Self-organizing models of human trunk organogenesis recapitulate spinal cord and spine co-morphogenesis

Integrated in vitro models of human organogenesis are needed to elucidate the multi-systemic events underlying development and disease. Here we report the generation of human trunk-like structures that model the co-morphogenesis, patterning and differentiation of the human spine and spinal cord. We identified differentiation conditions for human pluripotent stem cells favoring the formation of an embryo-like extending antero-posterior (AP) axis. Single-cell and spatial transcriptomics show that somitic and spinal cord differentiation trajectories organize along this axis and can self-assemble into a neural tube surrounded by somites upon extracellular matrix addition. Morphogenesis is coupled with AP patterning mechanisms, which results, at later stages of organogenesis, in in vivo-like arrays of neural subtypes along a neural tube surrounded by spine and muscle progenitors contacted by neuronal projections. This integrated system of trunk development indicates that in vivo-like multi-tissue co-morphogenesis and topographic organization of terminal cell types can be achieved in human organoids, opening windows for the development of more complex models of organogenesis.

Propagation of Distinct α-Synuclein Strains Within Human Reconstructed Neuronal Network and Associated Neuronal Dysfunctions

Aggregated alpha-synuclein (α-Syn) in neurons is a hallmark of Parkinson's disease (PD) and other synucleinopathies. Recent advances (1) in the production and purification of synthetic assemblies of α-Syn, (2) in the design and production of microfluidic devices allowing the construction of oriented and compartmentalized neuronal network on a chip, and (3) in the differentiation of human pluripotent stem cells (hPSCs) into specific neuronal subtypes now allow the study of cellular and molecular determinants of the prion-like properties of α-Syn in vitro. Here, we described the methods we used to reconstruct a cortico-cortical human neuronal network in microfluidic devices and how to take advantage of this cellular model to characterize (1) the prion-like properties of different α-Syn strains and (2) the neuronal dysfunctions and the alterations associated with the exposure to α-Syn strains or the nucleation of endogenous α-Syn protein in vitro.

Neurogranin Regulates Adult-Born Olfactory Granule Cell Spine Density and Odor-Reward Associative Memory in Mice

Neurogranin (Ng) is a brain-specific postsynaptic protein, whose role in modulating Ca²⁺/calmodulin signaling in glutamatergic neurons has been linked to enhancement in synaptic plasticity and cognitive functions. Accordingly, Ng knock-out (Ng-ko) mice display hippocampal-dependent learning and memory impairments associated with a deficit in long-term potentiation induction. In the adult olfactory bulb (OB), Ng is expressed by a large population of GABAergic granule cells (GCs) that are continuously generated during adult life, undergo high synaptic remodeling in response to the sensory context, and play a key role in odor processing. However, the possible implication of Ng in OB plasticity and function is yet to be investigated. Here, we show that Ng expression in the OB is associated with the mature state of adult-born GCs, where its active-phosphorylated form is concentrated at post-synaptic sites. Constitutive loss of Ng in Ng-ko mice resulted in defective spine density in adult-born GCs, while their survival remained unaltered. Moreover, Ng-ko mice show an impaired odor-reward associative memory coupled with reduced expression of the activity-dependent transcription factor Zif268 in olfactory GCs. Overall, our data support a role for Ng in the molecular mechanisms underlying GC plasticity and the formation of olfactory associative memory.

Dynamic extrinsic pacing of the HOX clock in human axial progenitors controls motor neuron subtype specification

Rostro-caudal patterning of vertebrates depends on the temporally progressive activation of HOX genes within axial stem cells that fuel axial embryo elongation. Whether the pace of sequential activation of HOX genes, the 'HOX clock', is controlled by intrinsic chromatin-based timing mechanisms or by temporal changes in extrinsic cues remains unclear. Here, we studied HOX clock pacing in human pluripotent stem cell-derived axial progenitors differentiating into diverse spinal cord motor neuron subtypes. We show that the progressive activation of caudal HOX genes is controlled by a dynamic increase in FGF signaling. Blocking the FGF pathway stalled induction of HOX genes, while a precocious increase of FGF, alone or with GDF11 ligand, accelerated the HOX clock. Cells differentiated under accelerated HOX induction generated appropriate posterior motor neuron subtypes found along the human embryonic spinal cord. The pacing of the HOX clock is thus dynamically regulated by exposure to secreted cues. Its manipulation by extrinsic factors provides synchronized access to multiple human neuronal subtypes of distinct rostro-caudal identities for basic and translational applications.This article has an associated 'The people behind the papers' interview.

Propagation of α-Synuclein Strains within Human Reconstructed Neuronal Network

Reappraisal of neuropathological studies suggests that pathological hallmarks of Alzheimer’s disease and Parkinson’s disease (PD) spread progressively along predictable neuronal pathways in the human brain through unknown mechanisms. Although there is much evidence supporting the prion-like propagation and amplification of α-synuclein (α-Syn) in vitro and in rodent models, whether this scenario occurs in the human brain remains to be substantiated. Here we reconstructed in microfluidic devices corticocortical neuronal networks using human induced pluripotent stem cells derived from a healthy donor. We provide unique experimental evidence that different strains of human α-Syn disseminate in “wild-type” human neuronal networks in a prion-like manner. We show that two distinct α-Syn strains we named fibrils and ribbons are transported, traffic between neurons, and trigger to different extents, in a dose- and structure-dependent manner, the progressive accumulation of PD-like pathological hallmarks. We further demonstrate that seeded aggregation of endogenous soluble α-Syn affects synaptic integrity and mitochondria morphology.

•

Different α-Syn strains propagate within WT human iPSC-derived cortical neuronal networks

•

α-Syn strains differentially seed endogenous WT α-Syn forming LB/LN-like structures

•

Phospho-α-Syn endogenous aggregates resist degradation and accumulate in cytoplasm

•

Accumulation of phospho-α-Syn induces early neuronal dysfunctions

Interstitial Brachytherapy for Carcinomas of the Lower Lip. Results of Treatment

From 1973 to 1988 47 patients with previously untreated T1 and T2 squamous cell carcinomas of the lower lip received a definitive course of interstitial brachytherapy by iridium 192 wires. The disease stage was T1 in 21 cases (44.7 %) and T2 in 26, and NO in all cases except 2 of N1. Radiation therapy dose ranged between 6000 and 8000 cGy. Local control was obtained in 44 patients (93.6 %). Treatment failure in the neck was observed in 3 patients (6.7 %) The 5- and 10-year actuarial disease-free survival rates were 92% and 85%, respectively. A surgical salvage was attempted in 3 patients, with postoperative definitive control of the disease in 2. The 10-year actuarial overall survival was 95 %. The incidence of complications was acceptable (10.6% of mucosal necrosis). An excellent or good cosmetic result was obtained in 91.7% of patients.

Daily Low-dose Carboplatin and Standard Radiotherapy in Unresectable Head and Neck and Lung Cancers: A Pilot Study

A total of 14 patients with locally advanced and unresectable head and neck (SCCHN) or non small cell lung cancer were treated with a definitive course of radiation therapy with conventional fractionation and 30 mg/m2 carboplatin (CBDCA) given daily as an i.v. infusion during the 1st, 3rd, 5th and 7th weeks of the combined treatment. The planned tumor dose of at least 7000 cGy was reached in all SCCHN patients except 1 (6600 cGy). The 2 NSCLC patients received 6320 and 5980 cGy, respectively. The planned total CBDCA-dose of 600 mg/m2 was administered in all patients. No treatment delays were required in 10 patients. Interruptions for severe mucositis or myelosuppression occurred in 4 patients (28.6%), but in no case did the delay exceed 1 week. Complete response was obtained in 8 patients (57.1%); 7 of the 12 with SCCHN and 1 of the 2 with NSCLC. The other 6 patients achieved a partial response. Granulocytopenia of WHO grade 3 occurred in 1 patient; apart from vomiting and mucositis, toxicities above grade 2 were not observed.

CaMKIIα Expression Defines Two Functionally Distinct Populations of Granule Cells Involved in Different Types of Odor Behavior

Granule cells (GCs) in the olfactory bulb (OB) play an important role in odor information processing. Although they have been classified into various neurochemical subtypes, the functional roles of these subtypes remain unknown. We used in vivo two-photon Ca²⁺ imaging combined with cell-type-specific identification of GCs in the mouse OB to examine whether functionally distinct GC subtypes exist in the bulbar network. We showed that half of GCs express Ca²⁺/calmodulin-dependent protein kinase IIα (CaMKIIα⁺) and that these neurons are preferentially activated by olfactory stimulation. The higher activity of CaMKIIα⁺ neurons is due to the weaker inhibitory input that they receive compared to their CaMKIIα-immunonegative (CaMKIIα^-) counterparts. In line with these functional data, immunohistochemical analyses showed that 75%-90% of GCs expressing the immediate early gene cFos are CaMKIIα⁺ in naive animals and in mice that have been exposed to a novel odor and go/no-go operant conditioning, or that have been subjected to long-term associative memory and spontaneous habituation/dishabituation odor discrimination tasks. On the other hand, a perceptual learning task resulted in increased activation of CaMKIIα^- cells. Pharmacogenetic inhibition of CaMKIIα⁺ GCs revealed that this subtype is involved in habituation/dishabituation and go/no-go odor discrimination, but not in perceptual learning. In contrast, pharmacogenetic inhibition of GCs in a subtype-independent manner affected perceptual learning. Our results indicate that functionally distinct populations of GCs exist in the OB and that they play distinct roles during different odor tasks.

Fragile X Mental Retardation Protein and Dendritic Local Translation of the Alpha Subunit of the Calcium/Calmodulin-Dependent Kinase II Messenger RNA Are Required for the Structural Plasticity Underlying Olfactory Learning

BACKGROUND

In the adult brain, structural plasticity allowing gain or loss of synapses remodels circuits to support learning. In fragile X syndrome, the absence of fragile X mental retardation protein (FMRP) leads to defects in plasticity and learning deficits. FMRP is a master regulator of local translation but its implication in learning-induced structural plasticity is unknown.

METHODS

Using an olfactory learning task requiring adult-born olfactory bulb neurons and cell-specific ablation of FMRP, we investigated whether learning shapes adult-born neuron morphology during their synaptic integration and its dependence on FMRP. We used alpha subunit of the calcium/calmodulin-dependent kinase II (αCaMKII) mutant mice with altered dendritic localization of αCaMKII messenger RNA, as well as a reporter of αCaMKII local translation to investigate the role of this FMRP messenger RNA target in learning-dependent structural plasticity.

RESULTS

Learning induces profound changes in dendritic architecture and spine morphology of adult-born neurons that are prevented by ablation of FMRP in adult-born neurons and rescued by an metabotropic glutamate receptor 5 antagonist. Moreover, dendritically translated αCaMKII is necessary for learning and associated structural modifications and learning triggers an FMRP-dependent increase of αCaMKII dendritic translation in adult-born neurons.

CONCLUSIONS

Our results strongly suggest that FMRP mediates structural plasticity of olfactory bulb adult-born neurons to support olfactory learning through αCaMKII local translation. This reveals a new role for FMRP-regulated dendritic local translation in learning-induced structural plasticity. This might be of clinical relevance for the understanding of critical periods disruption in autism spectrum disorder patients, among which fragile X syndrome is the primary monogenic cause.

Transitory and activity-dependent expression of neurogranin in olfactory bulb tufted cells during mouse postnatal development

Neurogranin (Ng) is a brain-specific postsynaptic calmodulin-binding protein involved in synaptic activity-dependent plasticity. In the adult olfactory bulb (OB), Ng is expressed by a large population of GABAergic interneurons in the granule cell layer. We show here that, during postnatal development, Ng is also expressed by OB neurons in the superficial external plexiform layer (sEPL) and glomerular layer (GL). These Ng-positive neurons display morphological and neurochemical features of superficial and external tufted cells. Ng expression in these cells is transient during OB development: few elements express Ng at postnatal day (P) 5, increasing in number and reaching a peak at P10, then progressively decreasing. At P30, Ng is rarely detectable in these neurons. Ng expression in developing tufted cells is also modulated at the cellular level: at earlier stages, Ng labeling is distributed throughout the cell body and dendritic arborization in the GL, but, at P20, when the glomerular circuits are fully matured, Ng becomes restricted to the soma and proximal portion of tufted cell apical dendrites. We show that olfactory deprivation at early postnatal stages induces a strong increase in Ng-positive tufted cells from P10 to P20, whereas no changes have been observed following olfactory deprivation in adult mice. These findings demonstrate that Ng expression in sEPL-GL is restricted to developmental stages and indicate its activity-dependent regulation in a time window critical for glomerular circuit development, suggesting a role for Ng in maturation and dendritic remodeling of tufted cells.

A role for dendritic translation of CaMKIIα mRNA in olfactory plasticity

Local protein synthesis in dendrites contributes to the synaptic modifications underlying learning and memory. The mRNA encoding the α subunit of the calcium/calmodulin dependent Kinase II (CaMKIIα) is dendritically localized and locally translated. A role for CaMKIIα local translation in hippocampus-dependent memory has been demonstrated in mice with disrupted CaMKIIα dendritic translation, through deletion of CaMKIIα 3′UTR. We studied the dendritic localization and local translation of CaMKIIα in the mouse olfactory bulb (OB), the first relay of the olfactory pathway, which exhibits a high level of plasticity in response to olfactory experience. CaMKIIα is expressed by granule cells (GCs) of the OB. Through in situ hybridization and synaptosome preparation, we show that CaMKIIα mRNA is transported in GC dendrites, synaptically localized and might be locally translated at GC synapses. Increases in the synaptic localization of CaMKIIα mRNA and protein in response to brief exposure to new odors demonstrate that they are activity-dependent processes. The activity-induced dendritic transport of CaMKIIα mRNA can be inhibited by an NMDA receptor antagonist and mimicked by an NMDA receptor agonist. Finally, in mice devoid of CaMKIIα 3′UTR, the dendritic localization of CaMKIIα mRNA is disrupted in the OB and olfactory associative learning is severely impaired. Our studies thus reveal a new functional modality for CaMKIIα local translation, as an essential determinant of olfactory plasticity.

From progenitors to integrated neurons: role of neurotransmitters in adult olfactory neurogenesis

Adult neurogenesis is due to the persistence of pools of constitutive stem cells able to give rise to a progeny of proliferating progenitors. In rodents, adult neurogenic niches have been found in the subventricular zone (SVZ) along the lateral ventricles and in the subgranular zone of the dentate gyrus in the hippocampus. SVZ progenitors undergo a unique process of tangential migration from the lateral ventricle to the olfactory bulb (OB) where they differentiate mainly into GABAergic interneurons in the granule and glomerular layers. SVZ progenitor proliferation, migration and differentiation into fully integrated neurons, are strictly related processes regulated by complex interactions between cell intrinsic and extrinsic influences. Numerous observations demonstrate that neurotrasmitters are involved in all steps of the adult neurogenic process, but the understanding of their role is hampered by their intricate mechanism of action and by the highly complex network in which neurotransmitters work. By considering the three main steps of olfactory adult neurogenesis (proliferation, migration and integration), this review will discuss recent advances in the study of neurotransmitters, highlighting the regulatory mechanisms upstream and downstream their action.

Expression and localization of the calmodulin-binding protein neurogranin in the adult mouse olfactory bulb

Neurogranin (Ng) is a brain-specific postsynaptic protein involved in activity-dependent synaptic plasticity through modulation of Ca(2+)/calmodulin (CaM)-dependent signal transduction in neurons. In this study, using biochemical and immunohistochemical approaches, we demonstrate Ng expression in the adult mouse olfactory bulb (OB), the first relay station in odor information processing. We show that Ng is principally associated with the granule cell layer (GCL), which is composed of granule cell inhibitory interneurons. This cell type is continuously renewed during adult life and plays a key role in OB circuits, integrating and modulating the activity of mitral/tufted cells. Our results indicate that Ng localizes in the soma and dendrites of a defined subpopulation of mature GABAergic granule cells, enriched in the deep portion of the GCL. Ng-immunopositive cells largely coexpress the Ca(+)/CaM-dependent kinase IV (CaMKIV), a downstream protein of CaM signaling cascade, whereas no colocalization was observed between Ng and the calcium-binding protein calretinin. Finally, we demonstrate that adult neurogenesis contributes to the Ng-expressing population, with more newly generated Ng-positive cells integrated in the deep GCL. Together, these results provide a new specific neurochemical marker to identify a subpopulation of olfactory granule cells and suggest possible functional implications for Ng in OB plasticity mechanisms.

In vitro and in vivo models for the evaluation of new inhibitors of human steroid sulfatase, devoid of residual estrogenic activity

The goal of our research project is to develop a new class of orally active drugs, estrone sulfatase inhibitors, for the treatment of estrogen-dependent (receptor positive) breast cancer. Several compounds were synthesized and their pharmacological potencies explored. Based on encouraging preliminary results, three of them, TX 1299, TX 1492 and TX 1506 were further studied in vitro as well as in vivo. They proved to be strong inhibitors of estrone sulfatase when measured on the whole human JEG-3 choriocarcinoma and MCF-7 breast cancer cells and their IC(50)s found to be in the range of known standard inhibitors. Their residual estrogenic activity was checked as negative in the test of induction of alkaline phosphatase (APase) activity in whole human endometrial adenocarcinoma Ishikawa cells. In addition, their effect on aromatase activity in JEG-3 cells was also examined, since the goal of inhibiting both sulfatase and aromatase activities appears very attractive. However, it has been unsuccessful so far. Then, in vivo potencies of TX 1299, the lead compound in our chemical series, were evaluated in comparison with 6,6,7-COUMATE, a non-steroidal standard, in two different rat models and by oral route. First, the absence of any residual estrogenic activity for these compounds was checked in the uterotrophic model in prepubescent female rats. Second, antiuterotrophic activity in adult ovariectomized rat supplemented with estrone sulfate (E(1)S), showed that both compounds were potent inhibitors, the power of TX 1299 relative to 6,6,7-COUMATE being around 80%. This assay was combined with uterine sulfatase level determination and confirmed the complete inhibition of this enzyme within the target organ. Preliminary studies indicated that other non-steroid compounds in the Théramex series were potent in vitro and in vivo inhibitors of estrone sulfatase in rats and further studies are in progress.

Small cell carcinoma of the esophagus

Small cell carcinoma of the esophagus (SCEC) is a rare tumor with its particular biologic features, distinct from squamous and glandular carcinoma of esophagus. Although initial symptoms can be similar (with metastatic dissemination and paraneoplastic syndromes at presentation more frequent in SCEC), differences in age and sex distribution, tumor location, radiological and endoscopic findings, clinical course and prognosis have been observed between SCEC and other esophageal malignancies. SCEC should be considered a systemic disease, and by analogy to bronchogenic small cell carcinoma, multimodality approach including chemotherapy is recommended. In patients with limited disease, irradiation or surgery should be offered after induction chemotherapy to manage local disease. However, optimal treatment schedule has not yet been defined. In the future, registration of all SCEC cases and careful analysis of prognostic factors in the larger multi-institutional series could contribute to further progress in treatment outcome.

[Role of radiotherapy in the combined treatment of invasive cancer of the vulva]

The authors review the literature on the different combinations of radiotherapy with chemotherapy and surgery with the aim of giving a state of art on the role of combined multimodality treatment of invasive vulvar carcinoma. From the data of the recent literature it appears that radiation integrated with surgery and chemotherapy can play an important role in reducing the risk of postoperative locoregional failure in patients with advanced primary or nodal disease and avoiding exenteration in patients with disease involving the anus or proximal urethra. This integrated multimodality therapy is a promising approach in the treatment of invasive vulvar carcinoma but further exploration in a larger number of patients is needed before giving consolidated data applicable in routine oncological clinical practice.

[Survival and recurrence of endometrial adenocarcinoma]

444 endometrial carcinomas were retrospectively reviewed. Disease-free survival (DFS) was 83.6% at five years and 80.5% at ten years. 349 T1 cancers were treated by TAH-BSO and post-operative irradiation; 22.6% of them were over-staged. DFS ranged from 100% to 91% in 270 low-risk T1 patients, dropping to 84% in intermediate risk patients and to 44% in high-risk patients. DFS was 93% and 66% in the patients overstaged as pT2 and pT3, respectively; it was 82% for ovarian spread and 45% for pelvic peritoneum/parametrium invasion. T2-T3 patients were treated with preoperative irradiation and bilateral hysterectomy. DFS was 90.5% vs. 72.2% and 2/2 vs. 3/7 when the lesion was understaged. The results of irradiation were similar to literature data, but 53% of patients (all in poor general conditions and/or very old) died from associated diseases. Relapses were observed in 13.6% of cases (62/444 patients); 29 (6%) were local recurrences and 33 (7.6%) were distant metastases, which correlated well with recurrences and 33 (7.6%) were distant metastases, which correlated well with risk factors. Severe complication (G3) were observed in 6.3% of cases.

Concomitant radiotherapy and daily low-dose carboplatin in locally advanced, unresectable head and neck cancer. Definitive results of a phase I-II study

The combination of daily low-dose carboplatin and radiotherapy was studied in 55 patients with inoperable head and neck cancer. All patients were planned to receive 70 Gy plus carboplatin i.v. daily, 45-60 min before radiotherapy. A starting schedule of 30 mg/m2 on days 1 through 5, weeks 1, 3, 5 and 7 was administered to 17 patients; an escalating daily dose, up to 55 mg/m2, was given to 38 additional patients. Up to a daily dose of 45 mg/m2, only 4.4% of the patients developed grade 3 leukopenia; on the contrary, grade 3 and 4 leukopenia was seen in 62.5% of patients receiving 50 mg/m2 or more. Mucositis was the major nonhaematologic toxicity and seemed to be dose-dependent. At the end of the loco-regional treatment there were 33 (61.1%) CR and 17 PR; the most effective total carboplatin dose seemed to be 40-45 mg/m2. After surgical salvage the number of CRs increased to 37 (68.5%). One- and 2-year loco-regional control rates were 64% and 53% respectively. One- and 2-year actuarial survival rates were 71% and 53% respectively; the corresponding rates of disease-free survival were 60% and 43%. There was a strong correlation nodal status and both survival and disease-free survival.