Neurosciences, Neurodegenerative diseases, Alzheimer's didease

Funding: Alzheimer's Association Fellowship Grant; 2017-2020

April 14, 2016	Postdoctoral Fellow & Research Associate Award for Excellence in Research 2016. Cleveland Clinic Lerner Research Institute, Cleveland, Ohio 44195, USA.
May 21, 2015	The Post-doctoral Neurosciences Award. Neurological Institute, Cleveland Clinic Foundation, Cleveland, Ohio 44195, USA.
2007-2011	Research Assistantship. Chosun University, Gwangju, Republic of Korea.
2007-2009	Foreign Students Scholarship. Chosun University, Gwangju, Republic of Korea.
2006	Effective Performance Award. Nestle Bangladesh Ltd., Dhaka, Bangladesh.
2005	Best Achievement Award. Nestle Bangladesh Ltd., Dhaka, Bangladesh.
2002	Talentful Stipend. Rajshahi University, Rajshahi, Bangladesh.
2000	Gold Medal Award. Shaheed Ziaur Rahman Hall, Rajshahi University, Bangladesh.

Cleveland Clinic Lerner Research Institute, Cleveland Ohio 44195 USA/ Case Western Researve University, Cleveland, Ohio
Research Associate / Adjunct Instructor

My research focuses on pathological and therapeutic aspects of Alzheimer’s disease (AD), the most common form of aging associated dementia. While, the actual causes of the onset of AD is not clear yet, the formation of b-amyloid (Ab) peptide composed neuritic plaque in the brain is considered a major pathological feature of AD . Although, Abplaque is also found in normal aging brain but as defused form, a neuritic plaque in AD brain often constitute with an Ab core and it surrounding dystrophic neurites (DNs), activated microglia and reactive astrocytes (Figure 1a). Hence, formation of DNs is a distinguishing feature in AD brain. DNs refer to swollen neuritic processes and their presence correlates with synaptic impairments. In AD postmortem brains, DNs are morphologically recognized by immunohistochemical staining with antibodies specific to ubiquitin, neurofilament, phosphorylated tau, and amyloid precursor protein (APP). Previous study from our lab has shown that antibodies against reticulon 3 (RTN3), a tubular endoplasmic reticulum (ER) shaping protein, label an abundant population of DNs in AD brains, when compared to those previously-reported markers (Figure 1b). Due to their abundancy, these RTN3 antibody detected DNs were designated as RTN3 immunoreactive DNs or RIDNs. Formation of RIDNs is also an autonomous process in aging mice brain, specifically at hippocampus, which was accelerated by over expressing RTN3 in mice brain (Tg-RTN3); the formation of RIDNs in Tg-RTN3 mice brain hippocampus correlates with the synaptic dysfunction of those mice. The prime focuses of my long-term studies are understanding the mechanism of the formation of DNs and developing the therapeutics for this pathological constitution in AD brain. To this endeavor, my following novel findings  has enlighten the mechanistic detail on the formation of DNs in aging and AD brains.

1. Dysfunctional tubular ER constitutes RIDNs in aging and AD brain [Molecular Psychiatry, 2016]​​

2. DNs in AD brain constitute with three sequential layers [Molecular Psychiatry, 2019]

 3. RTN3 deficiency enhances amyloid deposition [Journal of Neuroscince, 2014, Reviews in the Neurosciences, 2017]

Figure 1. b-amyloid induced DNs formation in AD brain.a)DAB staining of AD postmortem brain showing a typical neuritic plaque that constitute with an b-amyloid deposited core and its surrounding DNs, activated microglia and reactive astrocytes (Dickson et al., 1999). b)Immuno-confocal image of AD human postmortem brain showing that C- (R458) and N- terminal (R459) specific antibodies to RTN3 stains majority of plaque surrounding DNs compare to those stained with phosphor-tau (p-tau), ubiquitin and neurofilaments (NF) (Hu et al.,2007). c)Tubular ER accumulation in DNs: Tubular ER is part of smooth ER, normally distributed along the axon (A); tubular ER in dendrites and soma are not illustrated. Increased RTN3 expression and its aggregation appears to induce abnormal distribution of tubular ER, especially at the axonal terminus, where synaptic vesicles were also visible (B). Increased tubular ER clustering appears sequential and is correlated with visible increases in smaller-sized mitochondria in the affected region (C). The model is developed observation from the immuno-confocal and EM studies on younger and aged Tg-RTN3 CA1 region, AD biopsy sample and AD mice brain, where RIDNs are abundantly developed and tubular ER is often found within an inclusion body with either degenerated or deficient mitochondria. d)In AD brain, DNs are constitute with numerous proteins and organelle those abnormally accumulate due to impairment of several essential cellular processes such as autophagy, tubular ER distribution, and ubiquitin proteasome system. The gradual deposition of those proteins, organelle and vesicles appeared to be constitutes a sequential layer of DNs. Abnormal accumulation of ATG9A, an early autophagy protein, in DNs is an initial event during amyloid plaque formation that build first layer of DNs, which followed by RTN3 mediated ER tubule clustered RIDNs, and finally by a third layer of defective autophagy vesicles. In immuno-confocal study, the defective autophagy intermediates could be detected using autophagosomes or autolysosomes specific antibodies such as LC3, RAB7, LAMP1, LAMP2 and Cathepsin D. Dysfunction of ubiquitin proteasome system appear to be a late event during plaque growth and the ubiquitin is a component of peripheral layer of DNs. e)A 3D reconstructed model of a plaque showing the distribution of different population DNs in

1. Md Golam Sharoar, Xiangyou Hu, Xin-Ming Ma, Xiongwei Zhuand Riqiang Yan. Sequential formation of different layers of dystrophic neurites in Alzheimer’s disease brains. Molecular Psychiatry 2019 (in press).

2. Limited activation of the intrinsic apoptotic pathway plays a main role in amyloid-β-induced apoptosis without eliciting the activation of the extrinsic apoptotic pathway.

Islam MI, Sharoar MG, Ryu EK, Park IS. Int J Mol Med. 2017 Dec;40(6):1971-1982. doi: 10.3892/ijmm.2017.3193. Epub 2017 Oct 16.PMID:29039468

3. Effects of altered RTN3 expression on BACE1 activity and Alzheimer's neuritic plaques. Sharoar MG, Yan R. Rev Neurosci. 2017 Feb 1;28(2):145-154. doi: 10.1515/revneuro-2016-0054. Review. PMID:27883331

4. Dysfunctional tubular endoplasmic reticulum constitutes a pathological feature of Alzheimer's disease. Sharoar MG, Shi Q, Ge Y, He W, Hu X, Perry G, Zhu X, Yan R. Mol Psychiatry. 2016 Sep;21(9):1263-71. doi: 10.1038/mp.2015.181. Epub 2015 Dec 1. PMID: 26619807

5. Impact of RTN3 deficiency on expression of BACE1 and amyloid deposition. Shi Q, Ge Y, Sharoar MG, He W, Xiang R, Zhang Z, Hu X, Yan R. J Neurosci. 2014 Oct 15;34(42):13954-62. doi: 10.1523/JNEUROSCI.1588-14.2014. PMID:25319692

6. Amyloid β binds procaspase-9 to inhibit assembly of Apaf-1 apoptosome and intrinsic apoptosis pathway. Sharoar MG, Islam MI, Shahnawaz M, Shin SY, Park IS. Biochim Biophys Acta. 2014 Apr;1843(4):685-93. doi: 10.1016/j.bbamcr.2014.01.008. Epub 2014 Jan 12. PMID: 24424093

7. The inhibitory effects of Escherichia coli maltose binding protein on β-amyloid aggregation and cytotoxicity. Sharoar MG, Shahnawaz M, Islam MI, Ramasamy VS, Shin SY, Park IS. Arch Biochem Biophys. 2013 Oct 1;538(1):41-8. doi: 10.1016/j.abb.2013.08.004. Epub 2013 Aug 13. PMID: 23948569

8. Wild-type, Flemish, and Dutch amyloid-β exhibit different cytotoxicities depending on Aβ40 to Aβ42 interaction time and concentration ratio. Shahnawaz M, Sharoar MG, Shin SY, Park IS. J Pept Sci. 2013 Sep;19(9):545-53. doi: 10.1002/psc.2531. Epub 2013 Jul 13. PMID: 23853087

9. Keampferol-3-O-rhamnoside abrogates amyloid beta toxicity by modulating monomers and remodeling oligomers and fibrils to non-toxic aggregates. Sharoar MG, Thapa A, Shahnawaz M, Ramasamy VS, Woo ER, Shin SY, Park IS. J Biomed Sci. 2012 Dec 21;19:104. doi: 10.1186/1423-0127-19-104. PMID: 23259691

10. Biflavonoids are superior to monoflavonoids in inhibiting amyloid-β toxicity and fibrillogenesis via accumulation of nontoxic oligomer-like structures. Thapa A, Woo ER, Chi EY, Sharoar MG, Jin HG, Shin SY, Park IS. Biochemistry. 2011 Apr 5;50(13):2445-55. doi: 10.1021/bi101731d. Epub 2011 Mar 15. PMID: 21322641

11. Purification of catalytically active caspase-12 and its biochemical characterization. Lee HJ, Lee SH, Park SH, Sharoar MG, Shin SY, Lee JS, Cho B, Park IS. Arch Biochem Biophys. 2010 Oct 1;502(1):68-73. doi: 10.1016/j.abb.2010.07.013. Epub 2010 Jul 18. PMID: 20646990

12. Purification of inclusion body-forming peptides and proteins in soluble form by fusion to Escherichia coli thermostable proteins. Thapa A, Shahnawaz M, Karki P, Raj Dahal G, Sharoar MG, Yub Shin S, Sup Lee J, Cho B, Park IS. Biotechniques. 2008 May;44(6):787-96. doi: 10.2144/000112728. PMID: 18476832

 

Contribution to newsletter article

1. Research is Love. Iris Nira Smith, Amina Abbadi, Kelsey Bohn, MG Sharoar, Madhav Sankunny, Angél Reyes-Rodriguez, Alice Valentin-Torres, Aimalie Hardaway, Gaoyuan Liu and Rafael Luna. National Research Mentoring Network (NRMN) Newsletter, October 2017. https://nrmnet.net/research-is-love/

2. Identifying Effective Targets for Alzheimer’s Disease Treatment. Editorial Article on interview by Lynsey Forsyth, Associate Editor of Select Science. December 2016. https://www.selectscience.net/editorial-articles/identifying-effective-targets-for-alzheimers-disease-treatment/?artID=42659