Pediococcus acidilactici reduces tau pathology and ameliorates behavioral deficits in models of neurodegenerative disorders

BACKGROUND

Alzheimer's disease (AD), affecting many elders worldwide, is characterized by A-beta and tau-related cognitive decline. Accumulating evidence suggests that brain iron accumulation is an important characteristic of AD. However, the function and mechanism of the iron-mediated gut-brain axis on AD is still unclear.

METHODS

A Caenorhabditis elegans model with tau-overexpression and a high-Fe diet mouse model of cognitive impairment was used for probiotic function evaluation. With the use of qPCR, and immunoblotting, the probiotic regulated differential expression of AD markers and iron related transporting genes was determined. Colorimetric kits, IHC staining, and immunofluorescence have been performed to explore the probiotic mechanism on the development of gut-brain links and brain iron accumulation.

RESULTS

In the present study, a high-Fe diet mouse model was used for evaluation in which cognitive impairment, higher A-beta, tau and phosphorylated (p)-tau expression, and dysfunctional phosphate distribution were observed. Considering the close crosstalk between intestine and brain, probiotics were then employed to delay the process of cognitive impairment in the HFe mouse model. Pediococcus acidilactici (PA), but not Bacillus subtilis (BN) administration in HFe-fed mice reduced brain iron accumulation, enhanced global alkaline phosphatase (AP) activity, accelerated dephosphorylation, lowered phosphate levels and increased brain urate production. In addition, because PA regulated cognitive behavior in HFe fed mice, we used the transgenic Caenorhabditis elegans with over-expressed human p-tau for model, and then PA fed worms became more active and longer lived than E.coli fed worms, as well as p-tau was down-regulated. These results suggest that brain iron accumulation influences AD risk proteins and various metabolites. Furthermore, PA was shown to reverse tau-induced pathogenesis via iron transporters and AP-urate interaction.

CONCLUSIONS

PA administration studies demonstrate that PA is an important mediator of tau protein reduction, p-tau expression and neurodegenerative behavior both in Caenorhabditis elegans and iron-overload mice. Finally, our results provide candidates for AP modulation strategies as preventive tools for promoting brain health. Video Abstract.

Type 1 neurodegeneration with brain iron accumulation: a case report

BACKGROUND

Type 1 neurodegeneration with brain iron accumulation is a rare neurological disorder with estimated prevalence of one to two per million persons worldwide, characterized by progressive degeneration of basal ganglia, globus pallidus, and reticular part of substantia nigra, produced by brain iron accumulation due to a defect in the gene producing pantothenate kinase 2. Clinical presentations include dystonia, dysarthria, dysphagia, dementia, severe mental retardation, and severe movement disability at later stages. The characteristic pattern on brain magnetic resonance imaging shows the "eye of the tiger" sign. Treatment in late stages is mainly symptomatic. We report the case of a Cuban boy with high-severity brain iron accumulation, with positive clinical and imaging findings diagnosed in a late stage of the illness. This degree of severity has never been reported in Cuba and is rarely reported worldwide.

CASE PRESENTATION

We present the case of a 19-year-old male white Cuban boy who presented to our department with features of spasticity, dystonia, gait difficulty, dysarthria, dysphagia, aggressiveness, and sleep disorders. He was diagnosed with pantothenate kinase-associated neurodegeneration on the basis of clinical findings and typical "eye of the tiger" pattern on brain magnetic resonance imaging. Detailed evaluation was carried out, and symptomatic treatment and physiotherapy were started with trihexyphenidyl, cabergoline, baclofen, and intramuscular botulinum neurotoxin as well as daily home sessions of passive stretching, weight bearing, and muscle massaging. At 3 months reevaluation, the patient showed a great improvement of motor function, with a decrease of dystonic symptoms, although language, cognition, and functional independence showed no improvement. The prognosis of the patient remains reserved.

CONCLUSION

The diagnosis can be made based on the presence of clinical and imaging features. The presence of "eye-of-the-tiger" sign on magnetic resonance imaging must be considered a nearly pathognomonic sign of neurodegeneration with brain iron accumulation presence. Treatment after high-severity presentation remains directed toward symptomatic findings. Both dopamine agonists and anticholinergic agents are useful to treat motor symptoms, but there is not yet an effective treatment to stop the underlying degeneration. New therapeutic approaches are needed to counteract late stages of the disease and improve prognosis.

Early-Onset Parkinson's Disease and Brain Iron Accumulation Caused by a Novel Homozygous DJ-1 Mutation

DJ-1 mutations are rare causes of autosomal recessive early-onset Parkinson's disease (AR-EOPD) and relatively rarely reported in the Chinese population. Here, we used the whole-exome sequencing and Sanger sequencing to investigate DJ-1 mutations in the Chinese population and confirmed the pathogenicity of the mutation using primary fibroblasts established from skin biopsies. We identified a novel homozygous mutation (c.390delA, p.D131Tfs*3) in DJ-1 in a consanguineous Chinese family. The proband in this family had parkinsonism at the age of 22. His brain MRI indicated brain iron accumulation in the basal ganglia and cerebellum. The novel mutation caused DJ-1 protein deficiency, led to mitochondrial dysfunction, inhibited cell proliferation, and anti-oxidant defense.

"Eye of tiger sign" mimic in an adolescent boy with mitochondrial membrane protein associated neurodegeneration (MPAN)

Neurodegeneration with brain iron accumulation (NBIA) refers to an inherited heterogeneous group of disorders pathologically characterized by focal brain iron deposition. Clinical phenotype, imaging findings and genotype are variable among the different types of this disorder. In this case report, we describe the imaging finding of an adolescent boy with mitochondrial membrane protein associated neurodegeneration (MPAN), a subentity of NBIA. Magnetic resonance imaging of brain revealed hypointensity of globi pallidi with medial medullary lamina appearing as a hyperintense streak in T2 weighted images. Mild cerebellar atrophy in T2 weighted images and blooming of substantia nigra and globi pallidi in susceptibility weighted images were also observed. Imaging findings in patients with MPAN mimics the eye of tiger appearance in patients with pantothenate kinase associated neurodegeneration. Classical phenotype and eye of tiger sign mimic in imaging of patients with NBIA should raise the suspect for MPAN. Genetic studies helps in the confirmation of diagnosis of this neurodegenerative disorder.

The neurologic aspects of hypomelanosis of Ito: Case report and review of the literature

The term hypomelanosis of Ito (HI) is applied to individuals with skin hypopigmentation along the lines of Blaschko. Although it was originally described as a purely cutaneous disease, subsequent studies describing HI reported a 33% to 94% association with multiple extracutaneous manifestations, mostly of the central nervous and musculoskeletal systems. This leads to characterization of HI as a neurocutaneous disorder. We report a 10-year-old boy who presented with constellation of multiple congenital anomalies including facial dysmorphism, skin hypopigmentation, musculoskeletal, and nervous system abnormalities. The latter manifested as hypotonia, generalized seizures, and mild mental retardation. Cranial magnetic resonance imaging revealed normal finding initially, however; follow-up diffusion weighted images were suggestive of a possible iron accumulation. The facial phenotype coupled with the bilateral globus pallidi lesions were never been reported in association with HI. Thus, our patient represents a possible novel example of HI.