Michele Papa

Professor of Anatomy

Name Michele
Surname Papa
Institution Università degli Studi della Campania Luigi Vanvitelli
E-Mail michele.papa@unicampania.it
Address II Division of Neurology & Center fo Rare Diseases Department of Medical Surgical, Neurological, Metabolic Sciences, and Aging, University of Campania Luigi Vanvitelli, Edificio 10 Via Sergio Pansini, 580131 Naples, Italy


  • Differentiation by nerve growth factor (NGF) involves mechanisms of crosstalk between energy homeostasis and mitochondrial remodeling.

    Publication Date: 09/03/2018 on Cell death & disease
    by Martorana F, Gaglio D, Bianco MR, Aprea F, Virtuoso A, Bonanomi M, Alberghina L, Papa M, Colangelo AM
    DOI: 10.1038/s41419-018-0429-9

    Neuronal differentiation involves extensive modification of biochemical and morphological properties to meet novel functional requirements. Reorganization of the mitochondrial network to match the higher energy demand plays a pivotal role in this process. Mechanisms of neuronal differentiation in response to nerve growth factor (NGF) have been largely characterized in terms of signaling, however, little is known about its impact on mitochondrial remodeling and metabolic function. In this work, we show that NGF-induced differentiation requires the activation of autophagy mediated by Atg9b and Ambra1, as it is disrupted by their genetic knockdown and by autophagy blockers. NGF differentiation involves the induction of P-AMPK and P-CaMK, and is prevented by their pharmacological inhibition. These molecular events correlate with modifications of energy and redox homeostasis, as determined by ATP and NADPH changes, higher oxygen consumption (OCR) and ROS production. Our data indicate that autophagy aims to clear out exhausted mitochondria, as determined by enhanced localization of p62 and Lysotracker-red to mitochondria. In addition, we newly demonstrate that NGF differentiation is accompanied by increased mitochondrial remodeling involving higher levels of fission (P-Drp1) and fusion proteins (Opa1 and Mfn2), as well as induction of Sirt3 and the transcription factors mtTFA and PPARγ, which regulate mitochondria biogenesis and metabolism to sustain increased mitochondrial mass, potential, and bioenergetics. Overall, our data indicate a new NGF-dependent mechanism involving mitophagy and extensive mitochondrial remodeling, which plays a key role in both neurogenesis and nerve regeneration.

  • Neuro-Coagulopathy: Blood Coagulation Factors in Central Nervous System Diseases.

    Publication Date: 12/10/2017 on International journal of molecular sciences
    by De Luca C, Virtuoso A, Maggio N, Papa M
    DOI: 10.3390/ijms18102128

    Blood coagulation factors and other proteins, with modulatory effects or modulated by the coagulation cascade have been reported to affect the pathophysiology of the central nervous system (CNS). The protease-activated receptors (PARs) pathway can be considered the central hub of this regulatory network, mainly through thrombin or activated protein C (aPC). These proteins, in fact, showed peculiar properties, being able to interfere with synaptic homeostasis other than coagulation itself. These specific functions modulate neuronal networks, acting both on resident (neurons, astrocytes, and microglia) as well as circulating immune system cells and the extracellular matrix. The pleiotropy of these effects is produced through different receptors, expressed in various cell types, in a dose- and time-dependent pattern. We reviewed how these pathways may be involved in neurodegenerative diseases (amyotrophic lateral sclerosis, Alzheimer's and Parkinson's diseases), multiple sclerosis, ischemic stroke and post-ischemic epilepsy, CNS cancer, addiction, and mental health. These data open up a new path for the potential therapeutic use of the agonist/antagonist of these proteins in the management of several central nervous system diseases.

  • Matrix Metalloproteinases, Neural Extracellular Matrix, and Central Nervous System Pathology.

    Publication Date: 01/01/2017 on Progress in molecular biology and translational science
    by De Luca C, Papa M
    DOI: 10.1016/bs.pmbts.2017.04.002

    The functionality and stability of the central nervous system (CNS) pabulum, called neural extracellular matrix (nECM), is paramount for the maintenance of a healthy network. The loosening or the damage of the scaffold disrupts synaptic transmission with the consequent imbalance of the neurotransmitters, reactive cells invasion, astrocytosis, new matrix deposition, digestion of the previous structure and ultimately, maladaptive plasticity with the loss of neuronal viability. nECM is constantly affected by CNS disorders, particularly in chronic modifying such as neurodegenerative disease, or in acute/subacute with chronic sequelae, like cerebrovascular and inflammatory pathology. Matrix metalloproteinases (MMPs) are the main interfering agent of nECM, guiding the balance of degradation and new deposition of proteins such as proteoglycans and glycoproteins, or glycosaminoglycans, such as hyaluronic acid. Activation of these enzymes is modulated by their physiologic inhibitors, the tissue inhibitors of MMPs or via other proteases inhibitors, as well as genetic or epigenetic up- or downregulation through molecular interaction or receptor activation. The appropriate understanding of the pathways underlying nECM modifications in CNS pathology is probably one of the pivotal future directions to identify the healthy brain network and subsequently design new therapies to interfere with the progression of the CNS disease and eventually find appropriate therapies.

  • Beyond peripheral nerve injury: spinal gliopathy and maladaptive synaptic plasticity.

    Publication Date: 01/09/2016 on Neural regeneration research
    by Cirillo G, Papa M
    DOI: 10.4103/1673-5374.191214
  • Looking Inside the Matrix: Perineuronal Nets in Plasticity, Maladaptive Plasticity and Neurological Disorders.

    Publication Date: 01/07/2016 on Neurochemical research
    by De Luca C, Papa M
    DOI: 10.1007/s11064-016-1876-2

    The integrity of the central nervous system (CNS) matrix is crucial for its proper function. Loss of the lattice-like structure compromise synaptic stability and can lead to the disruption of the excitatory/inhibitory balance, astrocytosis, maladaptive plasticity and neuronal death. Perineuronal nets (PNNs) in the extracellular matrix (ECM) provide synaptic integration and control the functional wiring between neurons. These nets are significantly modified during CNS disorders, such as neurodegenerative, cerebrovascular and inflammatory diseases. The breakdown or the modification of PNNs could be due to the activity of matrix metalloproteinases (MMPs) or to the deposition of proteoglycans, glycoproteins, and hyaluronic acid. The expression and the activity of ECM-degrading enzymes can be regulated with tissue inhibitors of MMPs or via transcriptional and epigenetic silencing or enhancement (i.e. via histone deacetylases). The identification of molecules and mechanisms able to modify these processes will be essential for a new perspective on brain functioning in health and disease, leading to a target-directed approach with drugs directly interfering with the molecular mechanism underlying neurological disorders.

  • The TGF-β pathway is activated by 5-fluorouracil treatment in drug resistant colorectal carcinoma cells.

    Publication Date: 19/04/2016 on Oncotarget
    by Romano G, Santi L, Bianco MR, Giuffrè MR, Pettinato M, Bugarin C, Garanzini C, Savarese L, Leoni S, Cerrito MG, Leone BE, Gaipa G, Grassilli E, Papa M, Lavitrano M, Giovannoni R
    DOI: 10.18632/oncotarget.7895

    TGF-β pathway is generally associated with the processes of metastasis, angiogenesis and EMT in cancer. Very little is known, however, about the role of TGF-β in cancer drug resistance. In this work, we show a specific activation of the TGF-β pathway in consequence of chemotherapeutic treatment in in vivo and in vitro models of colorectal carcinoma. 5-Fluorouracil (5FU) was able to stimulate the activation of SMAD3 and the transcription of specific genes such as ACVRL1, FN1 and TGFB1. On the other hand, the specific inhibition of TGF-βRI was able to repress the 5FU-induced genes transcription and to restore the sensitivity of chemoresistant cells to the toxic action of the drug, by decreasing the expression of BCL2L1 and ID1 genes. The role of the TGF-β molecule in the chemoresistant colon carcinoma cells' response to 5FU was further demonstrated by conditioned medium (CM) experiments: CM from 5FU-treated chemoresistant cells was able to protect chemosensitive cells against the toxic action of 5FU. In conclusion, these findings showed the pivotal role of TGF-β pathway in colon cancer mechanisms of drug resistance suggesting new possible approaches in diagnosis and treatment of colon cancer patients.

  • Modulation of Matrix Metalloproteinases Activity in the Ventral Horn of the Spinal Cord Re-stores Neuroglial Synaptic Homeostasis and Neurotrophic Support following Peripheral Nerve Injury.

    Publication Date: 30/03/2016 on PloS one
    by Cirillo G, Colangelo AM, De Luca C, Savarese L, Barillari MR, Alberghina L, Papa M
    DOI: 10.1371/journal.pone.0152750

    Modulation of extracellular matrix (ECM) remodeling after peripheral nerve injury (PNI) could represent a valid therapeutic strategy to prevent maladaptive synaptic plasticity in central nervous system (CNS). Inhibition of matrix metalloproteinases (MMPs) and maintaining a neurotrophic support could represent two approaches to prevent or reduce the maladaptive plastic changes in the ventral horn of spinal cord following PNI. The purpose of our study was to analyze changes in the ventral horn produced by gliopathy determined by the suffering of motor neurons following spared nerve injury (SNI) of the sciatic nerve and how the intrathecal (i.t.) administration of GM6001 (a MMPs inhibitor) or the NGF mimetic peptide BB14 modulate these events. Immunohistochemical analysis of spinal cord sections revealed that motor neuron disease following SNI was associated with increased microglial (Iba1) and astrocytic (GFAP) response in the ventral horn of the spinal cord, indicative of reactive gliosis. These changes were paralleled by decreased glial aminoacid transporters (glutamate GLT1 and glycine GlyT1), increased levels of the neuronal glutamate transporter EAAC1, and a net increase of the Glutamate/GABA ratio, as measured by HPLC analysis. These molecular changes correlated to a significant reduction of mature NGF levels in the ventral horn. Continuous i.t. infusion of both GM6001 and BB14 reduced reactive astrogliosis, recovered the expression of neuronal and glial transporters, lowering the Glutamate/GABA ratio. Inhibition of MMPs by GM6001 significantly increased mature NGF levels, but it was absolutely ineffective in modifying the reactivity of microglia cells. Therefore, MMPs inhibition, although supplies neurotrophic support to ECM components and restores neuro-glial transporters expression, differently modulates astrocytic and microglial response after PNI.

  • Comparing Alzheimer's and Parkinson's diseases networks using graph communities structure.

    Publication Date: 02/03/2016 on BMC systems biology
    by Calderone A, Formenti M, Aprea F, Papa M, Alberghina L, Colangelo AM, Bertolazzi P
    DOI: 10.1186/s12918-016-0270-7

    Recent advances in large datasets analysis offer new insights to modern biology allowing system-level investigation of pathologies. Here we describe a novel computational method that exploits the ever-growing amount of "omics" data to shed light on Alzheimer's and Parkinson's diseases. Neurological disorders exhibit a huge number of molecular alterations due to a complex interplay between genetic and environmental factors. Classical reductionist approaches are focused on a few elements, providing a narrow overview of the etiopathogenic complexity of multifactorial diseases. On the other hand, high-throughput technologies allow the evaluation of many components of biological systems and their behaviors. Analysis of Parkinson's Disease (PD) and Alzheimer's Disease (AD) from a network perspective can highlight proteins or pathways common but differently represented that can be discriminating between the two pathological conditions, thus highlight similarities and differences.

  • Astrocytes and Microglia-Mediated Immune Response in Maladaptive Plasticity is Differently Modulated by NGF in the Ventral Horn of the Spinal Cord Following Peripheral Nerve Injury.

    Publication Date: 01/01/2016 on Cellular and molecular neurobiology
    by De Luca C, Savarese L, Colangelo AM, Bianco MR, Cirillo G, Alberghina L, Papa M
    DOI: 10.1007/s10571-015-0218-2

    Reactive astrocytes and activated microglia are the key players in several pathophysiologic modifications of the central nervous system. We used the spared nerve injury (SNI) of the sciatic nerve to induce glial maladaptive response in the ventral horn of lumbar spinal cord and examine its role in the remodeling of the tripartite synapse plasticity. Imaging the ventral horn revealed that SNI was associated with both an early microglial and astrocytic activation, assessed, respectively, by analysis of Iba1 and GFAP expression. Microglia, in particular, localized peculiarly surrounding the motor neurons somata. Perineuronal astrocytes, which play a key role in maintaining the homeostasis of neuronal circuitry, underwent a substantial phenotypic change following peripheral axotomy, producing reactive gliosis. The gliosis was associated with the reduction of glial aminoacid transporters (GLT1 and GlyT1) and increase of neuronal glutamate transporter EAAC1. Although the expression of GABAergic neuronal marker GAD65/67 showed no change, glutamate increase, as demonstrated by HPLC analysis, shifted the excitatory/inhibitory balance as showed by the net increase of the glutamate/GABA ratio. Moreover, endogenous NGF levels were altered in SNI animals and not restored by the intrathecal NGF administration. This treatment reverted phenotypic changes associated with reactive astrocytosis, but failed to modify microglia activation. These findings on one hand confirm the correlation between gliopathy and maladaptive plasticity of the spinal synaptic circuitry, on the other hand add new data concerning the complex peculiar behavior of different glial cells in neuronal degenerative processes, defining a special role of microglia in sustaining the inflammatory response.

  • Purinergic Modulation of Spinal Neuroglial Maladaptive Plasticity Following Peripheral Nerve Injury.

    Publication Date: 01/12/2015 on Molecular neurobiology
    by Cirillo G, Colangelo AM, Berbenni M, Ippolito VM, De Luca C, Verdesca F, Savarese L, Alberghina L, Maggio N, Papa M
    DOI: 10.1007/s12035-014-8943-y

    Modulation of spinal reactive gliosis following peripheral nerve injury (PNI) is a promising strategy to restore synaptic homeostasis. Oxidized ATP (OxATP), a nonselective antagonist of purinergic P2X receptors, was found to recover a neuropathic behavior following PNI. We investigated the role of intraperitoneal (i.p.) OxATP treatment in restoring the expression of neuronal and glial markers in the mouse spinal cord after sciatic spared nerve injury (SNI). Using in vivo two-photon microscopy, we imaged Ca(2+) transients in neurons and astrocytes of the dorsal horn of spinal cord at rest and upon right hind paw electrical stimulation in sham, SNI, and OxATP-treated mice. Neuropathic behavior was investigated by von Frey and thermal plantar test. Glial [glial fibrillary acidic protein (GFAP), ionized calcium-binding adaptor molecule 1 (Iba1)] and GABAergic [vesicular GABA transporter (vGAT) and glutamic acid decarboxylase 65/76 (GAD65/67)] markers and glial [glutamate transporter (GLT1) and GLAST] and neuronal amino acid [EAAC1, vesicular glutamate transporter 1 (vGLUT1)] transporters have been evaluated. In SNI mice, we found (i) increased glial response, (ii) decreased glial amino acid transporters, and (iii) increased levels of neuronal amino acid transporters, and (iv) in vivo analysis of spinal neurons and astrocytes showed a persistent increase of Ca(2+) levels. OxATP administration reduced glial activation, modulated the expression of glial and neuronal glutamate/GABA transporters, restored neuronal and astrocytic Ca(2+) levels, and prevented neuropathic behavior. In vitro studies validated that OxATP (i) reduced levels of reactive oxygen species (ROS), (ii) reduced astrocytic proliferation, (iii) increase vGLUT expression. All together, these data support the correlation between reactive gliosis and perturbation of the spinal synaptic homeostasis and the role played by the purinergic system in modulating spinal plasticity following PNI.