Altered properties of amyloidogenic prion protein in genetic Creutzfeldt-Jakob disease with PRNP V180I mutation in response to pentosan polysulfate.

Genetic Creutzfeldt-Jakob disease (gCJD) with V180I prion protein gene (PRNP) mutation shows weaker prion protein (PrP) deposition histologically compared with sporadic CJD, and it is more difficult to detect protease-resistant prion protein in immunoblotting. However, we previously reported the autopsy case of a patient with V180I gCJD who was treated with pentosan polysulfate sodium (PPS); this case had increased protease-resistant PrP deposition. It has been suggested that PPS might reduce protease-resistant PrP; however, the detailed pharmacological and histopathological effects of PPS in humans remain unknown. We examined autopsied human brain tissue from four cases with V180I gCJD that were added to our archives between 2011 and 2021: two cases treated with PPS and two cases without PPS. We conducted a neuropathological assessment, including immunohistochemistry for PrP. We also performed immunoblotting for PrP on homogenate samples from each brain to detect protease-resistant PrP using both a conventional procedure and size-exclusion gel chromatography for the purification of oligomeric PrP. Both PPS-treated cases showed long survival time over 5 years from onset and increased PrP deposition with a characteristic pattern of coarse granular depositions and congophilic PrP microspheres, whereas the cases without PPS showed around 1-year survival from onset and relatively mild neuronal loss and synaptic PrP deposition. Although cortical gliosis seemed similar among all cases, aquaporin 4-expression as a hallmark of astrocytic function was increased predominantly in PPS cases. Immunoblotting of non-PPS cases revealed protease-resistant PrP in the oligomeric fraction only, whereas the PPS-treated cases showed clear signals using conventional procedures and in the oligomeric fraction. These unique biochemical and histopathological changes may reflect the progression of V180I gCJD and its modification by PPS, suggesting the possible existence of toxic PrP-oligomer in the pathophysiology of V180I gCJD and beneficial effects of PPS toward the aggregation and detoxication of toxic PrP-oligomer.

Heidenhain Variant of Sporadic Creutzfeldt-Jakob Disease with a Variety of Visual Symptoms: A Case Report with Autopsy Study.

BACKGROUND Sporadic Creutzfeldt-Jakob disease (sCJD) is a fatal disease caused by the change of prion protein (PrP). Affected patients present with rapidly progressive cognitive dysfunction, myoclonus, or akinetic mutism. Diagnosing the Heidenhain variant of sCJD, which initially causes various visual symptoms, can be particularly difficult. CASE REPORT A 72-year-old woman presented with a 2- to 3-month history of photophobia, blurring vision in both eyes. Seven days previously, she showed visual impairment of 20/2000 in both eyes. Left homonymous hemianopia and restricted downward movement of the left eye were observed with an intact pupillary light reflex and normal fundoscopy. On admission, her visual acuity was light perception. Cranial magnetic resonance imaging revealed no abnormality, and electroencephalography showed no periodic synchronous discharges. Cerebrospinal fluid examination on the sixth hospital day revealed tau and 14-3-3 protein with a positive result of real-time quaking-induced conversion. She thereafter developed myoclonus and akinetic mutism and died. Autopsy revealed thinning and spongiform change of the cerebral cortex of the right occipital lobe. Immunostaining showed synaptic-type deposits of abnormal PrP and hypertrophic astrocytes. Consequently, she was diagnosed with the Heidenhain variant of sCJD with both methionine/methionine type 1 and type 2 cortical form based on the western blot of cerebral tissue and PrP gene codon 129 polymorphism. CONCLUSIONS When a patient presents with various progressive visual symptoms, even without typical findings of electroencephalography or cranial magnetic resonance imaging, it is essential to suspect the Heidenhain variant of sCJD and perform appropriate cerebrospinal fluid tests.

Mutated FUS in familial amyotrophic lateral sclerosis involves multiple hnRNPs in the formation of neuronal cytoplasmic inclusions.

Fused in sarcoma (FUS), coded by FUS, is a heterogeneous nuclear ribonucleoprotein (hnRNP). FUS mutations are among the major mutations in familial amyotrophic lateral sclerosis (ALS-FUS: ALS6). The pathological hallmarks of ALS-FUS are FUS-positive neuronal cytoplasmic inclusions (NCI). We examined various hnRNPs in FUS NCIs in the hippocampus in ALS-FUS cases with different FUS mutations (Case 1, H517P; Case 2, R521C). We also examined TDP43-positive NCIs in sporadic ALS hippocampi. Immunohistochemistry was performed using primary antibodies against FUS, p-TDP43, TDP43, hnRNPA1, hnRNPD, PCBP1, PCBP2, and p62. Numerous FUS inclusions were found in the hippocampal granule and pyramidal cell layers. Double immunofluorescence revealed colocalization of FUS and p-TDP43, and FUS and PCBP2 (p-TDP43/FUS: 64.3%, PCBP2/FUS: 23.9%). Colocalization of FUS and PCBP1, however, was rare (PCBP1/FUS: 7.6%). In the hippocampi of patients with sporadic ALS, no colocalization was observed between TDP43-positive inclusions and other hnRNPs. This is the first study to show that FUS inclusions colocalize with other hnRNPs, such as TDP43, PCBP2, and PCBP1. These findings suggest that in ALS-FUS, FUS inclusions are the initiators, followed by alterations of multiple other hnRNPs, resulting in impaired RNA metabolism.

Characteristic distribution and molecular properties of normal cellular prion protein in human endocrine and exocrine tissues.

Prion disease is an infectious and fatal neurodegenerative disease. Human prion disease autopsy studies have revealed abnormal prion protein (PrPSc) deposits in the central nervous system and systemic organs. In deer, chronic wasting disease has also become a global problem, with PrPSc in saliva and feces. Therefore, understanding normal cellular prion proteins (PrPc) characteristics in human systemic organs is important since they could be a PrPSc source. This study used western blotting and immunohistochemistry to investigate endocrine and exocrine tissues, such as the human pituitary, adrenal, submandibular glands and the pancreas. All tissues had 30-40 kDa PrP signals, which is a slightly higher molecular weight than normal brain tissue. Most cytoplasmic PrP-positive adenohypophyseal cells were immunopositive for nuclear pituitary-specific positive transcription factor 1. The adrenal medulla and islet cells of the pancreas were PrP-positive and colocalized with chromogranin A. The duct epithelium in the submandibular gland and pancreas were immunopositive for PrP. This study reports the characteristic molecular properties and detailed tissue localization of PrPc in endocrine and exocrine tissues, which is important for infection control and diagnosis.

Cerebral Tuberculoma with Mild Posterior Cervical Pain as the Main Symptom Despite Extensive Brain Lesions.

A 59-year-old woman with a diabetes history experienced mild neck pain. A neurological examination revealed only mild neck stiffness. Magnetic resonance imaging showed extensive T2-weighted high-intensity lesions with patchy gadolinium enhancement mainly involving the white matter in the right parietal lobe. A cerebrospinal fluid analysis revealed increased protein levels and pleocytosis. While QuantiFERON-TB Gold was positive, computed tomography (CT) and fluorodeoxyglucose on positron emission tomography-CT of the whole body showed no abnormal accumulation, suggesting tuberculosis. A brain biopsy revealed cerebral tuberculoma. As cerebral tuberculoma can show minimal neurological symptoms despite extensive lesions, a cautious examination and early treatment are required to prevent a devastating prognosis.

PCBP2 Is Downregulated in Degenerating Neurons and Rarely Observed in TDP-43-Positive Inclusions in Sporadic Amyotrophic Lateral Sclerosis.

Various heterogeneous nuclear ribonucleoproteins (hnRNPs) are deposited in pathological inclusions of amyotrophic lateral sclerosis (ALS) and related diseases, such as frontotemporal lobar degeneration (FTLD). Recently, poly (rC)-binding protein 2 (PCBP2, hnRNP-E2), a member of the hnRNP family, was reported to be colocalized with transactivation-responsive DNA-binding protein 43 kDa (TDP-43)-immunopositive inclusions in cases of FTLD-TDP. Here, we used immunohistochemical methods to investigate PCBP1 and PCBP2 expression in the spinal cords of sporadic ALS patients, with special reference to TDP-43-positive inclusions. Thirty autopsy cases of sporadic ALS were examined by immunohistochemistry using antibodies against PCBP1, PCBP2, sequestosome 1 (p62), and TDP-43. In control subjects without neurological disorders, neurons predominantly expressed PCBP2, rather than PCBP1, in their cytoplasm and nuclei. Anterior horn cells of sporadic ALS patients often had various levels of PCBP2 expression, and motor neurons with skein-like inclusions often had reduced or lost cytoplasmic and nuclear PCBP2 staining. Notably, one case with FTLD-TDP subtype B pathology had marked colocalization of TDP-43 and PCBP2 in the cytoplasmic inclusions and dystrophic neurites of the cerebral cortex, hippocampus, and spinal cord. In conclusion, PCBP2 was reduced in anterior horn cells of sporadic ALS, but its occurrence in TDP-43 inclusions was a rare phenomenon.

Expanded polyglutamine impairs normal nuclear distribution of fused in sarcoma and poly (rC)-binding protein 1 in Huntington's disease.

Huntington's disease (HD) is an inherited neurodegenerative disease caused by a polyglutamine repeat expansion in the huntingtin protein. Immunohistochemical studies using the 1C2 antibody for polyglutamine expansion have detected characteristic intranuclear inclusions (INIs) in affected neurons in HD. Further, in vitro and mouse models of HD have shown that the INIs recruit several proteins relating to RNA splicing and translation. In the present study, we immunohistochemically investigated the association of INIs with various heterogeneous nuclear ribonucleoproteins in the cerebral cortex of four autopsy cases of HD. Fused in sarcoma (FUS) was colocalized with 1C2-positive nuclear inclusions in all examined cases. Localization of poly (rC)-binding protein 1 (PCBP1) in 1C2-positive nuclear inclusions was also observed. Double immunofluorescence revealed complete or partial loss of the normal, diffuse nuclear distribution of FUS or PCBP1 in neurons with 1C2-positive nuclear inclusions. This maldistribution of FUS in cortical neurons suggests a severe disturbance of messenger RNA processing, which may be a common pathogenetic mechanism of FUS-related familial amyotrophic lateral sclerosis.