Biology subjects

Wu, J. J.

Publications and source records attributed to Wu, J. J..

8 recordsLinked to original sources

bioRxiv2026

HSC70 prevents TDP-43 nuclear puncta formation and toxicity in a novel nuclear puncta cell model for ALS

Amyotrophic lateral sclerosis (ALS) is categorized by TDP-43 proteinopathy, however, the nuclear pathological events remain poorly defined. While cytoplasmic TDP-43 inclusions dominate the late disease stages, accumulating evidence indicates that nuclear TDP-43 assemblies arise earlier and impair RNA splicing. Here, we characterized a single RRM-proximal TDP-43 variant, G148V, designed to disrupt nucleic-acid engagement without altering canonical RNA-binding residues. Structural and biophysical analyses revealed conformational changes and loss of DNA/RNA binding. In mammalian cells, TDP-43 G148V robustly formed nuclear puncta with high penetrance, exhibiting solid-like properties, pathological phosphorylation, splicing dysfunction, and toxicity. Furthermore, we identified molecular chaperone HSC70 as an important regulator of the nuclear puncta assembly. HSC70 redistributed into G148V nuclear puncta to modulate their material state, whereas HSC70 depletion significantly promoted puncta solidification, increased insoluble TDP-43 accumulation, and enhanced cytotoxicity. Disease-associated K181E and K263E mutants also formed nuclear puncta and induced HSC70 nuclear redistribution. These findings establish G148V as a model of early nuclear TDP-43 pathology and highlight HSC70-mediated regulation as a key factor of TDP-43 nuclear assembly. HighlightsO_LIA single TDP-43 mutation, G148V, in RRM1 domain robustly induces nuclear puncta without exogenous stress. C_LIO_LIG148V disrupts nucleic-acid binding, driving solid-like nuclear assemblies with hyperphosphorylation. C_LIO_LINuclear G148V puncta impair splicing regulation and reduce cell viability, recapitulating early ALS pathology. C_LIO_LIThe molecular chaperone HSC70 modulates puncta material states and mitigates G148V-associated cytotoxicity. C_LI Graphical abstrac O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=107 SRC="FIGDIR/small/739729v1_ufig1.gif" ALT="Figure 1"> View larger version (47K): org.highwire.dtl.DTLVardef@d019c8org.highwire.dtl.DTLVardef@4ca632org.highwire.dtl.DTLVardef@331fd9org.highwire.dtl.DTLVardef@6fe8e4_HPS_FORMAT_FIGEXP M_FIG C_FIG eTOC blurbA structure-guided TDP-43 G148V mutation reveals how loss of nucleic-acid engagement promotes early nuclear condensation, splicing dysfunction, and toxicity, while uncovering a protective role for HSC70 in regulating condensate properties during ALS pathogenesis.

cell biology↗

bioRxiv2023

Synergistic efficacy of tigecycline combined with apramycin against tet(X)-harboring Acinetobacter spp.

The emergence of the wide variety of novel tigecycline resistance tet(X) variants including tet(X3), tet(X4), tet(X5) and tet(X6) has posed a significant challenge to the clinical treatment of multidrug-resistant bacterial infections and represents a serious threat to global public health. The purpose of this study was to evaluate the synergism of tigecycline combined with other antibiotics as a means of overcoming tet(X)-mediated resistance in Acinetobacter spp. We found that the combinations of tigecycline with apramycin or amikacin exhibited synergistic activity against tet(X)-harboring Acinetobacter spp. with FICI values of 0.088 and 0.625, respectively. The MICTGC decreased >5-fold decrease in the presence of subinhibitory levels of apramycin. This combination was shown to be a therapeutically effective synergism using both in vitro and in vivo (mouse thigh infection model) assays and delayed the increase of MIC values over time. This study highlights the synergism of tigecycline in combination with apramycin which offers a viable therapeutic alternative for infections caused by tet(X)-harboring Acinetobacter.

pharmacology and toxicology↗

bioRxiv2023

Carbon Sequestration in Soils below Seaweed Farms

The hypothesis that seaweed farming contributes to carbon burial below the farms was tested by quantifying burial rates in 20 seaweed farms distributed globally, ranging from 2 to 300 years in operation and from 1 ha to 15,000 ha in size. This involved combining analyses of organic carbon density with sediment accumulation rate in sediments below seaweed farms relative to reference sediments beyond the farm and/or prior to the farm operation. One in every four farms sampled was set over environments that export, rather than retain materials. For the farms that were placed over depositional environments, where sediment accumulation could be quantified, the thickness of sediment layers and stocks of carbon accumulated below the farms increased with farm age, reaching 140 ton C ha-1 for the oldest farm, and tended to exceed those in reference sediments beyond the farm and/or prior to the operation of the farms. Organic carbon burial rates in the farm sediments averaged ({+/-} SE) 1.87 {+/-} 0.73 ton CO2 equivalent (CO2-eq) ha-1 year-1 (median 0.83, range 0.10 - 8.99 ton CO2-eq ha-1 year-1), twice the average ({+/-} SE) burial rate in reference sediments (0.90 {+/-} 0.27, median 0.64, range 0.10-3.00 ton CO2-eq ha-1 year-1), so that the excess organic carbon burial attributable to the seaweed farms averaged 1.06 {+/-} 0.74 ton CO2-eq ha-1 year-1 (median 0.09, range -0.13-8.10 ton CO2-eq ha-1 year-1). This first direct quantification of carbon burial in sediments below seaweed farms confirms that, when placed over depositional environments, seaweed farming tend to sequester carbon in the underlying sediments, but do so at widely variable rates, increasing with farm yield.

ecology↗

bioRxiv2022

AGS3 antagonizes LGN to balance oriented cell divisions and cell fate choices in mammalian epidermis

Oriented cell divisions balance self-renewal and differentiation in stratified epithelia such as the skin epidermis. During peak epidermal stratification, the distribution of division angles among basal keratinocyte progenitors is bimodal, with planar and perpendicular divisions driving symmetric and asymmetric daughter cell fates, respectively. An apically-polarized, evolutionarily-conserved spindle orientation complex that includes the scaffolding protein LGN/Pins/Gpsm2 plays a central role in promoting perpendicular divisions and stratification, but little is known about the molecular regulation of planar divisions. Here, we demonstrate that the LGN paralog, AGS3/Gpsm1, is a novel negative regulator of LGN, and inhibits perpendicular divisions. Static and ex vivo live imaging reveal that AGS3 overexpression displaces LGN from the apical cortex and increases planar orientations, while AGS3 loss prolongs cortical LGN localization and leads to a perpendicular orientation bias. Genetic epistasis experiments in double mutants confirm that AGS3 operates through LGN. Finally, clonal lineage tracing shows that LGN and AGS3 promote asymmetric and symmetric fates, respectively, while also influencing differentiation through delamination. Collectively, these studies shed new light into how spindle orientation influences epidermal stratification.

developmental biology↗

bioRxiv2022

Neuronal activity regulates Matrin 3 levels and function in a calcium-dependent manner through calpain cleavage and calmodulin binding

RNA-binding protein (RBP) dysfunction is a fundamental hallmark of amyotrophic lateral sclerosis (ALS) and related neuromuscular disorders. Abnormal neuronal excitability is also a conserved feature in ALS patients and disease models, yet little is known about how activity-dependent processes regulate RBP levels and functions. Mutations in the gene encoding the RBP Matrin 3 (MATR3) cause familial disease, and MATR3 pathology has also been observed in sporadic ALS, suggesting a key role for MATR3 in disease pathogenesis. Here, we show that glutamatergic activity drives MATR3 degradation in a NMDAR-, Ca2+-, and calpain-dependent mechanism. The most common pathogenic MATR3 mutation renders it resistant to calpain degradation, suggesting a link between activity-dependent MATR3 regulation and disease. We also demonstrate that Ca2+ regulates MATR3 through a non-degradative process involving the binding of Ca2+/calmodulin (CaM) to MATR3 and inhibition of its RNA-binding ability. These findings indicate that neuronal activity impacts both the abundance and function of MATR3, and provide a foundation for further study of Ca2+-coupled regulation of RBPs implicated in ALS and related neurological diseases.

neuroscience↗

bioRxiv2022

A mosaic-type trimeric RBD-based COVID-19 vaccine candidate induces potent neutralization against Omicron and other SARS-CoV-2 variants

Large-scale populations in the world have been vaccinated with COVID-19 vaccines, however, breakthrough infections of SARS-CoV-2 are still growing rapidly due to the emergence of immune-evasive variants, especially Omicron. It is urgent to develop effective broad-spectrum vaccines to better control the pandemic of these variants. Here, we present a mosaic-type trimeric form of spike receptor-binding domain (mos-tri-RBD) as a broad-spectrum vaccine candidate, which carries the key mutations from Omicron and other circulating variants. Tests in rats showed that the designed mos-tri-RBD, whether used alone or as a booster shot, elicited potent cross-neutralizing antibodies against not only Omicron but also other immune-evasive variants. Neutralizing antibody titers induced by mos-tri-RBD were substantially higher than those elicited by homo-tri-RBD (containing homologous RBDs from prototype strain) or the inactivated vaccine BBIBP-CorV. Our study indicates that mos-tri-RBD is highly immunogenic, which may serve as a broad-spectrum vaccine candidate in combating SARS-CoV-2 variants including Omicron.

immunology↗

bioRxiv2021

Structure and computation-guided design of a mutation-integrated trimeric RBD candidate vaccine with broad neutralization against SARS-CoV-2

The spike (S) protein receptor-binding domain (RBD) of SARS-CoV-2 is an attractive target for COVID-19 vaccine developments, which naturally exists in a trimeric form. Here, guided by structural and computational analyses, we present a mutation-integrated trimeric form of RBD (mutI tri-RBD) as a broadly protective vaccine candidate, in which three RBDs were individually grafted from three different circulating SARS-CoV-2 strains including the prototype, Beta (B.1.351) and Kappa (B.1.617). The three RBDs were then connected end-to-end and co-assembled to possibly mimic the native trimeric arrangements in the natural S protein trimer. The recombinant expression of the mutI tri-RBD, as well as the homo-tri-RBD where the three RBDs were all truncated from the prototype strain, by mammalian cell exhibited correct folding, strong bio-activities, and high stability. The immunization of both the mutI tri-RBD and homo-tri-RBD plus aluminum adjuvant induced high levels of specific IgG and neutralizing antibodies against the SARS-CoV-2 prototype strain in mice. Notably, regarding to the "immune-escape" Beta (B.1.351) variant, mutI tri-RBD elicited significantly higher neutralizing antibody titers than homo-tri-RBD. Furthermore, due to harboring the immune-resistant mutations as well as the evolutionarily convergent hotspots, the designed mutI tri-RBD also induced strong broadly neutralizing activities against various SARS-CoV-2 variants, especially the variants partially resistant to homo-tri-RBD. Homo-tri-RBD has been approved by the China National Medical Products Administration to enter clinical trial (No. NCT04869592), and the superior broad neutralization performances against SARS-CoV-2 support the mutI tri-RBD as a more promising vaccine candidate for further clinical developments.

immunology↗

bioRxiv2020

Scalable production of tissue-like vascularised liver organoids from human PSCs.

A lack of physiological parity between 2D cell culture and in vivo, has paved the way towards more organotypic models. Organoids exist for a number of tissues, including the liver. However, current approaches to generate hepatic organoids suffer drawbacks, including a reliance on extracellular matrices (ECM), the requirement to pattern in 2D culture, costly growth factors and a lack of cellular diversity, structure and organisation. Current hepatic organoid models are generally simplistic, composed of hepatocytes or cholangiocytes, which renders them less physiologically relevant when compared to native tissue. Here we aim to address these drawbacks. To address this, we have developed an approach that does not require 2D patterning, is ECM independent combined with small molecules to mimic embryonic liver development that produces massive quantities of liver like organoids. Using single-cell RNA sequencing and immunofluorescence we demonstrate a liver-like cellular repertoire, a higher order cellular complexity, presenting with vascular luminal structures, innervation and a population of resident macrophage - the Kupffer cells. The organoids exhibit key liver functions including drug metabolism, serum protein production, coagulation factor production, bilirubin uptake and urea synthesis. The organoids can be transplanted and maintained in mice producing human albumin long term. The organoids exhibit a complex cellular repertoire reflective of the organ, have de novo vascularization and innervation, enhanced function and maturity. This is a pre-requisite for a myriad of applications from cellular therapy, tissue engineering, drug toxicity assessment, disease modeling, to basic developmental biology.

cell biology↗