or glutamate transporter boutons on motor neuron cell bodies or neurites. We conclude that SMA sensory neurons do not overtly contribute to motor neuron loss in this human stem cell system.

The gastric ligaments are superficial cord-like structures, located on the lesser curvature of the stomach, that extend from the pylorus to the esophagus. These ligaments have been documented in a wide variety of mammalian species, including humans, but their composition and ontogeny is unexplored. Here, we demonstrate that, during ontogeny, the gastric ligaments are first visible as extensions from a C-shaped domain of Gata3-expressing cells that surround the future pylorus; this domain will later give rise to the pyloric outer longitudinal muscle (OLM). The open ends of the C are located ventrally, and, beginning at embryonic day (E) 13.5, the ligaments grow anteriorly from these points. Whereas most other ligaments of the stomach are neurovascular in nature, the gastric ligaments are composed of smooth muscle cells that mature between E14.5 and E16.5. The gastric ligaments coexpress the transcription factors Gata3, Nkx2-5, and Sox9, and germline loss of Gata3 or conditional deletion of Nkx2-5 abrogates Sox9 expression and impairs gastric ligament smooth muscle development; similar phenotypes were previously seen in the OLM. In accord with this molecular contiguity between the OLM and gastric ligaments, three-dimensional image reconstruction highlights physical contiguity between these smooth muscle structures, suggesting that they may work together as a unit to control flexure of the pyloric region, a function similar to the ligament of Treitz at the duodenojejunal junction. These findings may have implications for our understanding of normal pyloric sphincter function, as well as the common human congenital pathology idiopathic hypertrophic pyloric stenosis.

In mammals, the sensory hair cells and auditory neurons do not spontaneously regenerate and their loss results in permanent hearing impairment. Stem cell therapy is one emerging strategy that is being investigated to overcome the loss of sensory cells after hearing loss. To successfully replace auditory neurons, stem cell-derived neurons must be electrically active, capable of organized outgrowth of processes, and of making functional connections with appropriate tissues. We have developed an in vitro assay to test these parameters using cocultures of developing cochlear explants together with neural progenitors derived from human embryonic stem cells (hESCs). We found that these neural progenitors are electrically active and extend their neurites toward the sensory hair cells in cochlear explants. Importantly, this neurite extension was found to be significantly greater when neural progenitors were predifferentiated toward a neural crest-like lineage. When grown in coculture with hair cells only (denervated cochlear explants), stem cell-derived processes were capable of locating and growing along the hair cell rows in an en passant-like manner. Many presynaptic terminals (synapsin 1-positive) were observed between hair cells and stem cell-derived processes in vitro. These results suggest that differentiated hESC-derived neural progenitors may be useful for developing therapies directed at auditory nerve replacement, including complementing emerging hair cell regeneration therapies.

Chronic pain associated with injury or disease can result from dysfunction of sensory afferents whereby the threshold for activation of pain-sensing neurons (nociceptors) is lowered. Neurotrophic factors control nociceptor development and survival, but also induce sensitization through activation of their cognate receptors, attributable, in part, to the modulation of ion channel function. Thermal pain is mediated by channels of the transient receptor potential (TRP) family, including the cold and menthol receptor TRPM8. Although it has been shown that TRPM8 is involved in cold hypersensitivity, the molecular mechanisms underlying this pain modality are unknown. Using microarray analyses to identify mouse genes enriched in TRPM8 neurons, we found that the glial cell line-derived neurotrophic factor (GDNF) family receptor GFRα3 is expressed in a subpopulation of TRPM8 sensory neurons that have the neurochemical profile of cold nociceptors. Moreover, we found that artemin, the specific GFRα3 ligand that evokes heat hyperalgesia, robustly sensitized cold responses in a TRPM8-dependent manner in mice. In contrast, GFRα1 and GFRα2 are not coexpressed with TRPM8 and their respective ligands GDNF and neurturin did not induce cold pain, whereas they did evoke heat hyperalgesia. Nerve growth factor induced mild cold sensitization, consistent with TrkA expression in TRPM8 neurons. However, bradykinin failed to alter cold sensitivity even though its receptor expresses in a subset of TRPM8 neurons. These results show for the first time that only select neurotrophic factors induce cold sensitization through TRPM8 in vivo, unlike the broad range of proalgesic agents capable of promoting heat hyperalgesia.

The expression of transient receptor potential vanilloid type 1 channel (TRPV1) in the enteric nervous system is still the subject of debate. Although a number of studies have reported that TRPV1 is limited to extrinsic afferent fibers, other studies argue for an intrinsic expression of TRPV1. In the present study, reverse transcriptase PCR was employed to establish the expression of TRPV1 mRNA throughout the gastrointestinal tract. Using two antibodies directed against different epitopes of TRPV1, we were able to show at the protein level that the observed distribution pattern of TRPV1 is dependent on the antibody used in the immunohistochemical staining. A first antibody indeed mainly stained neuronal fibers, whereas a second antibody exclusively stained perikarya of enteric neurons throughout the mouse gastrointestinal tract. We argue that these different distribution patterns are due to the antibodies discriminating between different modulated forms of TRPV1 that influence the recognition of the targeted immunogen and as such distinguish intracellular from plasmalemmal forms of TRPV1. Our study is the first to directly compare these two antibodies within the same species and in identical conditions. Our observations underline that detailed knowledge of the epitope that is recognized by the antibodies employed in immunohistochemical procedures is a prerequisite for correctly interpreting experimental results.

Hearing depends on correct functioning of the cochlear hair cells, and their innervation by spiral ganglion neurons. Most of the insight into the embryological and molecular development of this sensory system has been derived from animal studies. In contrast, little is known about the molecular expression patterns and dynamics of signaling molecules during normal fetal development of the human cochlea. In this study, we investigated the onset of hair cell differentiation and innervation in the human fetal cochlea at various stages of development.At 10 weeks of gestation, we observed a prosensory domain expressing SOX2 and SOX9/SOX10 within the cochlear duct epithelium. In this domain, hair cell differentiation was consistently present from 12 weeks, coinciding with downregulation of SOX9/SOX10, to be followed several weeks later by downregulation of SOX2. Outgrowing neurites from spiral ganglion neurons were found penetrating into the cochlear duct epithelium prior to hair cell differentiation, and directly targeted the hair cells as they developed. Ubiquitous Peripherin expression by spiral ganglion neurons gradually diminished and became restricted to the type II spiral ganglion neurons by 18 weeks. At 20 weeks, when the onset of human hearing is thought to take place, the expression profiles in hair cells and spiral ganglion neurons matched the expression patterns of the adult mammalian cochleae.Our study provides new insights into the fetal development of the human cochlea, contributing to our understanding of deafness and to the development of new therapeutic strategies to restore hearing.