2022-07-16

陰謀分析_ワク05

スパイクたんぱく質はDNA修復とV(D)J遺伝子再構成を障害する(in Vitro)

(V(D)J遺伝子再構成（VDJいでんしさいこうせい、英：V(D)J recombinationまたはsomatic recombination）は、免疫システム内の免疫グロブリン（Ig）・TCR（T細胞受容体）生成の初期ステージにおける遺伝子再構成の仕組み。初期のリンパ組織（骨髄ではB細胞、胸腺ではT細胞）で起こる。V(D)J遺伝子再構成は、骨髄や胸腺でのリンパ球の遺伝子断片（V、D、J）のランダムな組み合わせである。抗体やTCRをコードするDNAは多数の断片として染色体の上に並んでいる。これらのDNA断片はリンパ球の分化の過程で連結され、完全なDNAとなる。いろんな遺伝子をランダムに選べるので、いろんなタンパク質をつくり、いろんな抗原（バクテリア、ウイルス、寄生菌、腫瘍、花粉など）に対抗することができる。by Wilipedia)

SARS–CoV–2 Spike Impairs DNA Damage Repair and Inhibits V(D)J Recombination In Vitro, Received: 20 August 2021

Severe acute respiratory syndrome coronavirus 2 (SARS–CoV–2) has led to the coron- avirus disease 2019 (COVID–19) pandemic, severely affecting public health and the global economy. Adaptive immunity plays a crucial role in ﬁghting against SARS–CoV–2 infection and directly in- ﬂuences the clinical outcomes of patients. Clinical studies have indicated that patients with severe COVID–19 exhibit delayed and weak adaptive immune responses; however, the mechanism by which SARS–CoV–2 impedes adaptive immunity remains unclear. Here, by using an in vitro cell line, we report that the SARS–CoV–2 spike protein signiﬁcantly inhibits DNA damage repair, which is required for effective V(D)J recombination in adaptive immunity. Mechanistically, we found that the spike protein localizes in the nucleus and inhibits DNA damage repair by impeding key DNA repair protein BRCA1 and 53BP1 recruitment to the damage site. Our ﬁndings reveal a potential molecular mechanism by which the spike protein might impede adaptive immunity and underscore the potential side effects of full-length spike-based vaccines.

2022-07-16

陰謀分析_ワク04

SARS-Cov2 関連書記論文プリオン、アルツハイマー

SARS-CoV-2 Spike Protein Impairs Endothelial Function via Downregulation of ACE 2, 2021/4/30

SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) infection relies on the binding of S protein (Spike glycoprotein) to ACE (angiotensin converting enzyme) 2 in the host cells. Vascular endothelium(中胚葉起源の上皮) can be infected by SARS-CoV-2, which triggers mitochondrial reactive oxygen species(ROS, 血中活性酸素種, produced by mitochondria) production and glycolytic shift(解糖シフト, glycolysis 解糖系とは、生体内に存在する生化学反応経路の名称であり、グルコースをピルビン酸などの有機酸に分解し、グルコースに含まれる高い結合エネルギーを生物が使いやすい形に変換していくための代謝過程である。ほとんど全ての生物が解糖系を持っており、もっとも原始的な代謝系とされている). Paradoxically, ACE2 is protective in the cardiovascular(心血管) system, and SARS-CoV-1 S protein promotes lung injury by decreasing the level of ACE2 in the infected lungs. In the current study, we show that S protein alone can damage vascular endothelial cells (ECs) by downregulating ACE2 and consequently inhibiting mitochondrial function.

SARS-CoV-2 targets neurons of 3D human brain organoids, 2020

COVID-19 pandemic caused by SARS-CoV-2 infection is a public health emergency. COVID-19 typically exhibits respiratory illness. Unexpectedly, emerging clinical reports indicate that neurological symptoms continue to rise, suggesting detrimental effects of SARS-CoV-2 on the central nervous system (CNS). Here, we show that a Düsseldorf isolate of SARS-CoV-2 enters 3D human brain organoids(試験管内など生体外、3次元的につくられた臓器である) within 2 days of exposure. We identified that SARS- CoV-2 preferably targets neurons of brain organoids. Imaging neurons of organoids reveal that SARS-CoV-2 exposure is associated with altered distribution of Tau from axons to soma, hyper-phosphorylation, and apparent neuronal death. Our studies, therefore, provide initial insights into the potential neurotoxic effect of SARS-CoV-2 and emphasize that brain organoids could model CNS pathologies of COVID-19.

SARS-CoV-2 prion-like domains in spike proteins enable higher affinity to ACE2, 2020/3/29

Currently, the world is struggling with the coronavirus disease 2019 (COVID-19) pandemic, caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Prion-like domains are critical for virulence and the development of therapeutic targets; however, the prion- like domains in the SARS-CoV-2 proteome have not been analyzed. In this in silico study, using the PLAAC algorithm, we identified the presence of prion-like domains in the SARS-CoV-2 spike protein. Compared with other viruses, a striking difference was observed in the distribution of prion-like domains in the spike protein, since SARS-CoV-2 was the only coronavirus with a prion-like domain found in the receptor-binding domain of the S1 region of the spike protein. The presence and unique distribution of prion-like domains in the SARS-CoV-2 receptor-binding domains of the spike protein is particularly interesting, since although the SARS-CoV-2 and SARS-CoV S proteins share the same host cell receptor, angiotensin-converting enzyme 2 (ACE2), SARS-CoV-2 demonstrates a 10- to 20-fold(10-20倍) higher affinity for ACE2. Finally, we identified prion-like domains in the α1 helix of the ACE2 receptor that interact with the viral receptor-binding domain of SARS-CoV-2. Taken together, the present findings indicate that the identified prion-like domains (PrDs) in the SARS-CoV-2 receptor-binding domain (RBD) and ACE2 region that interact with RBD have important functional roles in viral adhesion and entry.

Prion protein as a toxic acceptor of amyloid-β oligomers

The initial report that cellular prion protein (PrPC) mediates toxicity of Amyloid-β (Aβ) species linked to Alzheimer’s disease was initially treated with scepticism, but growing evidence supports this claim. That there is a high-affinity interaction is now clear and its molecular basis is being unravelled whilst recent studies have identified possible down-stream toxic mechanisms. Determination of the clinical significance of such interactions between PrPC and disease-associated Aβ species will require experimental medicine studies in humans. Compounds that inhibit PrP-dependent Aβ toxicity are starting to be trialled in humans and, although it is clear that only a fraction of Alzheimer’s disease toxicity could be governed by PrPC, a partial but still therapeutically useful role in human disease may soon be testable.

SARS-CoV-2 spike protein interactions with amyloidogenic proteins: Potential clues to neurodegeneration, 2021/3/4

The post-infection of COVID-19 includes a myriad of neurologic symptoms including neurodegeneration. Protein aggregation in brain can be considered as one of the important reasons behind the neuro- degeneration. SARS-CoV-2 Spike S1 protein receptor binding domain (SARS-CoV-2 S1 RBD) binds to heparin and heparin binding proteins. Moreover, heparin binding accelerates the aggregation of the pathological amyloid proteins present in the brain. In this paper, we have shown that the SARS-CoV-2 S1 RBD binds to a number of aggregation-prone, heparin binding proteins including Aβ, α-synuclein, tau, prion, and TDP-43 RRM. These interactions suggests that the heparin-binding site on the S1 protein might assist the binding of amyloid proteins to the viral surface and thus could initiate aggregation of these proteins and ﬁnally leads to neurodegeneration in brain. The results will help us to prevent future outcomes of neurodegeneration by targeting this binding and aggregation process

Transmission and spreading of tauopathy in transgenic mouse brain, 2009/7

Hyperphosphorylated tau makes up the filamentous intracellular inclusions of several neurodegenerative diseases, including Alzheimer's disease. In the disease process neuronal tau inclusions first appear in transentorhinal cortex, from where they appear to spread to hippocampal formation and neocortex 2. Cognitive impairment becomes manifest when inclusions reach the hippocampus, with abundant neocortical tau inclusions and extracellular β-amyloid deposits being the defining pathological hallmarks of Alzheimer's disease. Abundant tau inclusions, in the absence of β-amyloid deposits, define Pick's disease, progressive supranuclear palsy, corticobasal degeneration and other diseases 1. Tau mutations cause familial forms of frontotemporal dementia, establishing that tau protein dysfunction is sufficient to cause neurodegeneration and dementia 3-5. Thus, transgenic mice expressing mutant (e.g. P301S) human tau in nerve cells exhibit the essential features of tauopathies, including neurodegeneration and abundant filaments made of hyperphosphorylated tau protein 6,7. In contrast, mouse lines expressing single isoforms of wild-type human tau do not produce tau filaments or display neurodegeneration 7,8. Here we have used tau-expressing lines to investigate whether experimental tauopathy can be transmitted. We show that the injection of brain extract from mutant P301S tau-expressing mice into the brain of transgenic wild-type tau-expressing animals induces the assembly of wild-type human tau into filaments and the spreading of pathology from the site of injection to neighbouring brain regions.

2022-07-16

陰謀分析_ワク03

» 免疫システムを担う細胞の種類セレンクリニック(がん免疫療法セレンメソッド外来) (serenclinic.jp)

【リンパ球（T・B・NK細胞）】

★　T細胞

ウイルスなどに感染した細胞を見つけて排除します。T細胞は、ヘルパーＴ細胞、キラーT細胞、制御性T細胞の3種類があり、それぞれ司令塔、殺し屋、クローザーの役割があります。

①　キラーT細胞は樹状細胞から抗原情報を受け取り、ウィルスが感染した細胞やがん細胞にとりつき、排除する、といういわゆる「殺し屋」の働きを持っています。

② 　ヘルパーT細胞は、樹状細胞やマクロファージから異物の情報（抗原）を受け取り、サイトカインなどの免疫活性化物質などを産生します。

③　制御性T細胞は、キラーT細胞が正常細胞へ攻撃をしないよう、キラーＴ細胞の働きを抑制したり、免疫反応を終了に導く、野球でいう「クローザー」の役割を担っています。

④　αβT細胞（アルファベータＴ細胞）は、αβT細胞療法に利用される、α鎖とβ鎖からなるT細胞受容体を有するT細胞の総称です。抗CD3抗体とIL-2を使用して選択的に増殖させることが可能です。αβT細胞療法は、一般に活性化自己リンパ球療法（LAK療法）とよばれている免疫細胞療法の一種です。

⑤　γδT細胞（ガンマデルタT細胞）は、α鎖、β鎖と呼ばれる2つの糖タンパク質から構成されるT細胞受容体を持つＴ細胞の総称です。γδT細胞は、αβT細胞と比べると少数ですが、この末梢血中に存在するγδT細胞には、がん細胞を認識して攻撃する能力があることが明らかになっています。

⑥　ナチュラルキラーT細胞（NKT細胞）は、T細胞とナチュラルキラー細胞（NK細胞）の両方の特徴を持つＴ細胞の亜種です。NKT細胞は末梢血中T細胞のわずか0.1%程度しか存在しません。活性化されたNKT細胞は、サイトカイン（IFN-γなど）を産生したり、Fasリガンドやパーフォリン・グランザイムによるがん細胞への障害活性を示します。

★　B細胞

B細胞は骨髄に存在して、抗体を産生する免疫細胞です。血液の元となる細胞（造血幹細胞）から作られ、樹状細胞の指令を受けると、外敵や異物を攻撃する「抗体」を作り、異物の排除を手助けします。また、B細胞は、細胞ごとに作る抗体の種類が決まっています。あるB細胞が作り出す抗体に適合した外敵が出現した場合にのみ、そのB細胞は活性化して、抗体を産生します。

★　NK（ナチュラルキラー）細胞

いつもからだの中をパトロールしています。ウイルスに感染した細胞などを発見すると単独で攻撃をしかけます。T細胞とは異なり、他からの指示を必要とせず、一人で外敵や異物を攻撃できるため、生まれつき（natural）の殺し屋（killer）という名前が付けられています。

モノクローナル抗体（Monoclonal antibody）とは

単一の抗体を産生する細胞と分裂と成長をし続ける細胞を融合させ、実験室内で単一な抗体を産生し続ける細胞をつくり、この細胞によって産生される均一な性質をもつ抗体をいいます。このような細胞系は特定のたん白の特定の領域(エピトープ）に結合する抗体を産生します。

open conformation

(可動領域をもつタンパク質などの分子がリガンド結合部位を露出している状態) オープン構造, 開構造

closed conformation

(可動領域をもつタンパク質などの分子がリガンド結合部位を隠している状態) 閉構造