Linyi Chen

Various vaccines have been developed in response to the SARS-CoV-2 pandemic, and the safety of vaccines has become an important issue. COVID-19 vaccine-related central nervous system inflammatory demyelinating diseases (CNS IDDs) have been reported recently. We present one case of AstraZeneca vaccine-related myelin oligodendrocyte glycoprotein (MOG) antibody-associated disease and a literature review of another 78 patients published from January 2020 to October 2022. Patients were divided into three vaccine types (viral vector, mRNA, and inactivated vaccines) for further analyses. Among 79 patients with COVID-19 vaccine-related CNS IDDs, 49 (62%) cases received viral vector vaccines, 20 (25.3%) received mRNA vaccines, and 10 (12.7%) received inactivated vaccines. Twenty-seven cases (34.2%) were confirmed with autoantibodies, including fifteen patients (19%) with anti-MOG, eleven (13.9%) with anti-aquaporin 4 (AQP4), and one (1.3%) with both antibodies. Significantly, more males developed CNS IDDs post viral vector vaccines compared to mRNA and inactivated vaccines. Patients receiving mRNA vaccines were older than those receiving other types. Furthermore, mRNA and inactivated vaccines correlated more with anti-AQP4 antibodies, while viral vector vaccines showed higher MOG positivity. This research suggests potential associations between COVID-19 vaccine-related CNS IDDs and gender, age, and autoantibodies, contingent on vaccine types. Protein sequence analysis implies similarities between the S protein and AQP4/MOG. Further studies may elucidate the mechanisms of CNS IDDs, aiding vaccine selection for specific types.

Ganglioside GAA-7 exhibits higher neurite outgrowth than ganglioside GM1a and most echinodermatous gangliosides (EGs) when tested on neuron-like rat adrenal pheochromocytoma (PC12) cells in the presence of nerve growth factor (NGF). The unique structure of GAA-7 glycan, containing an uncommon sialic acid (8-O-methyl-N-glycolylneuraminic acid) and sialic acid-α-2,3-GalNAc linkage, makes it challenging to synthesize. We recently developed a streamlined method to chemoenzymatically synthesize GAA-7 glycan and employed this modular strategy to efficiently prepare a library of GAA-7 glycan analogues incorporating N-modified or 8-methoxyl sialic acids. Most of these synthetic glycans exhibited moderate efficacy in promoting neuronal differentiation of PC12 cells. Among them, the analogue containing common sialic acid shows greater potential than the GAA-7 glycan itself. This result reveals that methoxy modification is not essential for neurite outgrowth. Consequently, the readily available analogue presents a promising model for further biological investigations.

Background: Patients suffered from severe traumatic brain injury (TBI) have twice the risk of developing into neurodegenerative diseases later in their life. Thus, early intervention is needed not only to treat TBI but also to reduce neurodegenerative diseases in the future. Physiological functions of neurons highly depend on mitochondria. Thus, when mitochondrial integrity is compromised by injury, neurons would initiate a cascade of events to maintain homeostasis of mitochondria. However, what protein senses mitochondrial dysfunction and how mitochondrial homeostasis is maintained during regeneration remains unclear. Results: We found that TBI-increased transcription of a mitochondrial protein, phosphoglycerate mutase 5 (PGAM5), during acute phase was via topological remodeling of a novel enhancer-promoter interaction. This up-regulated PGAM5 correlated with mitophagy, whereas presenilins-associated rhomboid-like protein (PARL)-dependent PGAM5 cleavage at a later stage of TBI enhanced mitochondrial transcription factor A (TFAM) expression and mitochondrial mass. To test whether PGAM5 cleavage and TFAM expression were sufficient for functional recovery, mitochondrial oxidative phosphorylation uncoupler carbonyl cyanide 4-(trifluoromethoxy) phenylhydrazone (FCCP) was used to uncouple electron transport chain and reduce mitochondrial function. As a result, FCCP triggered PGAM5 cleavage, TFAM expression and recovery of motor function deficits of CCI mice. Conclusions: Findings from this study implicate that PGAM5 may act as a mitochondrial sensor for brain injury to activate its own transcription at acute phase, serving to remove damaged mitochondria through mitophagy. Subsequently, PGAM5 is cleaved by PARL, and TFAM expression is increased for mitochondrial biogenesis at a later stage after TBI. Taken together, this study concludes that timely regulation of PGAM5 expression and its own cleavage are required for neurite re-growth and functional recovery.

To better implement mesenchymal stem cell (MSC)-based therapy toward cartilage diseases, a more efficient and less off-target chondrogenesis protocol is needed. Here, we present a protocol to induce human MSC chondrogenesis via Wnt antagonism. We describe steps for pellet formation, Wnt antagonism-based chondrogenic induction, and refreshing the differentiation medium. We detail procedures for characterizing MSC chondrogenesis. By using Wnt antagonism instead of conventional transforming growth factor β-based induction, this protocol avoids the potential for induction of chondrocyte hypertrophy/osteogenesis or other lineages. For complete details on the use and execution of this protocol, please refer to Hsieh et al. (2023). ¹