Intracellular Inclusion Bodies Research Articles

Manipulating Microbial Cell Morphology for the Sustainable Production of Biopolymers.

The total rate of plastic production is anticipated to surpass 1.1 billion tons per year by 2050. Plastic waste is non-biodegradable and accumulates in natural ecosystems. In 2020, the total amount of plastic waste was estimated to be 367 million metric tons, leading to unmanageable waste disposal and environmental pollution issues. Plastics are produced from petroleum and natural gases. Given the limited fossil fuel reserves and the need to circumvent pollution problems, the focus has shifted to biodegradable biopolymers, such as polyhydroxyalkanoates (PHAs), polylactic acid, and polycaprolactone. PHAs are gaining importance because diverse bacteria can produce them as intracellular inclusion bodies using biowastes as feed. A critical component in PHA production is the downstream processing procedures of recovery and purification. In this review, different bioengineering approaches targeted at modifying the cell morphology and synchronizing cell lysis with the biosynthetic cycle are presented for product separation and extraction. Complementing genetic engineering strategies with conventional downstream processes, these approaches are expected to produce PHA sustainably.

First Report of Viral Nervous Necrosis in Asian Sea Bass, Lates Calcarifer Cultured in Sri Lanka

Viral Nervous Necrosis (VNN) caused by Betanodavirus is a devastating disease in aquatic animals. The virus infects both marine and freshwater fish worldwide. Vacuolating necrosis of neural cells of the brain, the retina of the eye, and the spinal cord of the infected fish are the primary histological lesions of the condition. It causes up to 100% mortality in larvae and juvenile fish and can cause significant death in adult fish. The present study detected viral nervous necrosis in larvae and fry of Asian sea bass (Lates calcarifer) with progressive mortality of up to 95% in one week during the Northeast monsoon when the mean water temperature was 27 to 29°C. Histopathological examination of the moribund fish revealed extensive vacuolation and gliosis in the olfactory bulb, the optic lobe of the forebrain, and the inner and outer layer of the retina. Furthermore, tissues of the brain and the retina had intracellular inclusion bodies suggesting viral etiology, further justified by the negative results of the bacterial and parasitic examinations. The Reverse Transcriptase Polymerase Chain Reaction (RT-PCR) test additionally confirms the etiology diagnosis using specific primers designed previously. The histopathology and RT-PCR results suggest that the mortalities of Asian sea bass were due to the VNN. The present finding is the first report of the VNN associated with mass mortalities in Asian seabass cultured in Sri Lanka. These crucial findings emphasize the need for quarantine and control strategies to prevent the spread of the virus and outbreak of the disease.

Exploiting the aggregation propensity of beta-lactamases to design inhibitors that induce enzyme misfolding

There is an arms race between beta-lactam antibiotics development and co-evolving beta-lactamases, which provide resistance by breaking down beta-lactam rings. We have observed that certain beta-lactamases tend to aggregate, which persists throughout their evolution under the selective pressure of antibiotics on their active sites. Interestingly, we find that existing beta-lactamase active site inhibitors can act as molecular chaperones, promoting the proper folding of these resistance factors. Therefore, we have created Pept-Ins, synthetic peptides designed to exploit the structural weaknesses of beta-lactamases by causing them to misfold into intracellular inclusion bodies. This approach restores sensitivity to a wide range of beta-lactam antibiotics in resistant clinical isolates, including those with Extended Spectrum variants that pose significant challenges in medical practice. Our findings suggest that targeted aggregation of resistance factors could offer a strategy for identifying molecules that aid in addressing the global antibiotic resistance crisis.

First Molecular Detection and Phylogenetic Analysis of Ehrlichia canis in Dogs from Baghdad, Iraq.

Ehrlichia canis is a pathogen considered a disease in both dogs and breeders, a tropical and non-tropical disease caused by an intracellular pathogen. For the first time, the study aimed at hematological and molecular detection and phylogenetic analysis of Erlchcia canis in dogs in Baghdad, Iraq. Two hundred dogs were clinically examined from April to September 2019 at the Veterinary Hospital in Baghdad. Blood samples with EDTA tubes were used for microscopic examination, complete blood count (CBC) and polymerase chain reaction (PCR). The study's results revealed that the infection rate was 3.5% when analyzed using microscopic or molecular methods. Ataxia, posterior recumbency, and occasionally vision problems were identified as the clinical characteristics that were distinguished in this study. The hematological values showed no significant differences between infected and uninfected dogs (P>0.05). However, the study did show that infected dogs had neutrophilia and monocytosis. Four samples were sent to the sequencers, and NCBI accession numbers were assigned to two isolates of the Ehrlichia canis 16s rRNA gene (MN227483.1 and MN227484.1). This study showed that 99% of the isolates matched those found in other countries. The study concluded that microscopic examination is not the best method for diagnosing Ehrlichia in dogs because it requires the ability to differentiate microscopically between intracellular inclusion bodies and the included morula of Ehrlichia and may produce incorrect results. Instead, molecular tests are used to confirm an Ehrlichia diagnosis.

Bivalent metal ions induce formation of α-synuclein fibril polymorphs with different cytotoxicities

α-Synuclein (α-Syn) aggregates are key components of intracellular inclusion bodies characteristic of Parkinson’s disease (PD) and other synucleinopathies. Metal ions have been considered as the important etiological factors in PD since their interactions with α-Syn alter the kinetics of fibrillation. In the present study, we have systematically explored the effects of Zn2+, Cu2+, Ca2+, and Mg2+ cations on α-Syn fibril formation. Specifically, we determined fibrillation kinetics, size, morphology, and secondary structure of the fibrils and their cytotoxic activity. While all cations accelerate fibrillation, we observed distinct effects of the different ions. For example, Zn2+ induced fibrillation by lower tlag and higher kapp and formation of shorter fibrils, while Ca2+ ions lead to formation of longer fibrils, as evidenced by dynamic light scattering and atomic force microscopy studies. Additionally, the morphology of formed fibrils was different. Circular dichroism and attenuated total reflection-Fourier transform infrared spectroscopies revealed higher contents of β-sheets in fibrils. Interestingly, cell viability studies indicated nontoxicity of α-Syn fibrils formed in the presence of Zn2+ ions, while the fibrils formed in the presence of Cu2+, Ca2+, and Mg2+ were cytotoxic. Our results revealed that α-Syn fibrils formed in the presence of different divalent cations have distinct structural and cytotoxic features.

ANTAGONISM OF Bacillus licheniformis M2–7 AGAINST PHYTOPATHOGEN FUNGI OF Mangifera indica L.

The biological control using organisms that inhibit growth or the appearance of pests or diseases has proven to be a successful alternative for mango disease control. In this work, in vitro analyses were carried out with Bacillus licheniformis M2–7 and B. licheniformis LYA12 strain derived from M2–7 against the phytopathogenic fungi Aspergillus oryzae, Colletotrichum sp., and Aspergillus niger. Besides, the effect of bacteria on the micellar structure of phytopathogenic fungi was observed and evaluated through real-time PCR, the expression of two main metacaspases (casA and casB) that triggers the process of programmed cell death in fungi. The results obtained showed that both bacterial species inhibited by 45, 40, and 35 % the fungal growth of Aspergillus oryzae , Colletotrichum sp., and Aspergillus niger, respectively. The bacteria presence affected the mycelial appearance of the fungi because they presented fragmentation of the hyphae with intracellular inclusion bodies, swellings, malformations and scarce growth of the hyphae. The gene expression results conclude that the LYA12 and M2-7 strains against A. oryzae and A. niger have a fungicidal effect; therefore, the bacterial strains could be used in disease control in mango.

Spatial Distribution of Intracellular Ion Concentrations in Aggregate‐Forming HeLa Cells Analyzed by μ‐XRF Imaging

Protein aggregation is a hallmark of several severe neurodegenerative disorders such as Huntington's, Parkinson's, or Alzheimer's disease. Metal ions play a profound role in protein aggregation and altered metal‐ion homeostasis is associated with disease progression. Here we utilize μ‐X‐ray fluorescence imaging in combination with rapid freezing to resolve the elemental distribution of phosphorus, sulfur, potassium, and zinc in huntingtin exon‐1‐mYFP expressing HeLa cells. Using quantitative XRF analysis, we find a threefold increase in zinc and a 10‐fold enrichment of potassium that can be attributed to cellular stress response. While the averaged intracellular ion areal masses are significantly different in aggregate‐containing cells, a local intracellular analysis shows no different ion content at the location of intracellular inclusion bodies. The results are compared to corresponding experiments on HeLa cells forming pseudoisocyanine chloride aggregates. As those show similar results, changes in ion concentrations are not exclusively linked to huntingtin exon‐1 amyloid formation.

Neurons with Cat's Eyes: A Synthetic Strain of α-Synuclein Fibrils Seeding Neuronal Intranuclear Inclusions.

The distinct neuropathological features of the different α-Synucleinopathies, as well as the diversity of the α-Synuclein (α-Syn) intracellular inclusion bodies observed in post mortem brain sections, are thought to reflect the strain diversity characterizing invasive α-Syn amyloids. However, this “one strain, one disease” view is still hypothetical, and to date, a possible disease-specific contribution of non-amyloid factors has not been ruled out. In Multiple System Atrophy (MSA), the buildup of α-Syn inclusions in oligodendrocytes seems to result from the terminal storage of α-Syn amyloid aggregates first pre-assembled in neurons. This assembly occurs at the level of neuronal cytoplasmic inclusions, and even earlier, within neuronal intranuclear inclusions (NIIs). Intriguingly, α-Syn NIIs are never observed in α-Synucleinopathies other than MSA, suggesting that these inclusions originate (i) from the unique molecular properties of the α-Syn fibril strains encountered in this disease, or alternatively, (ii) from other factors specifically dysregulated in MSA and driving the intranuclear fibrillization of α-Syn. We report the isolation and structural characterization of a synthetic human α-Syn fibril strain uniquely capable of seeding α-Syn fibrillization inside the nuclear compartment. In primary mouse cortical neurons, this strain provokes the buildup of NIIs with a remarkable morphology reminiscent of cat’s eye marbles (see video abstract). These α-Syn inclusions form giant patterns made of one, two, or three lentiform beams that span the whole intranuclear volume, pushing apart the chromatin. The input fibrils are no longer detectable inside the NIIs, where they become dominated by the aggregation of endogenous α-Syn. In addition to its phosphorylation at S129, α-Syn forming the NIIs acquires an epitope antibody reactivity profile that indicates its organization into fibrils, and is associated with the classical markers of α-Syn pathology p62 and ubiquitin. NIIs are also observed in vivo after intracerebral injection of the fibril strain in mice. Our data thus show that the ability to seed NIIs is a strain property that is integrally encoded in the fibril supramolecular architecture. Upstream alterations of cellular mechanisms are not required. In contrast to the lentiform TDP-43 NIIs, which are observed in certain frontotemporal dementias and which are conditional upon GRN or VCP mutations, our data support the hypothesis that the presence of α-Syn NIIs in MSA is instead purely amyloid-strain-dependent.

Efficient biodesulfurization of diesel oil by Gordonia sp. SC-10 with highly hydrophobic cell surfaces

Biodesulfurization is a promising, environmentally friendly method to desulfurize the organosulfur compounds in crude oils through the highly selective cleavage of carbon-sulfur bonds under mild reaction conditions. In this study, the behavior of a hydrophobic bacterium, Gordonia sp. SC-10, was evaluated in the presence of diesel oils. The biodesulfurization pathways, bacterium hydrophobicity, and cell ultrastructure were investigated, and the capability of strain SC-10 to desulfurize diesel oil was also studied. The results showed that strain SC-10 can desulfurize organosulfur compounds through sulfur-specific desulfurization pathways by producing corresponding hydroxylated products in oil-water polyphasic systems. Mycolic acids consisting of 47 and 58 carbon atoms chains were produced on the cell surface, and inclusion bodies were produced in the cells, both of which may improve the bioavailability of the substrates, thereby enhancing its adaptability to oil-water polyphasic systems. To our knowledge, this is the first report of intracellular inclusion body formation during biodesulfurization. Strain SC-10 also exhibited broad substrate specificity towards organosulfur compounds and effectively desulfurized diesel oils. The sulfur content in real-life diesel oil was reduced from 167.7 mg/L to 19.7 mg/L, with 88.3% of sulfur removed after five days of biodesulfurization. This study showed that Gordonia sp. SC-10 can be effectively used for the biodesulfurization of diesel oils.

Glucose-Limited Fed-Batch Cultivation Strategy to Mimic Large-Scale Effects in Escherichia coli Linked to Accumulation of Non-Canonical Branched-Chain Amino Acids by Combination of Pyruvate Pulses and Dissolved Oxygen Limitation

Insufficient mixing in large-scale bioreactors provokes gradient zones of substrate, dissolved oxygen (DO), pH, and other parameters. E. coli responds to a high glucose, low oxygen feeding zone with the accumulation of mixed acid fermentation products, especially formate, but also with the synthesis of non-canonical amino acids, such as norvaline, norleucine and β-methylnorleucine. These amino acids can be mis-incorporated into recombinant products, which causes a problem for pharmaceutical production whose solution is not trivial. While these effects can also be observed in scale down bioreactor systems, these are challenging to operate. Especially the high-throughput screening of clone libraries is not easy, as fed-batch cultivations would need to be controlled via repeated glucose pulses with simultaneous oxygen limitation, as has been demonstrated in well controlled robotic systems. Here we show that not only glucose pulses in combination with oxygen limitation can provoke the synthesis of these non-canonical branched-chain amino acids (ncBCAA), but also that pyruvate pulses produce the same effect. Therefore, we combined the enzyme-based glucose delivery method Enbase® in a PALL24 mini-bioreactor system and combined repeated pyruvate pulses with simultaneous reduction of the aeration rate. These cultivation conditions produced an increase in the non-canonical branched chain amino acids norvaline and norleucine in both the intracellular soluble protein and inclusion body fractions with mini-proinsulin as an example product, and this effect was verified in a 15 L stirred tank bioreactor (STR). To our opinion this cultivation strategy is easy to apply for the screening of strain libraries under standard laboratory conditions if no complex robotic and well controlled parallel cultivation devices are available.

Homeostatic p62 levels and inclusion body formation in CHCHD2 knockout mice.

Inactivation of constitutive autophagy results in the formation of cytoplasmic inclusions in neurones, but the relationship between impaired autophagy and Lewy bodies (LBs) remains unknown. α-Synuclein and p62, components of LBs, are the defining characteristic of Parkinson's disease (PD). Until now, we have analyzed mice models and demonstrated p62 aggregates derived from an autophagic defect might serve as 'seeds' and can potentially be a cause of LB formation. P62 may be the key molecule for aggregate formation. To understand the mechanisms of LBs, we analyzed p62 homeostasis and inclusion formation using PD model mice. In PARK22-linked PD, intrinsically disordered mutant CHCHD2 initiates Lewy pathology. To determine the function of CHCHD2 for inclusions formation, we generated Chchd2-knockout (KO) mice and characterized the age-related pathological and motor phenotypes. Chchd2 KO mice exhibited p62 inclusion formation and dopaminergic neuronal loss in an age-dependent manner. These changes were associated with a reduction in mitochondria complex activity and abrogation of inner mitochondria structure. In particular, the OPA1 proteins, which regulate fusion of mitochondrial inner membranes, were immature in the mitochondria of CHCHD2-deficient mice. CHCHD2 regulates mitochondrial morphology and p62 homeostasis by controlling the level of OPA1. Our findings highlight the unexpected role of the homeostatic level of p62, which is regulated by a non-autophagic system, in controlling intracellular inclusion body formation, and indicate that the pathologic processes associated with the mitochondrial proteolytic system are crucial for loss of DA neurones.

Nascent mutant Huntingtin exon 1 chains do not stall on ribosomes during translation but aggregates do recruit machinery involved in ribosome quality control and RNA.

Mutations that cause Huntington's Disease involve a polyglutamine (polyQ) sequence expansion beyond 35 repeats in exon 1 of Huntingtin. Intracellular inclusion bodies of mutant Huntingtin protein are a key feature of Huntington's disease brain pathology. We previously showed that in cell culture the formation of inclusions involved the assembly of disordered structures of mHtt exon 1 fragments (Httex1) and they were enriched with translational machinery when first formed. We hypothesized that nascent mutant Httex1 chains co-aggregate during translation by phase separation into liquid-like disordered aggregates and then convert to more rigid, amyloid structures. Here we further examined the mechanisms of inclusion assembly in a human epithelial kidney (AD293) cell culture model. We found mHttex1 did not appear to stall translation of its own nascent chain, or at best was marginal. We also found the inclusions appeared to recruit low levels of RNA but there was no difference in enrichment between early formed and mature inclusions. Proteins involved in translation or ribosome quality control were co-recruited to the inclusions (Ltn1 Rack1) compared to a protein not anticipated to be involved (NACAD), but there was no major specificity of enrichment in the early formed inclusions compared to mature inclusions. Furthermore, we observed co-aggregation with other proteins previously identified in inclusions, including Upf1 and chaperone-like proteins Sgta and Hspb1, which also suppressed aggregation at high co-expression levels. The newly formed inclusions also contained immobile mHttex1 molecules which points to the disordered aggregates being mechanically rigid prior to amyloid formation. Collectively our findings show little evidence that inclusion assembly arises by a discrete clustering of stalled nascent chains and associated quality control machinery. Instead, the machinery appear to be recruited continuously, or secondarily, to the nucleation of inclusion formation.

Autophagy in Neurodegenerative Diseases: A Hunter for Aggregates.

Cells have developed elaborate quality-control mechanisms for proteins and organelles to maintain cellular homeostasis. Such quality-control mechanisms are maintained by conformational folding via molecular chaperones and by degradation through the ubiquitin-proteasome or autophagy-lysosome system. Accumulating evidence suggests that impaired autophagy contributes to the accumulation of intracellular inclusion bodies consisting of misfolded proteins, which is a hallmark of most neurodegenerative diseases. In addition, genetic mutations in core autophagy-related genes have been reported to be linked to neurodegenerative diseases, such as Alzheimer’s disease, Parkinson’s disease, and Huntington’s disease. Conversely, the pathogenic proteins, such as amyloid β and α-synuclein, are detrimental to the autophagy pathway. Here, we review the recent advances in understanding the relationship between autophagic defects and the pathogenesis of neurodegenerative diseases and suggest autophagy induction as a promising strategy for the treatment of these conditions.

Aβ42 Double Mutant Inhibits Aβ42-Induced Plasma and Mitochondrial Membrane Disruption in Artificial Membranes, Isolated Organs, and Intact Cells.

Destabilization of plasma and inner mitochondrial membranes by extra- and intracellular amyloid β peptide (Aβ42) aggregates may lead to dysregulated calcium flux through the plasma membrane, mitochondrial-mediated apoptosis, and neuronal cell death in patients with Alzheimer's disease. In the current study, experiments performed with artificial membranes, isolated mitochondria, and neuronal cells allowed us to understand the mechanism by which a nonaggregating Aβ42 double mutant (designated Aβ42DM) exerts its neuroprotective effects. Specifically, we showed that Aβ42DM protected neuronal cells from Aβ42-induced accumulation of toxic intracellular levels of calcium and from apoptosis. Aβ42DM also inhibited Aβ42-induced mitochondrial membrane potential depolarization in the cells and abolished the Aβ42-mediated decrease in cytochrome c oxidase activity in purified mitochondrial particles. These results can be explained in terms of the amelioration by Aβ42DM of Aβ42-mediated changes in membrane fluidity in DOPC and cardiolipin/DOPC phospholipid vesicles, mimicking plasma and mitochondrial membranes, respectively. These observations are also in agreement with the inhibition by Aβ42DM of phospholipid-induced conformational changes in Aβ42 and with the fact that, unlike Aβ42, the Aβ42-Aβ42DM complex could not permeate into cells but instead remained attached to the cell membrane. Although most of the Aβ42DM molecules were localized on the cell membrane, some penetrated into the cytosol in an Aβ42-independent process, and, unlike Aβ42, did not form intracellular inclusion bodies. Overall, we provide a mechanistic explanation for the inhibitory activity of Aβ42DM against Aβ42-induced membrane permeability and cell toxicity and provide confirmatory evidence for its protective function in neuronal cells.

Ulcerative Colitis and Cytomegalovirus Infection: From A to Z

Despite multiple studies, the role of cytomegalovirus [CMV] infection in exacerbating the severity of inflammation in ulcerative colitis [UC], and its response to treatment, remain debatable. Additionally, the optimal diagnostic tests for CMV infection in the setting of UC relapse, and timing of antiviral treatment initiation, remain unclear. The challenge faced by gastroenterologists is to differentiate between an acute UC flare and true CMV colitis. It seems that the presence of CMV colitis, as defined by the presence of intranuclear or intracellular inclusion bodies on haematoxylin and eosin [H&E] staining and/or positive immunohistochemistry [IHC] assay on histology, is associated with more severe colitis. Patients with CMV infection and acute severe colitis are more resistant to treatment with corticosteroids than non-infected patients. This refractoriness to steroids is related to colonic tissue CMV viral load and number of inclusion bodies [high-grade CMV infection] which may have a pronounced effect on clinical outcomes and colectomy rates. Whereas many studies showed no effect for antiviral treatment on colectomy rates in CMV-infected UC patients, there was a significant difference in colectomy rates of patients with high-grade infection who received anti-viral therapy compared with those who did not receive treatment. It was therefore proposed that high-grade CMV disease indicates that the virus is acting as a pathogen, whereas in those with low-grade CMV disease, the severity of IBD itself is more likely to influence outcome. The different algorithms that have been put forward for the management of patients with UC and concomitant CMV infection are discussed.

糖尿病性ケトアシドーシスを契機に診断された孤発型エオジン好性神経核内封入体病の1例(Incidental diagnosis of sporadic neuronal intracellular inclusion disease in an elderly woman with diabetic ketoacidosis: a case report)

要旨 患者は77歳の女性。2型糖尿病の基礎疾患があり，近医に定期通院中であった。入院日の2日前から意識障害が出現，症状が進行増悪し，緊急入院当日になりJapan coma scale 300の意識障害を呈したため家人により救急要請され当院救急外来に搬送された。来院時の頭部CT，MRI検査では急性期脳血管障害の所見はなく，血液・尿検査結果から尿路感染症を契機に発症した糖尿病性ケトアシドーシスと診断した。意識障害の原因として高血糖性昏睡が考えられた。集学的治療管理目的に入院し，各病態に対して適切な治療介入を行った。しかしながら24時間以上が経過しても意識障害が遷延した。入院時に撮影した頭部MRI検査結果を見直したところ，拡散強調画像にて両側皮質下白質に特徴的な線状あるいは弧状の高信号域がみられ，神経核内封入体病が疑われた。全身管理を継続し，その後リハビリテーション目的に他院へ転院した。エオジン好性神経核内封入体病は，神経細胞核内にエオジン好性封入体を形成し，軽度認知機能低下症状から，脳卒中様症状など多彩な臨床像を呈する神経変性疾患である。救急医にとって本疾患は馴染みが薄く，特徴的な頭部MRI画像所見であっても知らなければ容易に見逃してしまう可能性がある。高齢者の割合増加とともに救急搬送が増加している今日の救急医療において，本疾患の認知が重要である。

Wnt5a Belongs to the Lysosomal Cholesterol-Sensing Machinery that Controls mTORC1

The Wnt ligand, Wnt5a limits cellular cholesterol accumulation, however, it role in atherosclerosis is unknown. Here, we show that mice deleted for Wnt5a in vascular smooth muscle cells (VSMCs) developed atherosclerosis lesions when fed a cholesterol-rich diet. VSMCs accumulated cholesterol in enlarged endosome/lysosome (LELs), and lipofuscin containing vesicles. We identified Wnt5a, as a member of the nutrient/energy/stress sensor, mTORC1 scaffolding complex, which drives lysosomal fonction and promotes cholesterol trafficking. By decreasing mTORC1 activity, Wnt5a senses changes in dietary cholesterol supply, promotes LELs cholesterol egress to the endoplasmic reticulum (ER), and protects against atherosclerosis. Moreover, Wnt5a binds cholesterol-rich membranes and interacts with the polytopic membrane-bound Niemann–Pick C1 (NPC1) and soluble Niemann–Pick C2 (NPC2), two lysosomal proteins that regulate cholesterol export from LELs. Consequently, absence of Wnt5a decoupled mTORC1 from variations in LELs sterol levels, and this resulted in accumulation of large intracellular inclusion bodies, large LELs, decreased cholesterol content in the ER, activation of the sterol regulatory element-binding protein-2 (SREBP-2) a master regulator of cholesterol biosynthesis. These results reveal an unexpected function of the Wnt5a pathway, and provide a conceptually new basis for future drug development to prevent cholesterol accumulation, atherosclerosis, and lysosomal storage diseases.

Centenary of Tretiakoff’s thesis on the morphology of Parkinson’s disease, evolved on the grounds of encephalitis lethargica pathology

ABSTRACTIn his Thèse de Paris (1919) Konstantin Tretiakoff (1892–1956) described the two main morphological lesions in Parkinson’s disease: the loss of pigmented nerve cells in the Substantia nigra and the intracellular inclusion bodies in idiopathic paralysis agitans, calling them “Corps de Lewy,” which already had been described by F. H. Lewy in 1912. Tretiakoff’s findings on idiopathic Parkinson’s disease were confirmed years later by Rolf Hassler in his dissertation on anatomy and pathology of Substantia nigra in Berlin (1938, 1939). German authors in the 1920s underestimated the significance of both findings (Bielschowsky, 1922; Lewy 1923/1924; Spatz 1927), especially Lewy himself. Lewy (1923) and other German neurologists and neuropathologists like Felix Stern (1922, 1928), Goldstein (1922), and Spatz (1927; Luksch & Spatz, 1923) acknowledged the typical Nigra-lesions only for postencephalitic Parkinsonism. It is argued that Tretiakoff’s selective attention for the Substantia nigra was guided by the frequency of epidemic encephalitis lethargica and its preponderance of nigral pathology. This impression can be derived from Tretiakoff’s early paper on that disease (Marie & Tretiakoff, 1918) and from Paul Foley’s opus magnum (2018). Two outstanding neurologists dedicated to this issue are called into memory: Gabrielle Lévy, the successor of Tretiakoff in the Salpêtrière laboratory, and Felix Stern, who died in 1942 as a victim of Nazi terror. The eponym Lewy-bodies went back to Lafora and Tretiakoff (“Corps de Lewy”). Newly expressed doubts about Lewy’s primacy or Lafora’s credit for the eponym (Lafora-bodies since 1911) can be refuted with the studies of Greenfield and Bosanquet (1953) and Greenfield (1963) by illustrating their different staining properties.

Global Biogeographic Distribution Patterns of Thermoacidophilic Verrucomicrobia Methanotrophs Suggest Allopatric Evolution.

Thermoacidophilic methane-oxidizing Verrucomicrobia of the candidate genus Methylacidiphilum represent a bacterial taxon adapted to highly acidic (pH 1–4) and moderate temperature (∼65°C) methane-containing geothermal environments. Their apparent ubiquity in acidic terrestrial volcanic areas makes them ideal model organisms to study prokaryotic biogeography. Three Methylacidiphilum species isolated from distantly-separated geothermal regions in Russia, New Zealand, and Italy were previously described. We have explored the intra-taxon phylogenetic patterns of these organisms based on comparative genome analyses and phenotypic comparisons with six new Verrucomicrobia methanotroph isolates from other globally-separated acidic geothermal locations. Comparison of rRNA and particulate methane monooxygenase (pmoCAB) operon sequences indicates a close phylogenetic relationship among the new isolates as well as with the previously characterized strains. All share similar cell morphology including the presence of extensive intracellular inclusion bodies and lack of intracellular membrane systems, which are typical for proteobacterial methanotrophs. However, genome sequence comparisons and concatenated MLST-based phylogenetic analyses separate the new isolates into three distinct species-level groups. Three recently processed isolates from the Azores (each from geographically-separate hot springs within the region) and a single isolate from Iceland are highly similar, sharing more than 88% in silico genome homology with each other as well as with the previous isolate, Methylacidiphilum fumariolicum strain SolV, from Italy. These appear to constitute a distinct European/Atlantic clade. However, two of the new isolates – one from the Yellowstone National Park (United States) and another from The Philippines – constitute separate and novel Methylacidiphilum species. There is no clear correlation between fatty acid profiles and geographic distance between origins, or any phylogenetic relationship. Serological analysis using antiserum raised against M. kamchatkense strain Kam1 revealed large differences in the degree of cross-reactivity with no correlation with other factors. However, the genetic distance between the strains does correlate to the distance between their geographic origins and suggests a global biogeographic pattern shaped by an isolation-by-distance mechanism. These results further confirm terrestrial geothermal springs as isolated islands featuring allopatric prokaryotic speciation.

The metastability of the proteome of spinal motor neurons underlies their selective vulnerability in ALS

Amyotrophic lateral sclerosis (ALS) is a heterogeneous motor neuron disease with familial forms linked to numerous mutations in a range of genes. The resulting variant proteins, including SOD1, TDP-43, and FUS, disturb protein homeostasis in a variety of ways and lead to the formation of intracellular inclusion bodies that are characteristic of different neuropathological subtypes of the disease. These inclusions are made up of scores of proteins that do not appear at first to share obvious characteristics other than coaggregation. Recent evidence, however, suggests that these aggregating proteins can be characterized as being supersaturated in spinal motor neurons, as they exhibit cellular concentrations exceeding their solubilities. Here, we show that the average supersaturation of the entire spinal motor neuron proteome is greater than that of the ALS-resistant oculomotor neurons, suggesting that the vulnerability of spinal motor neurons is linked to the overall metastability of their proteome against aggregation. Consistently, ALS expression data suggest that affected neurons respond to pathology by transcriptional downregulation of supersaturated proteins, including specifically ion channels. These results identify a mechanism by which protein homeostasis imbalance leads to inclusion body formation in ALS, and to a disruption of other processes dependent on proteins that are supersaturated, thereby resulting in the dysfunctional excitability alterations observed in vivo.