Biology subjects

Liu, M.-L.

Publications and source records attributed to Liu, M.-L..

7 recordsLinked to original sources

bioRxiv2024

Distinct Effects of Aducanumab and Lecanemab on Intraneuronal Endogenous Aβ42 and Phosphorylated Tau in Alzheimer's Disease Treatment

In the treatment of Alzheimers Disease (AD), two FDA-approved monoclonal antibodies, Aducanumab (Adu) and Lecanemab (LCN), exhibit significant differences in clinical benefits. By utilizing human-induced basal forebrain cholinergic neurons (BFCNs) derived from AD patient skin fibroblasts, we successfully recapitulated the natural endogenous neuropathologies of A{beta}42 and Tau within just 21 days and revealed distinct intraneuronal effects of Adu and LCN. Both antibodies are internalized into BFCNs and localize with cytosolic A{beta}42. However, LCN, selectively targeting A{beta}42 oligomers and protofibrils, triggers TRIM21 pathway and significantly enhances autolysosome- and proteasome-mediated A{beta}42 clearance, thereby leading to a marked reduction in phosphorylated Tau181 (pTau181) pathology. In contrast, the fibrillized A{beta}42-selective Adu shows considerably weaker effects. This study not only reveals the unique intraneuronal actions of Adu and LCN but also provides a reliable and accessible human neuronal model for evaluating potential AD therapeutics, emphasizing the importance of intraneuronal pathology in the treatment of AD.

neuroscience↗

bioRxiv2023

Neutrophil extracellular traps drive lupus flares with acute skin and kidney inflammation triggered by ultraviolet irradiation

Neutrophil extracellular traps (NETs) are major pathogenic effectors in chronic systemic lupus erythematosus (SLE) pathogenesis, but how they mediate acute, UVB-triggered skin inflammation and subsequent systemic injury remains poorly defined. Using UVB-irradiated lupus-prone mice, we identified an acute NETosis-driven skin-kidney inflammatory axis linking photosensitivity to renal inflammation. UVB induced concurrent skin and kidney inflammation with neutrophil infiltration, NETosis, and release of NET-associated effector cytokines/complement C3 and proteinuria. Mechanistically, PKC-dependent nuclear envelope rupture licensed NETosis, whereas Pkc deletion markedly suppressed NET formation and inflammation in both organs. Interestingly, only a subset of skin-infiltrating neutrophils underwent local NETosis. Spatiotemporal photoconversion tracking revealed that surviving, CXCR4-expressing neutrophils disseminated from UVB-irradiated skin to kidneys, where they underwent secondary NETosis, delivering cytokines/C3 to drive renal inflammation. Genetic or pharmacological CXCR4 inhibition blocked this dissemination, attenuating renal inflammation and proteinuria. These findings identify an acute NETosis-driven skin-kidney axis, highlighting PKC-dependent NETosis and CXCR4-mediated neutrophil dissemination as therapeutic targets in photosensitive lupus.

pathology↗

bioRxiv2023

Chemical screens in aging-relevant human motor neurons identify MAP4Ks as therapeutic targets for amyotrophic lateral sclerosis

Effective therapeutics is much needed for amyotrophic lateral sclerosis (ALS), an adult-onset neurodegenerative disease mainly affecting motor neurons. By screening chemical compounds in human patient-derived and aging-relevant motor neurons, we identify a neuroprotective compound and show that MAP4Ks may serve as therapeutic targets for treating ALS. The lead compound broadly improves survival and function of motor neurons directly converted from human ALS patients. Mechanistically, it works as an inhibitor of MAP4Ks, regulates the MAP4Ks-HDAC6-TUBA4A-RANGAP1 pathway, and normalizes subcellular distribution of RANGAP1 and TDP-43. Finally, in an ALS mouse model we show that inhibiting MAP4Ks preserves motor neurons and significantly extends animal lifespan.

neuroscience↗

bioRxiv2023

A simple, flexible and high-efficiency western blot analysis for age-related human induced neurons

High-throughput western blot (WB) analysis of small and precious samples, such as various age-related subtype-specific human induced neurons (hiNs), confers the ability to obtain more consistent, comparable, and informative data from materials with extremely limited availability. In this study, p-toluenesulphonic acid (PTSA), an odorless tissue fixative, was used to inactivate HRP for developing a high-throughput WB method. PTSA-treated blots showed fast and efficient inactivation of HRP without detectable protein loss and epitope damage. With a brief PTSA-treatment before every next probing, 10 proteins of dopaminergic hiNs could be sequentially, sensitively, and specifically detected in a blot. These WB data proved the age-associated and neuron-specific features of hiNs and further revealed a sharp reduction of two Parkinsons disease-associated proteins, UCHL1 and GAP43, in the normal aging dopaminergic neurons. Together, this study developed a unique and high-efficiency WB analysis and pinpointed its special value for capturing robust useful data from limited, precious samples. GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=143 SRC="FIGDIR/small/526150v2_ufig1.gif" ALT="Figure 1"> View larger version (25K): org.highwire.dtl.DTLVardef@18fcd9dorg.highwire.dtl.DTLVardef@42426org.highwire.dtl.DTLVardef@1e13accorg.highwire.dtl.DTLVardef@1db2f39_HPS_FORMAT_FIGEXP M_FIG C_FIG HIGHLIGHTS{checkmark} P-toluenesulphonic acid (PTSA) quickly and fully deactivated HRP on immunoblots. {checkmark}PTSA was an odorless, non-volatile, low cost, and user-friendly HRP inactivator. {checkmark}PTSA allowed high-efficiency WB analysis to save small precious samples and time. {checkmark}10 proteins were detected in a single blot of age-relevant human induced neurons. {checkmark}UCHL1 and GAP43 sharp decline occurred in aging human induced dopaminergic neurons.

biochemistry↗

bioRxiv2021

Deficiency of Rho Kinase 1 (ROCK1) attenuates neutrophil NETosis and ameliorates UVB-induced skin inflammation

ObjectiveUltraviolet B (UVB) is an important trigger of skin inflammation and lupus with leukocyte recruitment to inflamed skin. We recently reported the involvement of neutrophil NETosis in UVB-induced skin inflammation, and that NETotic nuclear envelope rupture is driven by PKC-mediated nuclear lamin B disassembly. To address the role of Actin cytoskeleton in NETosis, we investigated the effects of Rho kinase (ROCK) and its downstream actomyosin cytoskeletal networks on PKC nuclear translocation and NET formation, as well as their involvement in UVB-induced skin inflammation. MethodsWe studied the dynamic changes of ROCK and actomyosin cytoskeletal networks during NETosis induction and their involvement in PKC nuclear translocation. Using mice with hematopoietic-specific ROCK1 deficiency, we investigated the effects of ROCK1 deficiency on NETosis, and its involvement in UVB-induced skin inflammation. ResultsOur time course studies demonstrated the dynamic changes of actin polymerization and ROCK activation, support the role of actin cytoskeleton in nuclear translocation of cytosolic PKC in early stage of NETosis induction. Inhibition of actin polymerization or key molecules of the ROCK/MLCK/myosin pathway decreased PKC nuclear translocation and NET formation. Genetic deficiency of ROCK1, inhibited NETosis ex vivo and in vivo, decreased extracellular display of NET-associated IL-17A, TNF, IFN{gamma}, and IFN in inflamed skin, which were correlated with the ameliorated skin inflammation in UVB-irradiated mice with hematopoietic-specific ROCK1 deficiency. ConclusionsROCK regulated NETosis through modulation of PKC nuclear translocation via actomyosin cytoskeletal networks in neutrophils. ROCK1 deficiency ameliorated UVB- induced skin inflammation by attenuation of NETosis and NET-associated cytokines.

pathology↗

bioRxiv2020

Disease modeling with human neurons reveals LMNB1 dysregulation underlying DYT1 dystonia

DYT1 dystonia is a hereditary neurological disease caused by a heterozygous mutation in torsin A (TOR1A). While animal models provide insights into disease mechanisms, significant species-dependent differences exist since mice with the identical heterozygous mutation fail to show pathology. Here, we model DYT1 by using human patient-derived motor neurons. These neurons with the heterozygous TOR1A mutation show markedly thickened nuclear lamina, disrupted nuclear morphology, and impaired nucleocytoplasmic transport, whereas they lack the perinuclear "blebs" that are often observed in animal models. Importantly, we further uncover that the nuclear lamina protein LMNB1 is specifically dysregulated in expression and subcellular localization. LMNB1 downregulation can largely ameliorate all the cellular defects in DYT1 motor neurons. These results reveal the value of disease modeling with human neurons and provide novel molecular mechanisms underlying DYT1 dystonia and potentially other neurological diseases with impaired nucleocytoplasmic transport.

neuroscience↗

bioRxiv2019

Nuclear lamin B is crucial to the nuclear envelope integrity and extracellular trap release in neutrophils

Its not clear how nuclear envelope (NE) is ruptured for chromatin externalization during NETosis. The membrane rupture during neutrophil NET release was described as a membrane lysis process, this notion, however, has been questioned. Here, we found that lamin B, the structural NE component, was involved in NETosis. Unexpectedly, lamin B was not fragmented by destructive proteolysis, but rather disassembled into its intact full-length molecule, in NETotic cells with ruptured NE. In the mechanistic study, our experiments demonstrated that cytosolic PKC translocated to the nucleus, where it serves as a NETotic lamin kinase to induce lamin B phosphorylation, following by lamina disassembly and NE rupture. To determine causality, we found that decreasing lamin B phosphorylation, by PKC inhibition or genetic deletion, or mutation at the PKC consensus phosphorylation sites of lamin B, attenuated extracellular trap formation. Importantly, strengthening NE by lamin B overexpression attenuated neutrophil NETosis in vivo and alleviated exhibition of NET-associated inflammatory cytokines in UVB irradiated skin of lamin B transgenic mice. These findings advance our understanding of NETosis process and elucidate a cellular mechanism that PKC-mediated lamin B phosphorylation drives nuclear envelope rupture for NET release in neutrophils.\n\nGraphical Abstract\n\nO_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=140 SRC=\"FIGDIR/small/647529v1_ufig1.gif\" ALT=\"Figure 1\">\nView larger version (49K):\norg.highwire.dtl.DTLVardef@7bd231org.highwire.dtl.DTLVardef@124bf6dorg.highwire.dtl.DTLVardef@19396ecorg.highwire.dtl.DTLVardef@9989cb_HPS_FORMAT_FIGEXP M_FIG C_FIG

immunology↗