Activation of the nuclear factor κB/c-Rel can increase neuronal resilience to pathological noxae by regulating the expression of pro-survival manganese superoxide dismutase (MnSOD, now known as SOD2) and Bcl-xL genes. We show here that c-Rel-deficient (c-rel−/−) mice developed a Parkinson’s disease-like neuropathology with ageing. At 18 months of age, c-rel−/− mice exhibited a significant loss of dopaminergic neurons in the substantia nigra pars compacta, as assessed by tyrosine hydroxylase-immunoreactivity and Nissl staining. Nigral degeneration was accompanied by a significant loss of dopaminergic terminals and a significant reduction of dopamine and homovanillic acid levels in the striatum. Mice deficient of the c-Rel factor exhibited a marked immunoreactivity for fibrillary α-synuclein in the substantia nigra pars compacta as well as increased expression of divalent metal transporter 1 (DMT1) and iron staining in both the substantia nigra pars compacta and striatum. Aged c-rel−/− mouse brain were characterized by increased microglial reactivity in the basal ganglia, but no astrocytic reaction. In addition, c-rel−/− mice showed age-dependent deficits in locomotor and total activity and various gait-related deficits during a catwalk analysis that were reminiscent of bradykinesia and muscle rigidity. Both locomotor and gait-related deficits recovered in c-rel−/− mice treated with l-3,4-dihydroxyphenylalanine. These data suggest that c-Rel may act as a regulator of the substantia nigra pars compacta resilience to ageing and that aged c-rel−/− mice may be a suitable model of Parkinson’s disease.

NF-κB factors are cardinal transcriptional regulators of inflammation and apoptosis, involved in the brain programing of systemic aging and in brain damage. The composition of NF-κB active dimers and epigenetic mechanisms modulating histone acetylation, finely condition neuronal resilience to brain insults. In stroke models, the activation of NF-κB/c-Rel promotes neuroprotective effects by transcription of specific anti-apoptotic genes. Conversely, aberrant activation of NF-κB/RelA showing reduced level of total acetylation, but site-specific acetylation on lysine 310, triggers the expression of pro-apoptotic genes. Constitutive knockout of c-Rel shatters the resilience of substantia nigra (SN) dopaminergic (DA) neurons to aging and induces a parkinsonian like pathology in mice. c-rel−/− mice show increased level of aberrantly acetylated RelA in the basal ganglia, neuroinflammation, accumulation of alpha-synuclein, and iron. Moreover, they develop motor deficits responsive to l-DOPA treatment and associated with loss of DA neurons in the SN. Here, we discuss the effect of unbalanced activation of RelA and c-Rel during aging and propose novel challenges for the development of therapeutic strategies in neurodegenerative diseases.

Parkinson's disease (Pd) is an important disabling age-related disorder and is the second most common neurodegenerative disease. currently, no established molecular biomarkers exist for the early diagnosis of Pd. circulating microRNAs (miRNAs), either vesicle-free or encapsulated in extracellular vesicles (EVs), have emerged as potential blood-based biomarkers also for neurodegenerative diseases. In this exploratory study, we focused on miR-34a-5p because of its well-documented involvement in neurobiology. To explore a differential profile of circulating miR-34a-5p in PD, Pd patients and age-matched control subjects were enrolled. Serial ultracentrifugation steps and density gradient were used to separate EV subpopulations from plasma according to their different sedimentation properties (Large, Medium, Small EVs). characterization of EV types was performed using western blotting and atomic force microscopy (AFM); purity from protein contaminants was checked with the colorimetric nanoplasmonic assay. circulating miR-34a-5p levels were evaluated using qPcR in plasma and in each EV type. miR-34a-5p was significantly up-regulated in small EVs devoid of exogenous protein contaminants (pure SEVs) from Pd patients and ROc analysis indicated a good diagnostic performance in discriminating patients from controls (AUc=0.74, P<0.05). Moreover, miR-34a-5p levels in pure SEVs were associated with disease duration, Hoehn and Yahr and Beck depression Inventory scores. These results underline the necessity to examine the miRNA content of each EV subpopulation to identify miRNA candidates with potential diagnostic value and lay the basis for future studies to validate the overexpression of circulating miR-34a-5p in Pd via the use of pure SEVs.

The loss of dopaminergic neurons of the nigrostriatal system underlies the onset of the typical motor symptoms of Parkinson's disease (PD). Lewy bodies (LB) and Lewy neurites (LN), proteinaceous inclusions mainly composed of insoluble α-synuclein (α-syn) fibrils are key neuropathological hallmarks of the brain of affected patients. Compelling evidence supports that in the early prodromal phases of PD, synaptic terminal and axonal alterations initiate and drive a retrograde degeneration process culminating with the loss of nigral dopaminergic neurons. This notwithstanding, the molecular triggers remain to be fully elucidated. Although it has been shown that α-syn fibrillary aggregation can induce early synaptic and axonal impairment and cause nigrostriatal degeneration, we still ignore how and why α-syn fibrillation begins. Nuclear factor-κB (NF-κB) transcription factors, key regulators of inflammation and apoptosis, are involved in the brain programming of systemic aging as well as in the pathogenesis of several neurodegenerative diseases. The NF-κB family of factors consists of five different subunits (c-Rel, p65/RelA, p50, RelB, and p52), which combine to form transcriptionally active dimers. Different findings point out a role of RelA in PD. Interestingly, the nuclear content of RelA is abnormally increased in nigral dopamine (DA) neurons and glial cells of PD patients. Inhibition of RelA exert neuroprotection against (1-methyl-4-phenyl-1,2,3,6tetrahydropyridine) MPTP and 1-methyl-4-phenylpyridinium (MPP+) toxicity, suggesting that this factor decreases neuronal resilience. Conversely, the c-Rel subunit can exert neuroprotective actions. We recently described that mice deficient for c-Rel develop a PD-like motor and non-motor phenotype characterized by progressive brain α-syn accumulation and early synaptic changes preceding the frank loss of nigrostriatal neurons. This evidence supports that dysregulations in this transcription factors may be involved in the onset of PD. This review highlights observations supporting a possible interplay between NF-κB dysregulation and α-syn pathology in PD, with the aim to disclose novel potential mechanisms involved in the pathogenesis of this disorder.

Mast cells (MCs) are densely granulated perivascular resident cells of hematopoietic origin. Through the release of preformed mediators stored in their granules and newly synthesized molecules, they are able to initiate, modulate, and prolong the immune response upon activation. Their presence in the central nervous system (CNS) has been documented for more than a century. Over the years, MCs have been associated with various neuroinflammatory conditions of CNS, including stroke. They can exacerbate CNS damage in models of ischemic and hemorrhagic stroke by amplifying the inflammatory responses and promoting brain–blood barrier disruption, brain edema, extravasation, and hemorrhage. Here, we review the role of these peculiar cells in the pathophysiology of stroke, in both immature and adult brain. Further, we discuss the role of MCs as potential targets for the treatment of stroke and the compounds potentially active as MCs modulators.