The clinical manifestations resulting from AD include memory and cognitive impairment, anxiety, confusion, language difficulties, and mood swings. Current treatments including acetylcholine esterase inhibitors or NMDA receptors antagonists are somehow symptomatic, showing side-effects and may not heal the disease. Despite extensive considerations, an efficient therapeutic has remained elusive thus far. AD is characterized by the deposition of β-amyloid (Aβ) protein oligomers and intracellular neurofibrillary tangles (NFTs) composed of hyperphosphorylated tau protein (P-tau), serving as the primary pathological signs of AD. There have been various strategies to eliminate pathogenic amyloids. The most important antibody against neurotoxic amyloid is Adecunumab by Biogen, which showed disappointing results; especially at later stages of the disease. Although β-amyloids are indeed neurotoxic, there are increasing evidence that tau abnormalities overlap better with AD development. Tau hyperphosphorylation and aggregation is a long-lasting process; sometimes over years! Thus, this is of crucial importance to demonstrate which phosphorylation event triggers tau pathogenicity. We have previously shown that phosphorylated tau at the Thr231-Pro232 motif in cis conformation is extremely neurotoxic and yields the loss of normal tau functions. However, we have recently found that neurotoxic pT231-tau conformer in human brain is different from rodents. We had a few shots in the dark to reach to the specific pT231-tau conformer, which is pathogenic in human neurons. We have generated a fully human monoclonal antibody (scFv domain) against the pathogenic conformer and have shown that antibody may recognize pathogenic pT231-tau species and suppress tau pathogenicity and neurodegeneration in AD human neurons (patent # US 10,570,195 B2).
The clinical manifestations resulting from AD include memory and cognitive impairment, anxiety, confusion, language difficulties, and mood swings. Current treatments including acetylcholine esterase inhibitors or NMDA receptors antagonists are somehow symptomatic, showing side-effects and may not heal the disease. Despite extensive considerations, an efficient therapeutic has remained elusive thus far. AD is characterized by the deposition of β-amyloid (Aβ) protein oligomers and intracellular neurofibrillary tangles (NFTs) composed of hyperphosphorylated tau protein (P-tau), serving as the primary pathological signs of AD. There have been various strategies to eliminate pathogenic amyloids. The most important antibody against neurotoxic amyloid is Adecunumab by Biogen, which showed disappointing results; especially at later stages of the disease. Although β-amyloids are indeed neurotoxic, there are increasing evidence that tau abnormalities overlap better with AD development. Tau hyperphosphorylation and aggregation is a long-lasting process; sometimes over years! Thus, this is of crucial importance to demonstrate which phosphorylation event triggers tau pathogenicity. We have previously shown that phosphorylated tau at the Thr231-Pro232 motif in cis conformation is extremely neurotoxic and yields the loss of normal tau functions. However, we have recently found that neurotoxic pT231-tau conformer in human brain is different from rodents. We had a few shots in the dark to reach to the specific pT231-tau conformer, which is pathogenic in human neurons. We have generated a fully human monoclonal antibody (scFv domain) against the pathogenic conformer and have shown that antibody may recognize pathogenic pT231-tau species and suppress tau pathogenicity and neurodegeneration in AD human neurons (patent # US 10,570,195 B2).

Tau is a member of the microtubule-associated family of proteins (MAPs) which are expressed predominantly in the brain (mainly founds in neurons but is also present at low levels in glial cells). This protein is encoded by a single gene, MAPT, located on human chromosome 17. In its native state, tau is present in a stable, unfolded monomeric conformation and it is a hydrophilic and highly soluble protein. Tau’s primary functions include the stabilization of microtubules and the coordinated movement of molecules along the microtubule and microtubule assembly. Tau is a phosophoprotein that a normal level of phosphorylation is required for its optimal function, whereas the hyperphosphorylated state makes tau to lose its biological activity. This protein has 85 phosphorylation sites in its human longest isoform. Normal brain tau contains 2-3 moles of phosphate per mole of the protein. In AD brain, tau is abnormally hyperphosphorylated at least three-fold greater than normal tau, this alteration leads to Neurofibrillary tangle (NFT) formation, a histopathological hallmark of the disease. The abnormal hyperphosphorylation of tau is also a hallmark of several other related neurodegenerative disorders, called Tauopathies. Tau phosphorylation at different sites has a different impact on its biological function and on its pathogenic role. An in vitro study demonstrated that phosphorylation of tau at many sites such as Ser262, Thr231, and Ser235 inhibits its binding to microtubules. Another study suggests that Ser199/Ser202/Thr205, Thr212, Thr231/Ser235, Ser262/Ser356, and Ser422 are among the critical phosphorylation sites that convert tau to an inhibitory molecule that sequesters normal microtubule-associated proteins from microtubule. Further phosphorylation at Thr231, Ser396, and Ser422 promotes self-aggregation of tau into filaments.
Recently, we have reported that phosphorylated tau at Thr231 is extremely neurotoxic and early driver of neurodegeneration upon tauopathies, such as AD. Our preclinical observations based on animal mouse models have clearly demonstrated that immunotherapy employing the pT231-tau mouse monoclonal antibody suppresses neurodegeneration in those TBI mouse models. Thus, we have generated a fully human pT231-tau antibody and examined the efficacy in suppressing neurodegeneration in transgenic AD mouse models and have shown our antibody efficiently neutralizes the pathogenic p-tau epitope.


The effect of antibody treatment (i.v.) on the ability of memory in the retention day. Color maps collapsed across all animals in each group (mean groups), showing the percent time in each location of the swimming pool during the no-platform probe test. The location of the platform is marked by a white box. Total time (s) that animals in each experimental group spent in the target zone were evaluated. Data are represented as mean ± SEM for 6 mice. One-way ANOVA followed by Tukey’s post hoc comparisons tests were performed.

To examine the anxiolytic properties of our mAb, we performed elevated-plus maze test in AD mice models. The healthy control animals explored significantly less time in the open arms than AD animals (p = 0.009 or p - 0.01) mice. Moreover, mAb-treated groups, similar to the control group, spent significantly less time in the open arms (p - 0.001) compared with AD groups. AD animals displayed more total open arm entries than the control and mAb-treated AD mice. As a result, all AD mice, exploring the two open arms, showed anxiety/risk-taking behavior by contrast, mAb-treated AD mice displayed minimal anxious behavior. Thus, our mAb not only eliminates pathogenic pT231-tau but also restores behavioral deficits triggered by AD.
Moreover, immunotherapy with our pT231-tau mAb improved ultrastructural consequences triggered by AD. It is clear that pathogenic pT231-tau is associated with neurodegenerative outcomes and microtubule and mitochondrial disruption. To understand the effectiveness of our mAb on neurodegenerative pathologies triggered by AD, we treated the animal models with anti pT231-tau mAb. We have shown that while AD pathogenesis result in brain ultrastructure disruption, our mAb treatment effectively eliminated tau pathology and structural defects in axonal microtubules (MTs; blue open arrows) and mitochondria (MI; red filled arrows).


Furthermore, we have clearly confirmed that while there is a profound tau pathology in AD animal models, the antibody efficiently suppresses tau hyperphosphorylation in the animal models (AT8 as early and PHF-1 as late tau pathology markers)
Also, we performed immunotherapy assessments on human AD neurons generated from fAD subjects iPSCs. Our preclinical observations have demonstrated that while AD neurons degenerated upon aging, pretreatment the culture with our pT231-tau human antibody suppresses neural cell death efficiently (left: control cells; middle: AD neurons; right panel: AD neurons treated with anti pT231-tau human antibody).


We have also co-immunostained human AD postmortem brain with our human antibody & mouse cis pT231-tau antibody and have found a prominent pT231-tau (but not cis p-tau ) epitope in those brains while there was not any positive signal in healthy control brains. There is a gradual increase in the pT231-tau epitope confirmed by immunostaining of human AD postmortem brains.

Moreover, we performed immunoblotting analysis on human AD and healthy brain extracts using our antibody and compared the results with anti cis pT231-tau mouse monoclonal antibody. Immunoblots of AD and healthy control human brain extracts stained with anti cis pT231-tau mouse monoclonal antibody (A) and our anti pT231-tau human monoclonal antibody (B). As shown in the blots, there is no significant difference between control and AD brain extracts when stained with cis p-tau antibody. Interestingly, our human pT231-tau recognizes six tau isoforms only in AD brain extract; demonstrating that the antibody specifically binds to pathogenic tau species.

Tau is a member of the microtubule-associated family of proteins (MAPs) which are expressed predominantly in the brain (mainly founds in neurons but is also present at low levels in glial cells). This protein is encoded by a single gene, MAPT, located on human chromosome 17. In its native state, tau is present in a stable, unfolded monomeric conformation and it is a hydrophilic and highly soluble protein. Tau’s primary functions include the stabilization of microtubules and the coordinated movement of molecules along the microtubule and microtubule assembly. Tau is a phosophoprotein that a normal level of phosphorylation is required for its optimal function, whereas the hyperphosphorylated state makes tau to lose its biological activity. This protein has 85 phosphorylation sites in its human longest isoform. Normal brain tau contains 2-3 moles of phosphate per mole of the protein. In AD brain, tau is abnormally hyperphosphorylated at least three-fold greater than normal tau, this alteration leads to Neurofibrillary tangle (NFT) formation, a histopathological hallmark of the disease. The abnormal hyperphosphorylation of tau is also a hallmark of several other related neurodegenerative disorders, called Tauopathies. Tau phosphorylation at different sites has a different impact on its biological function and on its pathogenic role. An in vitro study demonstrated that phosphorylation of tau at many sites such as Ser262, Thr231, and Ser235 inhibits its binding to microtubules. Another study suggests that Ser199/Ser202/Thr205, Thr212, Thr231/Ser235, Ser262/Ser356, and Ser422 are among the critical phosphorylation sites that convert tau to an inhibitory molecule that sequesters normal microtubule-associated proteins from microtubule. Further phosphorylation at Thr231, Ser396, and Ser422 promotes self-aggregation of tau into filaments.
Recently, we have reported that phosphorylated tau at Thr231 is extremely neurotoxic and early driver of neurodegeneration upon tauopathies, such as AD. Our preclinical observations based on animal mouse models have clearly demonstrated that immunotherapy employing the pT231-tau mouse monoclonal antibody suppresses neurodegeneration in those TBI mouse models. Thus, we have generated a fully human pT231-tau antibody and examined the efficacy in suppressing neurodegeneration in transgenic AD mouse models and have shown our antibody efficiently neutralizes the pathogenic p-tau epitope.


The effect of antibody treatment (i.v.) on the ability of memory in the retention day. Color maps collapsed across all animals in each group (mean groups), showing the percent time in each location of the swimming pool during the no-platform probe test. The location of the platform is marked by a white box. Total time (s) that animals in each experimental group spent in the target zone were evaluated. Data are represented as mean ± SEM for 6 mice. One-way ANOVA followed by Tukey’s post hoc comparisons tests were performed.

To examine the anxiolytic properties of our mAb, we performed elevated-plus maze test in AD mice models. The healthy control animals explored significantly less time in the open arms than AD animals (p = 0.009 or p - 0.01) mice. Moreover, mAb-treated groups, similar to the control group, spent significantly less time in the open arms (p - 0.001) compared with AD groups. AD animals displayed more total open arm entries than the control and mAb-treated AD mice. As a result, all AD mice, exploring the two open arms, showed anxiety/risk-taking behavior by contrast, mAb-treated AD mice displayed minimal anxious behavior. Thus, our mAb not only eliminates pathogenic pT231-tau but also restores behavioral deficits triggered by AD.
Moreover, immunotherapy with our pT231-tau mAb improved ultrastructural consequences triggered by AD. It is clear that pathogenic pT231-tau is associated with neurodegenerative outcomes and microtubule and mitochondrial disruption. To understand the effectiveness of our mAb on neurodegenerative pathologies triggered by AD, we treated the animal models with anti pT231-tau mAb. We have shown that while AD pathogenesis result in brain ultrastructure disruption, our mAb treatment effectively eliminated tau pathology and structural defects in axonal microtubules (MTs; blue open arrows) and mitochondria (MI; red filled arrows).


Furthermore, we have clearly confirmed that while there is a profound tau pathology in AD animal models, the antibody efficiently suppresses tau hyperphosphorylation in the animal models (AT8 as early and PHF-1 as late tau pathology markers)
Also, we performed immunotherapy assessments on human AD neurons generated from fAD subjects iPSCs. Our preclinical observations have demonstrated that while AD neurons degenerated upon aging, pretreatment the culture with our pT231-tau human antibody suppresses neural cell death efficiently (left: control cells; middle: AD neurons; right panel: AD neurons treated with anti pT231-tau human antibody).


We have also co-immunostained human AD postmortem brain with our human antibody & mouse cis pT231-tau antibody and have found a prominent pT231-tau (but not cis p-tau ) epitope in those brains while there was not any positive signal in healthy control brains. There is a gradual increase in the pT231-tau epitope confirmed by immunostaining of human AD postmortem brains.

Moreover, we performed immunoblotting analysis on human AD and healthy brain extracts using our antibody and compared the results with anti cis pT231-tau mouse monoclonal antibody. Immunoblots of AD and healthy control human brain extracts stained with anti cis pT231-tau mouse monoclonal antibody (A) and our anti pT231-tau human monoclonal antibody (B). As shown in the blots, there is no significant difference between control and AD brain extracts when stained with cis p-tau antibody. Interestingly, our human pT231-tau recognizes six tau isoforms only in AD brain extract; demonstrating that the antibody specifically binds to pathogenic tau species.
OUR TEAM

I have had a long-term and intensive interest in brain dysfunctioning mechanisms and possible therapeutics. In particular, I’ve been investigating molecular mechanisms of tau pathogenicity and neurodegeneration. During my MSc, I examined the effects of Calcium tau projection domain; whose results was published in Journal of Neuroscience Research. Then I moved to Tokyo Metropolitan University to do my PhD under supervision of Prof. Shin ichi Hisanaga. I have shown that tau phosphorylation at AT8 domain would tune mitochondrial transport; whose results were published in Journal of Neuroscience. Then I started my postdoctoral project at Harvard Medical School under mentorship of very well-known scientist: Prof. Kun Ping Lu. During my postdoc, I examined tau pathogenicity upon conformational changes at Thr231-Pro232 domain. We have shown that phosphorylated tau at Thr231 in the cis conformation is extremely neurotoxic and early driver of neurodegeneration upon Traumatic Brain Injury in TBI mouse models.
Upon my return to Iran, I pursued my research at Royan Institute as a faculty member and Head of Department of Brain and Cognitive Sciences. I am now supervising over 56 PhD, MD, and MSc students; focusing on tau pathogenicity and neurodegeneration.
We co-overexpressed GFP-tau & Cdk5-P25 in SH-SY5Y cells and examined tau pathogenicity in a confocal microscope. We found p-tau overexpression kills the neural cells:

However, mutant T231A p-tau over expression is not pathogenic:

These findings are indeed remarkable; demonstrating out of ~85 tau phosphorylation sites, Thr231 is of crucial importance.
On the other hand, we have found that while cis pT231-tau is extremely neurotoxic in rodents, it does not accumulate in human neurons upon stress conditions and is not pathogenic:

Koorosh Shahpasand
CEO | CTO
Associate Professor and Head of Department of Brain and Cognitive Science at, Royan Institute, Iran
International Scientific Awards:
NIRG-395611 from Alzheimer’s Association at Chicago, USA (2016)
Selected Neuroscientist from Brain Protein Aging Program at Osaka, Japan (2016)

ALI TARAGHI JAH
CHAIRMAN
Business and Technology Management

HOSSEIN PAKDAMAN
CSA
Professor of Neurology, President of Iranian Neurological Association Board Since 1991Director of Iranian Neurological Board Examination Since 1978

MEHDI TARAGHI JAH
CFO | CBO
Business Developer and Financing Management
