TDP-43 proteinopathies encompass frontotemporal lobar degeneration with TDP-43 pathology (FTLD-TDP), amyotrophic lateral sclerosis (ALS-TDP), and limbic predominant age related TDP-43 encephalopathy neuropathological change (LATE-NC). These proteinopathies exhibit subtype-specific aggregate architectures that may constrain epitope accessibility in situ. We compared a phosphorylation-independent monoclonal antibody targeting a C-terminal epitope (MAb No. 9) with the phospho-specific pSer409/410 antibody to determine whether its signal relates to regional neurodegeneration in a multicenter autopsy cohort spanning FTLD-TDP types A-C, ALS-TDP, and Alzheimer disease neuropathologic change (ADNC) with or without LATE-NC. Immunolabeling with MAb No. 9 detected pathological TDP-43 across all diagnostic groups with enhanced labeling of dystrophic neurites and thread/dot-like pathology in FTLD-TDP types A/B and in ALS-TDP. MAb No. 9 performance was equivalent to p409/410 in FTLD-TDP type C. In ADNC with stage 3 LATE-NC, MAb No. 9 revealed a greater limbic burden and labeled both α type and β type inclusions. Dual label immunofluorescence demonstrated strong spatial overlap with p409/410 but additionally highlighted fine punctate pathology. MAb No. 9 burden in FTLD-TDP type A correlated strongly with cortical neurodegeneration but showed weaker and variable associations, particularly in severely atrophic cortex. These findings indicate that filament architecture governs C-terminal epitope accessibility and that MAb No. 9 may be a complementary tool for subtype refinement, clinicopathologic correlation and translational biomarker development in TDP-43 proteinopathies.
Owing to the existence of the blood-brain barrier (BBB), achieving high-efficacy, tumor-selective delivery of therapeutic agents continues to be a pivotal unmet need in the treatment of glioblastoma. Here, based on the finding that CD93 is exclusively up-regulated on glioma-associated vascular endothelial cells (VECs), small extracellular vesicles (sEVs) were modified with insulin-like growth factor-binding protein 7 (IGFBP7), a natural ligand of CD93, to create a delivery platform that can deliver therapeutic agents to glioma-associated VECs with high efficiency. At markedly reduced intravenous doses, IGFBP7-sEVs efficiently concentrated temozolomide (TMZ) within glioma and elicited pronounced tumor growth inhibition. More strikingly, systemic administration of stimulator of interferon genes (STING) agonist-loaded IGFBP7-sEVs outperformed direct intratumoral injection of free STING agonist: the glioma microenvironment (GME) was extensively remodeled and antigen-presenting capacity of myeloid cells was markedly enhanced. Moreover, endothelial-restricted STING activation attenuated the exhaustion of CD8+ T cells. Consequently, the intensity of the tumor-specific immune response was markedly augmented. Our data suggest that IGFBP7-modified sEVs represent a novel platform that enables highly efficient, glioma VECs-targeted delivery of therapeutics into glioma, and are adaptable to a broad spectrum of agents, especially immunomodulators. It is a novel and effective strategy for treating gliomas.
Targeted gene integration mediated by CRISPR/Cas9 is a promising therapeutic strategy for monogenic autosomal recessive diseases. In this study, we established a novel all-in-one high-capacity adenovirus (HCAd) that can pack both CRISPR/Cas9 and donor DNA into the same vector and tested it on a mouse model of mucopolysaccharidosis type VII (MPS VII) caused by mutations in the β-glucuronidase (GUSB) gene. This system allowed targeted integration of promoterless GUSB in the mouse beta-actin gene (mActb) locus and the co-expression of GUSB with the self-cleaving peptide T2A (T2A) controlled by a strong endogenous mActb promoter. The in vivo results indicated that the serum GUSB level of MPS VII mice treated with a single intraperitoneal injection of the HCAd vector achieved 14
The RNA/DNA-binding protein TDP-43 plays a pivotal role in the ubiquitinated inclusions characteristic of TDP-43 proteinopathies, including most cases of frontotemporal lobar degeneration (FTLD-TDP) and Alzheimer disease (AD). To understand the mechanisms of pathological TDP-43 processing and identify potential biomarkers, we generated novel phosphorylation-independent monoclonal antibodies (MAbs) using bacteria-expressed human full-length recombinant TDP-43. Remarkably, we identified a distinctive MAb, No. 9, targeting an epitope in amino acid (aa) region 311-360 of the C-terminus. This antibody showed preferential reactivity for pathological TDP-43 inclusions, with only mild reactivity for normal nuclear TDP-43. MAb No. 9 revealed more pathology in FTLD-TDP type A and type B brains and in AD brains compared to the commercial p409/410 MAb. Using synthetic phosphorylated peptides, we also obtained MAbs targeting the p409/410 epitope. Interestingly, MAb No. 14 was found to reveal additional pathology in AD compared to the commercial p409/410 MAb, specifically, TDP-43-immunopositive deposits with amyloid plaques in AD brains. These unique immunopositivities observed with MAbs No. 9 and No. 14 are likely attributed to their conformation-dependent binding to TDP-43 inclusions. We expect that this novel set of MAbs will prove valuable as tools for future patient-oriented investigations into TDP-43 proteinopathies.
Macrophage polarization is closely related to inflammation development, yet how macrophages are polarized remains unclear. In our study, the number of M1 macrophages was markedly increased in Fam76b knockout U937 cells vs. wild-type U937 cells, and FAM76B expression was decreased in M1 macrophages induced from different sources of macrophages. Moreover, Fam76b knockout enhanced the mRNA and protein levels of M1 macrophage-associated marker genes. These results suggest that FAM76B inhibits M1 macrophage polarization. We then further explored the mechanism by which FAM76B regulates macrophage polarization. We found that FAM76B can regulate PI3K/Akt/NF-κB pathway-mediated M1 macrophage polarization by stabilizing PIK3CD mRNA. Finally, FAM76B was proven to protect against inflammatory bowel disease (IBD) by inhibiting M1 macrophage polarization through the PI3K/Akt/NF-κB pathway in vivo. In summary, FAM76B regulates M1 macrophage polarization through the PI3K/Akt/NF-κB pathway in vitro and in vivo, which may inform the development of future therapeutic strategies for IBD and other inflammatory diseases.
FAM76B has been reported to be a nuclear speckle-localized protein with unknown function. In this study, FAM76B was first demonstrated to inhibit the NF-κB-mediated inflammatory pathway by affecting the translocation of hnRNPA2B1 in vitro. We further showed that FAM76B suppressed inflammation in vivo using a traumatic brain injury (TBI) mouse model. Lastly, FAM76B was shown to interact with hnRNPA2B1 in human tissues taken from patients with acute, organizing, and chronic TBI, and with different neurodegenerative diseases. The results suggested that FAM76B mediated neuroinflammation via influencing the translocation of hnRNPA2B1 in vivo during TBI repair and neurodegenerative diseases. In summary, we for the first time demonstrated the role of FAM76B in regulating inflammation and further showed that FAM76B could regulate the NF-κB-mediated inflammatory pathway by affecting hnRNPA2B1 translocation, which provides new information for studying the mechanism of inflammation regulation.
FAM76B is nuclear speckle-localized protein with a molecular weight of 39 kDa. The amino sequence of FAM76B protein is highly conserved among species, suggesting that FAM76B has important biological functions. However, the biological function of FAM76B is currently still unclear. To explore the biological function of FAM76B, we firstly used zebrafish as the experimental model to study the distribution and expression level of Fam76b. The results indicated that fam76b is highly expressed in hematopoiesis and immune systems of zebrafish by real-time quantitative PCR, in situ hybridization and Tg(fam76b: eGFP) transgenic zebrafish. Then, the fam76b gene was knocked out by CRISPR/Cas9 in zebrafish and fam76b rescue in fam76b-/- zebrafish was performed using the TOL2 transposable system. fam76b gene knockout zebrafish exhibit reduced thymus, excessive inflammatory response, and increased mortality. FAM76B was further found to be involved in regulating the development of hematopoiesis and immune system, and participate in the process of inflammatory response. Our findings in the study lay the groundwork for elucidating the function of the new molecule Fam76b and provide new insights into the development of zebrafish hematopoietic and immune system.
Traumatic brain injury (TBI) can be progressive and can lead to the development of a long-term complication termed chronic traumatic encephalopathy. The mechanisms underlying the progressive changes are still unknown; however, studies have suggested that microglia-mediated neuroinflammation in response to TBI may play a fundamental role. This study aimed to determine whether progranulin (PGRN), a major modulator of microglial activity, plays a role in the progressive damage following TBI. PGRN-deficient and wild-type mice were subjected to controlled cortical impact and were observed neuropathologically after 3 days, 7 days, and 5 months. Compared to sham and wild-type mice, the PGRN-deficient mice showed overall stronger microgliosis and astrocytosis. The astrocytosis involved broader areas than the microgliosis and was more prominent in the basal ganglia, hippocampus, and internal capsule in PGRN-deficient mice. Ongoing neuronal death was uniquely observed in the hippocampal CA3 region of PGRN-deficient mice at 5 months after TBI, accompanying the regional chronic microgliosis and astrocytosis involving the CA3 commissural pathway. In addition, there was M1 microglial polarization in the pericontusional area with activated TLR4/MyD88/NF-κB signaling; however, the hippocampus showed only mild M1 polarization 7 days after TBI. Lastly, Morris water maze tests showed PGRN-deficient mice had poorer spatial learning and memory 5 months after TBI than wild-type or sham mice. The data indicated the PGRN deficiency caused TBI progression by promoting persistent microgliosis with microglial polarization and astrocytosis, as well as regional pathology in the hippocampus. The study suggests that PGRN should be evaluated as a potential therapy for TBI.
Chimeric antigen receptor T cell (CAR-T) therapy has been shown to be an effective strategy for combatting non-solid tumors; however, CAR-T therapy is still a challenge for solid tumors, such as glioblastoma. To improve CAR-T therapy for glioblastoma, a new TanCAR, comprising the tandem arrangement of IL13 (4MS) and EphA2 scFv, was generated and validated in vitro and in vivo. In vitro, the novel TanCAR-redirected T cells killed glioblastoma tumor cells by recognizing either IL-13 receptor α2 (IL13Rα2) or EphA2 alone or together upon simultaneous encounter of both targets, but did not kill normal cells bearing only the IL13Rα1/IL4Rα receptor. As further proof of principle, the novel TanCAR was tested in a subcutaneous glioma xenograft mouse model. The results indicated that the novel TanCAR-redirected T cells produced greater glioma tumor regression than single CAR-T cells. Thus, the novel TanCAR-redirected T cells kill gliomas more efficiently and selectively than a single IL13 CAR or EphA2 scFv CAR, with the potential for preventing antigen escape and reduced off-target cytotoxicity.
Progranulin (PGRN) is a secreted glycoprotein with multiple biological functions in early embryogenesis, anti-inflammation, and neurodegeneration. A good model for the functional study of PGRN is the zebrafish with knockdown or knockout of grn, the gene encoding PGRN. Morpholino oligonucleotides (MOs) and zinc finger nucleases have been used to generate zebrafish grn models, yet they have shown inconsistent phenotypes due to either the neurotoxicity of the MOs or possible genetic compensation responses during gene editing. In this study, we generated stable grna (one of the major grn homologues of zebrafish) knockout zebrafish by using CRISPR/Cas9-mediated genome editing. A grna sgRNA was designed to target the similar repeated sequence shared by exon 13, exon 15, and exon 19 in zebrafish. The F1 generation with the frameshift mutation of + 4 bp (the addition of 4 bp to exon15), which causes a premature termination, was obtained and subjected to morphological and behavioral evaluation. The grna knockout zebrafish showed neurodevelopmental defects, including spinal motor neurons with shorter axons, decreased sensory hair cells, thinning of the outer nuclear layer and thickening of the inner nuclear layer of the retina, decreased expression of rhodopsin in the cone cells, and motor behavior changes. Moreover, the phenotypes of grna knockout zebrafish could be rescued with the Tol2 system carrying the grna gene. The grna knockout zebrafish model generated in this study provides a useful tool to study PGRN function and has potential for high-throughput drug screening for disease therapy.
Heterozygous loss-of-function mutations in the GRN gene lead to progranulin (PGRN) haploinsufficiency and cause frontotemporal lobar degeneration with TDP-43 pathology type A (FTLD-TDP type A). PGRN is a highly conserved, secreted glycoprotein and functions in the central nervous system as a key modulator of microglial function. Hence, altered microglial function caused by PGRN deficiency may be tied to the pathogenesis of FTLD-TDP. Our previous studies showed that haploinsufficiency of GRN mutations extends to microglial PGRN expression in the hippocampal CA1 region. In this study, we found that the CA1 sector was associated with less neuronal loss and more frequent TDP-43 inclusions in FTLD-TDP type A cases with GRN mutations than in sporadic cases. In addition, the CA1 region in GRN mutation cases contained more rod-like microglia, which also had reduced PGRN expression. These findings suggest that the profile of TDP-43 inclusions, neuronal number, and microgliosis in the CA1 sector of FTLD-TDP type A cases may be influenced by GRN gene expression status.
Mutations in the GRN gene coding for progranulin (PGRN) are responsible for many cases of familial frontotemporal lobar degeneration (FTLD) with TAR DNA-binding protein 43 (TDP-43)-positive inclusions (FTLD-TDP). GRN mutations create null alleles resulting in decreased progranulin protein or haploinsufficiency. FTLD-TDP with GRN mutations is characterized by lentiform neuronal intranuclear inclusions that are positive for TDP-43 in affected brain regions. In this study, by stably expressed short hairpin RNA, we established a neuroblastoma cell line with decreased PGRN level. This cell line reveals TDP-43-positive intranuclear inclusions. In addition, replacement with purified PGRN protein restores normal TDP-43 nuclear distribution. This cell model can be valuable for the study of the role of PGRN in the pathogenesis in FTLD-TDP.
RNA-guided endonuclease Cas9 derived from microbial CRISPR-Cas adaptive immune systems is a powerful tool for genome editing, which has been widely used in eukaryotic systems, prokaryotic systems, and plants. However, the off-target effects caused by Cas9/sgRNA remain a major concern. Currently, the efforts to reduce the off-target effects mainly focus on improving the targeting specificity of sgRNA/Cas9, regulating the activity of the Cas9 protein or the sgRNA, and controlling the time window of their expression. In this study, a novel system was established to regulate the post-transcriptional sgRNA level by small molecule-controlled aptazyme. This system was shown to reduce the off-target effects caused by Cas9/sgRNA, while enabling precise temporal control over gene editing and regulatory activity. This new system could provide a potentially safer and more powerful tool for genome editing and therapeutic application.
To investigate the role of diacylglycerol kinase theta (DGK theta) in lipid metabolism and insulin resistance, the present study generated an in vitro hepatic steatosis cell model by knockout of the DGK theta gene in liver cancer cell line HepG2 using CRISPR/Cas9 technology. The cell line was characterized by Oil Red O staining and shown to exhibit increased intracellular lipid accumulation, compared with that in wild-type liver cancer cell line HepG2. The gene expression levels of signaling proteins in pathways involved in lipid metabolism, insulin resistance and gluconeogenesis were also examined. The DGK theta-knockout HepG2 cells showed increased mRNA and protein expression levels of lipid synthesis-related genes, fatty acid synthase, peroxisome proliferator-activated receptor-gamma and sterol regulatory element-binding protein-1c, and decreased expression levels of the lipolysis-related gene, carnitine palmitoyltransferase1A. These changes may account for the increased intracellular lipid content of this cell line. The DGK theta-knockout HepG2 cells also exhibited an increased phosphorylation level of protein kinase C epsilon and decreased phosphorylation levels of insulin receptor substrate 1, mechanistic target of rapamycin and protein kinase B (also known as Akt). These changes have been reported to mediate insulin resistance. Taken together, an in vitro hepatic steatosis cell model was established in the present study, providing a valuable tool for understanding the pathogenesis of nonalcoholic fatty liver disease and associated insulin resistance, and for developing treatment strategies for this disease.
Human FAM76B (hFAM76B) is a 39 kDa protein that contains homopolymeric histidine tracts, a targeting signal for nuclear speckles. FAM76B is highly conserved among different species, suggesting that it may play an important physiological role in normal cellular functions. However, a lack of appropriate tools has hampered study of this potentially important protein. To facilitate research into the biological function(s) of FAM76B, murine monoclonal antibodies (MAbs) against hFAM76B were generated by using purified, prokaryotically expressed hFAM76B protein. Six strains of MAbs specific for hFAM76B were obtained and characterized. The specificity of MAbs was validated by using FAM76B-/- HEK 293 cell line. Double immunofluorescence followed by laser confocal microscopy confirmed the nuclear speckle localization of hFAM76B, and the specific domains recognized by different MAbs were further elucidated by Western blot. Due to the high conservation of protein sequences between mouse and human FAM76B, MAbs against hFAM76B were shown to react with mouse FAM76B (mFAM76B) specifically. Lastly, FAM76B was found to be expressed in the normal tissues of most human organs, though to different extents. The MAbs produced in this study should provide a useful tool for investigating the biological function(s) of FAM76B.
Enzyme-linked immunosorbent assay (ELISA) has been one of the main methods for detecting an antigen in an aqueous sample for more than four decades. Nowadays, one of the biggest concerns for ELISA is still how to improve the sensitivity of the assay, and the luciferase-luciferin reaction system has been noticed as a new detection method with high sensitivity. In this study, a luciferin-luciferase reaction system was used as the detection method for a sandwich ELISA system. It was shown that this new system led to an increase in the detection sensitivity of at least two times when compared with the traditional horseradish peroxidase (HRP) detection method. Lastly, the serum levels of the human extracellular matrix 1 protein of breast cancer patients were determined by the new system, which were overall similar to the HRP chemiluminescent system. Furthermore, this new luciferase reporter can be implemented into other ELISA systems for the purpose of increasing the assay sensitivity.
In glioblastomas, the surface glycoprotein CD133 (prominin-1) indicates the presence of cancer stem cells (CSCs), which are able to initiate tumor growth and are highly resistant to conventional chemo/radiotherapy. However, a number of studies have reported that certain CD133- glioma cells are able to self-renew and retain tumorigenic potential. In addition, the reliability of CD133 as a CSC marker is controversial due to inconsistent findings with regard to the prognostic values and distribution of CD133. Such controversies may be due to the detection limits using currently available anti-CD133 antibodies. In the present study, novel anti-human CD133 monoclonal antibodies (mAbs) were generated using two recombinant extracellular domains of human CD133: CD133 ectodomain 1 (amino acids 171-420) and CD133 ectodomain 2 (amino acids 507-716). One of the antibodies produced against CD133 ectodomain 2, C2E1, detected high expression levels of CD133 protein in glioblastoma U87 cells, in contrast to previous studies which did not detect CD133 expression in these cells. The cells exhibited a cytoplasmic distribution pattern of CD133 and produced a 95 kDa band following western blot analysis. In addition, C2E1 was able to bind the full-length glycosylated CD133 on the cell surface and inhibit the proliferation of tumor cells. Therefore, this antibody may be a valuable tool to study CD133 as a CSC marker and may be significant in future cancer treatments.
Zinc finger nuclease (ZFN) technology, which can be used to induce targeted genome correction in the presence of a DNA donor template, is becoming an attractive strategy for treating monogenic diseases. This strategy requires efficient delivery of ZFN and donor template into cells, ideally, in a single viral vector to achieve efficient genome editing and to avoid unwanted mutagenesis. In this study, we successfully produced a single adenoviral (Ad) vector with high titer that carried a ZFN expression cassette and a donor template simultaneously. We then demonstrated that this single Ad system could mediate efficient site-specific genome correction in vitro and ex vivo. The gene correction efficiency of the single Ad was significantly higher than that of the double Ad system. This novel vector will be a promising ZFN and donor delivery system for treatment of monogenic diseases.