Specific Cellular Properties Research Articles

Research progress of the inferior colliculus: from Neuron, neural circuit to auditory disease

The auditory midbrain, also known as the inferior colliculus (IC), serves as a crucial hub in the auditory pathway. Comprising diverse cell types, the IC plays a pivotal role in various auditory functions, including sound localization, auditory plasticity, sound detection, and sound-induced behaviors. Notably, the IC is implicated in several auditory central disorders, such as tinnitus, age-related hearing loss, autism and Fragile X syndrome. Accurate classification of IC neurons is vital for comprehending both normal and dysfunctional aspects of IC function. Various parameters, including dendritic morphology, neurotransmitter synthesis, potassium currents, biomarkers, and axonal targets, have been employed to identify distinct neuron types within the IC. However, the challenge persists in effectively classifying IC neurons into functional categories due to the limited clustering capabilities of most parameters. Recent studies utilizing advanced neuroscience technologies have begun to shed light on biomarker-based approaches in the IC, providing insights into specific cellular properties and offering a potential avenue for understanding IC functions. This review focuses on recent advancements in IC research, spanning from neurons and neural circuits to aspects related to auditory diseases.

Generation of a symmetrical trispecific NK cell engager based on a two-in-one antibody.

To construct a trispecific IgG-like antibody at least three different binding moieties need to be combined, which results in a complex architecture and challenging production of these molecules. Here we report for the first time the construction of trispecific natural killer cell engagers based on a previously reported two-in-one antibody combined with a novel anti-CD16a common light chain module identified by yeast surface display (YSD) screening of chicken-derived immune libraries. The resulting antibodies simultaneously target epidermal growth factor receptor (EGFR), programmed death-ligand 1 (PD-L1) and CD16a with two Fab fragments, resulting in specific cellular binding properties on EGFR/PD-L1 double positive tumor cells and a potent ADCC effect. This study paves the way for further development of multispecific therapeutic antibodies derived from avian immunization with desired target combinations, valencies, molecular symmetries and architectures.

A Generic Strategy to Generate Bifunctional Two-in-One Antibodies by Chicken Immunization.

Various formats of bispecific antibodies exist, among them Two-in-One antibodies in which each Fab arm can bind to two different antigens. Their IgG-like architecture accounts for low immunogenicity and also circumvents laborious engineering and purification steps to facilitate correct chain pairing. Here we report for the first time the identification of a Two‐in‐One antibody by yeast surface display (YSD) screening of chicken-derived immune libraries. The resulting antibody simultaneously targets the epidermal growth factor receptor (EGFR) and programmed death‐ligand 1 (PD-L1) at the same Fv fragment with two non-overlapping paratopes. The dual action Fab is capable of inhibiting EGFR signaling by binding to dimerization domain II as well as blocking the PD-1/PD-L1 interaction. Furthermore, the Two-in-One antibody demonstrates specific cellular binding properties on EGFR/PD-L1 double positive tumor cells. The presented strategy relies solely on screening of combinational immune-libraries and obviates the need for any additional CDR engineering as described in previous reports. Therefore, this study paves the way for further development of therapeutic antibodies derived from avian immunization with novel and tailor-made binding properties.

Abstract 14265: The Role Of Vesicle-incorporated Long Noncoding RNA H19 In Cardiovascular Disease

Background: Recent studies have demonstrated that pathogenesis of cardiovascular disease (CVD) includes higher levels of circulating extracellular vesicles (EVs). Those EVs can contain different types of cargoes including long noncoding RNAs (LncRNAs). Here we aim to elucidate the cellular function and mechanism of action of LncRNA H19 with particular interest in EV-mediated intercellular communication. Methods and Results: Loss of function of H19 was performed in vitro using RNA interference in vascular endothelial cells (ECs). After H19 loss of function, various assays were conducted to assess specific cellular properties and functions in both EV-donor and recipient cells. The cellular properties in terms of viability and apoptosis as well as the cellular functions regarding migration, proliferation, and angiogenesis were impaired in EV-donor cells. Intriguingly, both cellular properties and functions were improved in EV-recipient cells. Since our results indicated that the angiogenic sprouting was impaired in cells after knockdown of H19, we want to perform angiogenesis array to identify dysregulated genes that are involved in angiogenesis. To unravel the molecular mechanism of H19 further, we sought to identify binding partners of H19 to unveil how vesicle-incorporated H19 exerts it specific functions in CVDs and cardiovascular cells in vitro . Conclusion: Our data suggests that vesicular transport of H19 regulates the cellular properties and function of target ECs. Further investigation is required to identify specific H19 molecular mechanism of action that plays a crucial role in cardiovascular cells and disease. Figure 1: Schematic representation of EV-mediated intercellular transfer of lncRNA H19. LncRNA H19 can be transferred to the target cell via extracellular vesicles (EVs). Studies showed that H19 can exploit different regulatory functions endothelial cells.

Myeloid Progenitors of Defined Features Provide Permissiveness to Leukemic Transformation

The conventional view of oncogenesis posits that driver mutations, when present in appropriate cell types, initiate malignant transformation. At the apex of the differentiation hierarchy, stem cells, such as hematopoietic stem cells, have been suggested to be the cell-of-origin for a variety of hematopoietic malignancies. However, since the mutation bearing hematopoietic stem cells can differentiate to give rise to downstream progeny, it suggests the possibility that some of the downstream cells be the relevant cell-of-origin permitting malignant transformation. Given that cancer cell-of-origin has been a product of logic deduction evading rigorous experimentation, whether and how their unique cellular properties, if any, contribute to transformation remain undetermined.To experimentally define the key properties of the cell-of-origin permissive to oncogenic transformation, we constructed a doxycycline (Dox) inducible MLL-AF9 knock-in mouse model, which allows precise temporal control of oncogene expression in desired hematopoietic cells, in vitro and in vivo . Whole body induction by Dox led to 100% lethality due to acute myeloid leukemia (AML) within 6-8 weeks, while the un-induced littermates remained healthy, confirming the inducibility and potency of the MLL-AF9 oncogene. To minimize the differences contributed by cellular differentiation stages and to focus solely on the contributions by specific cellular properties, we narrowed our analysis on a phenotypically homogeneous population, the granulocyte-macrophage progenitors (GMPs), which have been shown to be critically important in supporting leukemic development (Ugale et al ., 2014, Cell Reports; Ye et al ., 2015, Cell Stem Cell). We found that although MLL-AF9 expression can be induced in all GMPs, only a subset (~25%) of them is permissive to transformation. These results prompted us to investigate the underlying cellular and molecular properties that enable oncogenic transformation.Inspired by our earlier work demonstrating that the cell fate plasticity of GMPs is related to their rapid cell cycle behavior (Guo et al ., 2014, Cell), we tested whether the rapid proliferation of GMPs underlies their permissiveness to oncogenic transformation. If so, transformation potential should be enriched in the faster-proliferating GMP subsets. To test this possibility, we designed single cell assays to investigate the transformation efficiencies of GMPs with regard to their cell cycle speeds. Specifically, the intrinsic cell cycle speed was measured within 24 hours of Dox addition, and transformation status of hundreds of individual GMPs was determined by methylcellulose colony formation assay. Within the first 24 hours of Dox addition, the cell cycle speed remained unchanged, reflecting the intrinsic cell cycle kinetics, rather than a proliferative response to oncogene expression. Our results show that the faster a GMP divides, the more likely it transforms in response to MLL-AF9 expression. Strikingly, most GMPs that can divide more than 3 times within 24 hours are transformed. These data indicate the fastest cycling GMPs provide the oncogene with a permissive cellular context to exert its function. Furthermore, prospectively isolated faster cycling GMPs enriched for transformed colony formation in vitro, and induced earlier lethal AML in vivo . Importantly, transient deceleration of GMPs for 48 hours by low-dose CDK4/6 inhibitor, Palbociclib, significantly reduced transformation efficiency by ~ 60%. Taken together, these results demonstrate that MLL-AF9 initiated transformation is dependent on specific cellular properties which are associated with a rapid cell cycle. Genomic analyses of the transformation-permissive GMPs, using non-permissive GMPs as controls, are being performed to define the permissiveness in molecular details, on both transcriptional and epigenetic levels. DisclosuresNo relevant conflicts of interest to declare.

Tissue on the Transferred Coracoid Graft After Latarjet Procedure: Histological and Morphological Findings

Background: Anterior shoulder instability is a debilitating condition that can require stabilization via a Latarjet procedure. Purpose: The aim of this study was to characterize the histological composition of the articular-sided surface of the coracoid bone graft after Latarjet procedure. Specific features of cells isolated from the coracoid and graft tissues were assessed. Study Design: Case series; Level of evidence, 4. Methods: Tissue samples were harvested from 9 consecutive patients undergoing arthroscopic debridement and screw removal after arthroscopic or open Latarjet procedure. Tissues were processed histologically. In 2 patients, the samples were analyzed to assess specific cellular properties. Results: Safranin O staining indicated that glenoid tissues contained variable amounts of glycosaminoglycan (GAG) and round chondrocytic cells mainly organized in clusters. Graft tissues contained less GAG and were more cellular but were not organized in clusters and had variable morphological features. An association appeared to exist between the cartilage quality of glenoid tissues and that of the graft tissues. Cells isolated from glenoid and graft tissues exhibited similar proliferation capacity. Conclusion: The results of our analysis show that cells located at the articular-sided surface of transferred coracoid grafts demonstrate fibrocartilaginous properties and may have the capacity for chondral proliferation. Further studies are needed to confirm this observation and future application.

Brain structure and neurological and behavioural functioning in infants born preterm.

To examine: (1) relationships between brain structure, and concurrently assessed neurological and behavioural functioning, in infants born preterm at term-equivalent age (TEA; approximately 38-44wks); and (2) whether brain structure-function relationships differ between infants born very (24-29wks) and moderate-late (32-36wks) preterm. A total of 257 infants (91 very preterm, 166 moderate-late preterm; 120 males, 137 females) had structural magnetic resonance imaging (MRI) and neurological and behavioural assessments (Prechtl's general movements assessment, Neonatal Intensive Care Unit Network Neurobehavioral Scale [NNNS] and Hammersmith Neonatal Neurological Examination [HNNE]). Two hundred and sixty-three infants (90 very preterm, 173 moderate-late preterm; 131 males, 132 females) had diffusion MRI and assessments. Associations were investigated between assessment scores and global brain volumes using linear regressions, regional brain volumes using Voxel-Based Morphometry, and white matter microstructure using Tract-Based Spatial Statistics. Suboptimal scores on some assessments were associated with lower fractional anisotropy and/or higher axial, radial, and mean diffusivities in some tracts: NNNS attention and reflexes, and HNNE total score and tone, were associated with the corpus callosum and optic radiation; NNNS quality of movement with the corona radiata; HNNE abnormal signs with several major tracts. Brain structure-function associations generally did not differ between the very and moderate-late preterm groups. White matter microstructural alterations may be associated with suboptimal neurological and behavioural performance in some domains at TEA in infants born preterm. Brain structure-function relationships are similar for infants born very preterm and moderate-late preterm. Brain volume is not related to neurological/behavioural function in infants born preterm at term. White matter microstructure is related to some neurological/behavioural domains at term. Brain-behaviour relationships are generally similar for infants born very preterm and moderate-late preterm.

Modeling signaling‐dependent pluripotency with Boolean logic to predict cell fate transitions

Pluripotent stem cells (PSCs) exist in multiple stable states, each with specific cellular properties and molecular signatures. The mechanisms that maintain pluripotency, or that cause its destabilization to initiate development, are complex and incompletely understood. We have developed a model to predict stabilized PSC gene regulatory network (GRN) states in response to input signals. Our strategy used random asynchronous Boolean simulations (R‐ABS) to simulate single‐cell fate transitions and strongly connected components (SCCs) strategy to represent population heterogeneity. This framework was applied to a reverse‐engineered and curated core GRN for mouse embryonic stem cells (mESCs) and used to simulate cellular responses to combinations of five signaling pathways. Our simulations predicted experimentally verified cell population compositions and input signal combinations controlling specific cell fate transitions. Extending the model to PSC differentiation, we predicted a combination of signaling activators and inhibitors that efficiently and robustly generated a Cdx2+Oct4− cells from naïve mESCs. Overall, this platform provides new strategies to simulate cell fate transitions and the heterogeneity that typically occurs during development and differentiation.

Emergence of Narrowband High Frequency Oscillations from Asynchronous, Uncoupled Neural Firing.

Previous experimental studies have demonstrated the emergence of narrowband local field potential oscillations during epileptic seizures in which the underlying neural activity appears to be completely asynchronous. We derive a mathematical model explaining how this counterintuitive phenomenon may occur, showing that a population of independent, completely asynchronous neurons may produce narrowband oscillations if each neuron fires quasi-periodically, without requiring any intrinsic oscillatory cells or feedback inhibition. This quasi-periodicity can occur through cells with similar frequency-current ([Formula: see text]-[Formula: see text]) curves receiving a similar, high amount of uncorrelated synaptic noise. Thus, this source of oscillatory behavior is distinct from the usual cases (pacemaker cells entraining a network, or oscillations being an inherent property of the network structure), as it requires no oscillatory drive nor any specific network or cellular properties other than cells that repetitively fire with continual stimulus. We also deduce bounds on the degree of variability in neural spike-timing which will permit the emergence of such oscillations, both for action potential- and postsynaptic potential-dominated LFPs. These results suggest that even an uncoupled network may generate collective rhythms, implying that the breakdown of inhibition and high synaptic input often observed during epileptic seizures may generate narrowband oscillations. We propose that this mechanism may explain why so many disparate epileptic and normal brain mechanisms can produce similar high frequency oscillations.

Adult mouse cortical cell taxonomy revealed by single cell transcriptomics.

Nervous systems are composed of various cell types, but the extent of cell type diversity is poorly understood. Here, we construct a cellular taxonomy of one cortical region, primary visual cortex, in adult mice based on single cell RNA-sequencing. We identify 49 transcriptomic cell types including 23 GABAergic, 19 glutamatergic and seven non-neuronal types. We also analyze cell-type specific mRNA processing and characterize genetic access to these transcriptomic types by many transgenic Cre lines. Finally, we show that some of our transcriptomic cell types display specific and differential electrophysiological and axon projection properties, thereby confirming that the single cell transcriptomic signatures can be associated with specific cellular properties.

Asynchronous Rate Chaos in Spiking Neuronal Circuits.

The brain exhibits temporally complex patterns of activity with features similar to those of chaotic systems. Theoretical studies over the last twenty years have described various computational advantages for such regimes in neuronal systems. Nevertheless, it still remains unclear whether chaos requires specific cellular properties or network architectures, or whether it is a generic property of neuronal circuits. We investigate the dynamics of networks of excitatory-inhibitory (EI) spiking neurons with random sparse connectivity operating in the regime of balance of excitation and inhibition. Combining Dynamical Mean-Field Theory with numerical simulations, we show that chaotic, asynchronous firing rate fluctuations emerge generically for sufficiently strong synapses. Two different mechanisms can lead to these chaotic fluctuations. One mechanism relies on slow I-I inhibition which gives rise to slow subthreshold voltage and rate fluctuations. The decorrelation time of these fluctuations is proportional to the time constant of the inhibition. The second mechanism relies on the recurrent E-I-E feedback loop. It requires slow excitation but the inhibition can be fast. In the corresponding dynamical regime all neurons exhibit rate fluctuations on the time scale of the excitation. Another feature of this regime is that the population-averaged firing rate is substantially smaller in the excitatory population than in the inhibitory population. This is not necessarily the case in the I-I mechanism. Finally, we discuss the neurophysiological and computational significance of our results.

Recombinant disintegrin domain of human ADAM9 inhibits migration and invasion of DU145 prostate tumor cells

One of the most important features of malignant cells is their capacity to invade adjacent tissues and metastasize to distant organs. This process involves the creation, by tumor and stroma cells, of a specific microenvironment, suitable for proliferation, migration and invasion of tumor cells. The ADAM family of proteins has been involved in these processes. This work aimed to investigate the role of the recombinant disintegrin domain of the human ADAM9 (rADAM9D) on the adhesive and mobility properties of DU145 prostate tumor cells. rADAM9D was able to support DU145 cell adhesion, inhibit the migration of DU145 cells, as well as the invasion of this cell line through matrigel in vitro. Overall this work demonstrates that rADAM9D induces specific cellular migratory properties when compared with different constructs having additional domains, specially those of metalloproteinase and cysteine-rich domains. Furthermore, we showed that rADAM9D was able to inhibit cell adhesion, migration and invasion mainly through interacting with α6β1 in DU145 tumor cell line. These results may contribute to the development of new therapeutic strategies for prostate cancer.

Analysis of signal processing in vestibular circuits with a novel light-emitting diodes-based fluorescence microscope.

Optical visualization of neural network activity is limited by imaging system-dependent technical tradeoffs. To overcome these constraints, we have developed a powerful low-cost and flexible imaging system with high spectral variability and unique spatio-temporal precision for simultaneous optical recording and manipulation of neural activity of large cell groups. The system comprises eight high-power light-emitting diodes, a camera with a large metal-oxide-semiconductor sensor and a high numerical aperture water-dipping objective. It allows fast and precise control of excitation and simultaneous low noise imaging at high resolution. Adjustable apertures generated two independent areas of variable size and position for simultaneous optical activation and image capture. The experimental applicability of this system was explored in semi-isolated preparations of larval axolotl (Ambystoma mexicanum) with intact inner ear organs and central nervous circuits. Cyclic galvanic stimulation of semicircular canals together with glutamate- and γ-aminobutyric acid (GABA)-uncaging caused a corresponding modulation of Ca(2+) transients in central vestibular neurons. These experiments revealed specific cellular properties as well as synaptic interactions between excitatory and inhibitory inputs, responsible for spatio-temporal-specific sensory signal processing. Location-specific GABA-uncaging revealed a potent inhibitory shunt of vestibular nerve afferent input in the predominating population of tonic vestibular neurons, indicating a considerable impact of local and commissural inhibitory circuits on the processing of head/body motion-related signals. The discovery of these previously unknown properties of vestibular computations demonstrates the merits of our novel microscope system for experimental applications in the field of neurobiology.

Cofilin-2 Controls Actin Filament Length in Muscle Sarcomeres

ADF/cofilins drive cytoskeletal dynamics by promoting the disassembly of "aged" ADP-actin filaments. Mammals express several ADF/cofilin isoforms, but their specific biochemical activities and cellular functions have not been studied in detail. Here, we demonstrate that the muscle-specific isoform cofilin-2 promotes actin filament disassembly in sarcomeres to control the precise length of thin filaments in the contractile apparatus. In contrast to other isoforms, cofilin-2 efficiently binds and disassembles both ADP- and ATP/ADP-Pi-actin filaments. We mapped surface-exposed cofilin-2-specific residues required for ATP-actin binding and propose that these residues function as an "actin nucleotide-state sensor" among ADF/cofilins. The results suggest that cofilin-2 evolved specific biochemical and cellular properties that allow it to control actin dynamics in sarcomeres, where filament pointed ends may contain a mixture of ADP- and ATP/ADP-Pi-actin subunits. Our findings also offer a rationale for why cofilin-2 mutations in humans lead to myopathies.

Active contractions in single suspended epithelial cells

Investigations of active contractions in tissue cells to date have been focused on cells that exert forces via adhesion sites to substrates or to other cells. In this study we show that also suspended epithelial cells exhibit contractility, revealing that contractions can occur independently of focal adhesions. We employ the Optical Stretcher to measure adhesion-independent mechanical properties of an epithelial cell line transfected with a heat-sensitive cation channel. During stretching the heat transferred to the ion channel causes a pronounced Ca(2+) influx through the plasma membrane that can be blocked by adequate drugs. This way the contractile forces in suspended cells are shown to be partially triggered by Ca(2+) signaling. A phenomenological mathematical model is presented, incorporating a term accounting for the active stress exerted by the cell, which is both necessary and sufficient to describe the observed increase in strain when the Ca(2+) influx is blocked. The median and the shape of the strain distributions depend on the activity of the cells. Hence, it is unlikely that they can be described by a simple Gaussian or log normal distribution, but depend on specific cellular properties such as active contractions. Our results underline the importance of considering activity when measuring cellular mechanical properties even in the absence of measurable contractions. Thus, the presented method to quantify active contractions of suspended cells offers new perspectives for a better understanding of cellular force generation with possible implications for medical diagnosis and therapy.

Controlling and Assessing the Surface Display of Cell-Binding Domains on Magnetite Conjugated Fluorescent Liposomes

Biological systems provide us with a diverse source of peptide-based ligands for cellular adhesion. Controlling and assessing the ligand surface density as well as tailoring the surface chemistry to have specific cellular adhesion properties are important in biomaterials design. In the following work, we provide a means for displaying peptide-based ligands on magnetic liposomes in which the surface density and chemistry may be controlled. Simultaneously, the conjugated vesicles provide a fluorescent signal for examining steric hindrance among surface ligands. In addition, the inherent magnetic and fluorescence features of this system revealed potential for magnet-based cell isolation and fluorescent labeling of adhered cells, respectively. Adhered cells were found to remain viable and proliferative, thereby allowing them to be used for subsequent evaluation. In a specific demonstration, we control the density of fibronectin-mimetic ligands on the polydiacetylene liposome surfaces. We find that steric limitation occurring at over 20% surface density result in decreased cell adhesion, in accord with related techniques. The magnetic-liposome system offers the means for not only separating cells adhered to the biomaterial, but also providing the ability to control and assess the biomaterial surface. This may prove particularly useful for examining combinations of peptide-based ligands or for evaluating the molecular-level ligand accessibility and its effect on cell attachment to a biomaterial surface.

Highlighted Ca2+ imaging with a genetically encoded ‘caged’ indicator

Genetically encoded fluorescent indicators for bioimaging are powerful tools for visualizing biological phenomena in specified cell types or cellular compartments. However, available gene promoters or localization sequences are not applicable for visualizing all expression events. Furthermore, a visualization technique focusing on single cells or cellular compartments is required for characterizing specific cellular properties including individuality of cells in the cell population. To address these limitations, we developed a genetically encoded caged Ca2+ indicator for which expression timing and location could be controlled. This indicator, PA-TNXL, comprises a Ca2+-binding protein and troponin between a photoactivatable FRET donor (PA-GFP) and a FRET quencher (dim variant of YFP). Ultraviolet irradiation activates the FRET Ca2+ indicator. Using this indicator, we successfully imaged Ca2+ dynamics in a given set of HeLa cells and cultured hippocampal neurons. This technology can be applied for developing other photoactivatable indicators, thereby opening a new area of biological research.

Emerging role of crystallin proteins in retinal neurodegenerative diseases

T specific goal of this project is to better characterize the specific and respective roles of αA-and αB-crystallin, the two members of the α-crystallin sub-family in the retina and how diabetes but also retinal traumas affect them. Alpha-crystallins are important, conserved, intrinsic stress response proteins in the retina. We previously demonstrated that they are upregulated in diabetic conditions and that their biochemical properties are affected by diabetes, however their exact implication and role in retinal function and how it is affected by retinal diseases or pathological conditions remained to be clarified. Specific biochemical and cellular properties of α-crystallins in the retina were analyzed in animal models as well as human patient samples. In addition α-crystallins knockout mice were used to dissect the respective functions of α-crystallins in the retina in control and pathological conditions. Retinal function was analyzed using non-invasive methods such as optical coherence tomography and electroretinographic recordings whereas specific retinal cell survival was analyzed using cell-death assay and immunohistochemistry. This work clearly demonstrates the independent and specific respective roles of αA-and αB-crystallin in the retina in the context of chronic disease conditions such as diabetes or more acute conditions including retinal trauma. αA-and αB-crystallin proteins clearly display a different localization in the retina as well as different impact on retinal function in neurodegenerative conditions. This study demonstrates how understanding retinal intrinsic protective mechanisms could be critical in order to prevent loss of vision in patients with both acute and chronic retinal conditions but might require different strategies.

Targeted Molecular Imaging.

This article reviews Targeted Molecular Imaging. by Michael J. Welch, William C. Eckelman, William R. Hendee , Taylor & Francis Group, Boca Raton, FL, 2012, 388 pp. Price: $169.95. ISBN: 9781439841952 (hardcover).

Automated Parameter Estimation of the Hodgkin-Huxley Model Using the Differential Evolution Algorithm: Application to Neuromimetic Analog Integrated Circuits

We propose a new estimation method for the characterization of the Hodgkin-Huxley formalism. This method is an alternative technique to the classical estimation methods associated with voltage clamp measurements. It uses voltage clamp type recordings, but is based on the differential evolution algorithm. The parameters of an ionic channel are estimated simultaneously, such that the usual approximations of classical methods are avoided and all the parameters of the model, including the time constant, can be correctly optimized. In a second step, this new estimation technique is applied to the automated tuning of neuromimetic analog integrated circuits designed by our research group. We present a tuning example of a fast spiking neuron, which reproduces the frequency-current characteristics of the reference data, as well as the membrane voltage behavior. The final goal of this tuning is to interconnect neuromimetic chips as neural networks, with specific cellular properties, for future theoretical studies in neuroscience.