Magnetic-activated Cell Sorting Research Articles

Generation of primary feline chimeric antigen receptor T cells.

The purpose of this study was to develop procedures to engineer feline chimeric antigen receptor (CAR) T cells. 6 healthy cats were used in this study. Blood was collected, and CD3+ primary T cells were enriched by magnetic activated cell sorting, expanded, and used to generate CAR T cells. Phorbol myristate acetate plus ionomycin and concanavalin A induced similar early proliferation of CD3-enriched feline CD4+ and CD8+ T cells but phorbol myristate acetate plus ionomycin induced greater expansion over 12 days. Chimeric antigen receptor T cells were engineered by transduction with an FIV-based lentiviral system to express a human CD19 CAR. Feline CD19 CAR T cells demonstrated specific cytotoxicity against human CD19+ target cells. Conditions were developed to polarize the T cells to THelper subsets. We generated functional and specific primary feline CAR T cells and demonstrated conditions to polarize the cells, which may be therapeutically advantageous for CAR T-cell use in a variety of disease contexts. CAR T therapy has been used with great success for human hematologic malignancies and is under development for use in canines. Our study is the first demonstration of functional feline CAR T cells and describes the procedures for their engineering. These findings lay the foundation for future development of CAR T therapy for multiple feline diseases.

Depletion of Tregs from CD4+ CAR-Tcells enhances the tumoricidal effect of CD8+ CAR-Tcells in anti-CD19 CAR-T therapy.

Chimeric antigen receptor T (CAR-T) cell therapy, which targets CD19 for hematological malignancies, represents a breakthrough in cancer immunotherapy. However, some patients may develop resistance to CAR-T treatment, underscoring the importance of optimizing CAR-T design to enhance responsiveness. Here, we investigated the impact of different subpopulations in anti-CD19 CAR-T cells on the tumoricidal effect. Different populations of anti-CD19 CAR-T cells were isolated by magnetic-activated cell sorting (MACS). Their lytic activities on the acute lymphocytic leukemia cell line SUP-B15 and diffuse large B-cell lymphoma EB-3 cell line were examined in a co-culture system. The anti-tumorigenic outcome of different CAR-T cell compositions was evaluated in a xenograft mouse model of EB-3 cells. CD8+CAR-T cells exhibited the most potent tumoricidal activity against SUP-B15 and EB-3 cells. Additionally, CD4+ T helper cells enhanced the lytic effects of CD8+ CAR-T cells by increasing the availability of interleukin-2 (IL-2). Depleting CD25+Treg (T regulatory) cells from CD4+CAR-T population further augmented the tumoricidal activity of CD8+CAR-T cells by preventing IL-2 deprivation. Consistently, in vivo experiments demonstrated that the CD4+CD25+ Treg population dampened the antitumor activity of CD8+CAR-T cells, while depletion of Tregs from CD4+CAR-T cells enhanced the tumoricidal effect. These findings emphasize the potential role of CAR Treg cells in therapeutic resistance, suggesting that the depletion of Tregs in the anti-CD19 CAR-T population may serve as a strategy to augment the anticancer effect of CD8+CAR-T cells.

Microglial cannabinoid receptor type II stimulation improves cognitive impairment and neuroinflammation in Alzheimer's disease mice by controlling astrocyte activation.

Alzheimer's disease (AD) is the most common form of dementia and is characterized by the accumulation of amyloid β (Aβ) and phosphorylated tau. Neuroinflammation, mainly mediated by glial activation, plays an important role in AD progression. Although there is growing evidence for the anti-neuroinflammatory and neuroprotective effects of the cannabinoid system modulation, the detailed mechanism remains unclear. To address these issues, we analyzed the expression levels of cannabinoid receptor type II (Cnr2/Cb2) in AppNL-G-F/NL-G-F mice and human AD precuneus, which is vulnerable to amyloid deposition in AD, and the effects of JWH 133, a selective CB2 agonist, on neuroinflammation in primary glial cells and neuroinflammation and cognitive impairment in AppNL-G-F/NL-G-F mice. The levels of Cnr2/Cb2 were upregulated in microglia isolated from the cerebral cortex of AppNL-G-F/NL-G-F mice. CNR2 expression was also increased in RNAs derived from human precuneus with advanced AD pathology. Chronic oral administration of JWH 133 significantly ameliorated the cognitive impairment of AppNL-G-F/NL-G-F mice without neuropsychiatric side effects. Microglia and astrocyte mRNAs were directly isolated from the mouse cerebral cortex by magnetic-activated cell sorting, and the gene expression was determined by quantitative PCR. JWH 133 administration significantly decreased reactive astrocyte markers and microglial C1q, an inducer for the reactive astrocytes in AppNL-G-F/NL-G-F mice. In addition, JWH133 administration inhibited the expression of p-STAT3 (signal transducer and activator of transcription 3) in astrocytes in AppNL-G-F/NL-G-F mice. Furthermore, JWH 133 administration suppressed dystrophic presynaptic terminals surrounding amyloid plaques. In conclusion, stimulation of microglial CB2 ameliorates cognitive dysfunction in AppNL-G-F/NL-G-F mice by controlling astrocyte activation and inducing beneficial neuroinflammation, and our study has implications that CB2 may represent an attractive therapeutic target for the treatment of AD and perhaps other neurodegenerative diseases involving neuroinflammation.

A protocol to isolate and characterize pure monocytes and generate monocyte-derived dendritic cells through FBS-Coated flasks

This study explores methods to isolate high-pure monocytes and optimize the best growth factor concentration to generate monocytes-derived dendritic cells (mo-DCs), subset DC1, which is crucial in immune responses. Three protocols for monocyte isolation from peripheral blood mononuclear cells (PBMCs) were evaluated: three-hour incubation on FBS-coated flasks; an overnight incubation on FBS-coated flasks; and Magnetic Activated Cell Sorting (MACS). Additionally, five different concentrations of human recombinant granulocyte-macrophage colony-stimulating factor (hrGM-CSF) and human recombinant interleukin-4 (hrIL-4) were compared. We used Flow cytometry to assess the isolation, purification, and generation of pure monocytes characterized as CD14+, and expression of mo-DC classical markers (HLA-DR, CD80, CD83, and CD86). The obtained results show that monocytes isolated with the second method (overnight incubation) had the highest purity (P < 0.0001) but the lowest yield (P > 0.05), balancing purity and cost-effectiveness. A combination of hrGM-CSF and hrIL-4 at 400 U/mL produced the most favorable outcomes, leading to the highest rate of mo-DC generation (P < 0.05). Notably, this concentration resulted in increasing expression of HLA-DR, CD80, and CD86 surface markers in the generated DCs (P < 0.0001), with no changes in CD83 expression levels. In conclusion, this study offers valuable insights into selecting the optimal approach for monocyte isolation and mo-DC generation in various research contexts, providing a foundation for more effective immunological studies.

Proteomic analysis of CD29+ Müller cells reveals metabolic reprogramming in rabbit myopia model

The prevalence of myopia is rapidly increasing, significantly impacting the quality of life of affected individuals. Prior research by our group revealed reactive gliosis in Müller cells within myopic retina, prompting further investigation of their role in myopia, which remains unclear. In this study, we analyzed protein expression changes in CD29+ Müller cells isolated from a form deprivation-induced rabbit model of myopia using magnetic activated cell sorting to investigate the role of these cells in myopia. As the principal glial cells in the retina, Müller cells exhibited significant alterations in the components of metabolic pathways, particularly glycolysis and angiogenesis, including the upregulation of glycolytic enzymes, such as lactate dehydrogenase A and pyruvate kinase, implicated in the adaptation to increased metabolic demands under myopic stress. Additionally, a decrease in the expression of proteins associated with oxygen transport suggested enhanced vulnerability to oxidative stress. These findings highlight the proactive role of CD29+ Müller cells in modifying the retinal environment in response to myopic stress and provide valuable insights into mechanisms that could help mitigate myopia progression.

6432 Enriching Testicular Organoid Aggregates to Promote Germ Cell Homing

Abstract Disclosure: A. Patel: None. O.O. Printy: None. C. Joswiak: None. M.M. Laronda: None. The long-term effects of life-saving chemotherapy treatments, such as an increased risk of infertility, are of concern to the growing number of childhood cancer survivors. De novo testicular morphogenesis seeks to generate testicular organoids that are structurally and functionally similar to the native testis. These organoids serve as a tool for investigating patient-specific models for restoring spermatogenesis for prepubertal cancer patients. Our lab has previously developed testicular organoids containing tubule-like structures (TLS) resembling the native seminiferous tubules as assessed by immunohistochemistry of testicular cell-type markers for Leydig cells (HSD3B2), peritubular myoid cells (ACTA1), Sertoli cells (SOX9), germ cells (DDX4), and spermatogonial stem cells (SSCs) (SALL4). Internal architecture demonstrated semi-continuous ring-like structures composed of ACTA1-positive cells encapsulating a population of SOX9-positive cells with HSD3B2-positive cells clustering near the periphery of the organoids. However, organoids lacked native germ cell populations. We hypothesized that murine testicular organoids would merge to form elongated TLS, within which exogenous SSCs would home to existing Sertoli cell niches, when cultured within structures designed from the appropriate dimensions and materials. Organoids were generated from testicular tissue isolated from 5 days-post-partum (dpp) CD1 mice using cell-seeding densities and microenvironmental conditions previously established by our lab. To promote aggregate formation, 48-hour-old organoids were transferred to trough-shaped structures formed from 2% agarose using 3D printed silicone molds. Separately, SSCs were isolated from 5 dpp tdTomato+ mice via magnetic-activated cell sorting of THY1+ cells. Organoids and aggregates were enriched with SSCs by three methods: (1) enrichment of cell suspension during organoid formation, (2) enrichment of culture during aggregate formation, and (3) injection of SSCs into aggregate using 20 µm glass pipette. Organoids transferred to agarose troughs on day 2 of culture merged to form aggregates by day 5 and continued to display dynamic architecture, shortening in length and increasing in width over time. Aggregates were more elongated in shape when cultured in narrow troughs less than 700µm in width. Observations thus far indicate that attempts to inject aggregates resulted in penetrance and inclusion of the SSC suspension; additionally, tdTomato+ cells were visualized within injected aggregates on day 17 of culture. Research is ongoing to define where exogenous SSCs take up residence, how long they survive, and if they proliferate over time within the testicular aggregates. This research expands upon foundational work establishing testicular organoids as an approach to in vitro spermatogenesis with clinical applications in fertility restoration. Presentation: 6/2/2024

6432 Enriching Testicular Organoid Aggregates to Promote Germ Cell Homing

Abstract Disclosure: A. Patel: None. O.O. Printy: None. C. Joswiak: None. M.M. Laronda: None. The long-term effects of life-saving chemotherapy treatments, such as an increased risk of infertility, are of concern to the growing number of childhood cancer survivors. De novo testicular morphogenesis seeks to generate testicular organoids that are structurally and functionally similar to the native testis. These organoids serve as a tool for investigating patient-specific models for restoring spermatogenesis for prepubertal cancer patients. Our lab has previously developed testicular organoids containing tubule-like structures (TLS) resembling the native seminiferous tubules as assessed by immunohistochemistry of testicular cell-type markers for Leydig cells (HSD3B2), peritubular myoid cells (ACTA1), Sertoli cells (SOX9), germ cells (DDX4), and spermatogonial stem cells (SSCs) (SALL4). Internal architecture demonstrated semi-continuous ring-like structures composed of ACTA1-positive cells encapsulating a population of SOX9-positive cells with HSD3B2-positive cells clustering near the periphery of the organoids. However, organoids lacked native germ cell populations. We hypothesized that murine testicular organoids would merge to form elongated TLS, within which exogenous SSCs would home to existing Sertoli cell niches, when cultured within structures designed from the appropriate dimensions and materials. Organoids were generated from testicular tissue isolated from 5 days-post-partum (dpp) CD1 mice using cell-seeding densities and microenvironmental conditions previously established by our lab. To promote aggregate formation, 48-hour-old organoids were transferred to trough-shaped structures formed from 2% agarose using 3D printed silicone molds. Separately, SSCs were isolated from 5 dpp tdTomato+ mice via magnetic-activated cell sorting of THY1+ cells. Organoids and aggregates were enriched with SSCs by three methods: (1) enrichment of cell suspension during organoid formation, (2) enrichment of culture during aggregate formation, and (3) injection of SSCs into aggregate using 20 µm glass pipette. Organoids transferred to agarose troughs on day 2 of culture merged to form aggregates by day 5 and continued to display dynamic architecture, shortening in length and increasing in width over time. Aggregates were more elongated in shape when cultured in narrow troughs less than 700µm in width. Observations thus far indicate that attempts to inject aggregates resulted in penetrance and inclusion of the SSC suspension; additionally, tdTomato+ cells were visualized within injected aggregates on day 17 of culture. Research is ongoing to define where exogenous SSCs take up residence, how long they survive, and if they proliferate over time within the testicular aggregates. This research expands upon foundational work establishing testicular organoids as an approach to in vitro spermatogenesis with clinical applications in fertility restoration. Presentation: 6/2/2024

Human sensory-like neuron cultivation-An optimized protocol.

Reprogramming of human-induced pluripotent stem cells (iPSCs) and their differentiation into specific cell types, such as induced sensory-like neurons (iSNs), are critical for disease modeling and drug testing. However, the variability of cell populations challenges reliability and reproducibility. While various protocols for iSN differentiation exist, the development of non-iSN cells in these cultures remains an issue. Therefore, standardization of protocols is essential. This study aimed to improve iSN culture conditions by reducing the number of non-iSN cells while preserving the survival and quality of iSNs. iSNs were differentiated from a healthy control iPSC line using an established protocol. Interventions for protocol optimization included floxuridine (FdU) or 1-β-D-arabinofuranosyl-cytosine hydrochloride (AraC) treatment, magnetic-activated cell sorting (MACS), early cell passaging, and replating. Cell viability and iSN-to-total-cell-count ratio were assessed using a luminescent assay and immunocytochemistry, respectively. Passaging of cells during differentiation did not increase the iSN-to-total-cell-count ratio, and MACS of immature iSNs led to neuronal blebbing and reduced the iSN-to-total-cell-count ratio. Treatment with high concentrations and prolonged incubation of FdU or AraC resulted in excessive cell death. However, treatment with 10 μM FdU for 24 h post-differentiation showed the most selective targeting of non-iSN cells, leading to an increase in the iSN-to-total-cell count ratio without compromising the viability or functionality of the iSN population. Replating of iSNs shortly after seeding also helped to reduce non-iSN cells. In direct comparison with other methods, treatment with 10 μM FdU for 24 h after differentiation shows promise for improving iSN culture purity, which could benefit downstream applications in disease modeling and drug discovery. However, further investigations involving multiple iPSC lines and optimization of protocol parameters are warranted to fully exploit the potential of this method and enhance its reproducibility and applicability. Overall, this study provides valuable insights into optimizing culture conditions for iSN differentiation and highlights the importance of standardized protocols in iPSC-based research.

Investigating the IgM and IgG B Cell Receptor Repertoires and Expression of Ultralong Complementarity Determining Region 3 in Colostrum and Blood from Holstein-Friesian Cows at Calving.

In cattle, colostral maternal immunoglobulins and lymphocytes transfer across the neonate's intestinal epithelium to provide protection against pathogens. This study aimed to compare repertoires of B cell populations in blood and colostrum in cows for the first time, with an emphasis on ultralong complementarity determining region 3 (CDR3, ≥40 amino acids). Blood mononuclear cells (BMCs, n= 7) and colostral cells (n = 7) were isolated from Holstein-Friesian dairy cows. Magnetic-activated cell sorting was used to capture IgM and IgG B cells from BMCs. Colostral cells were harvested by centrifugation. RNA was extracted and cDNA was produced; IgM and IgG transcripts were amplified using polymerase chain reactions. Amplicons were sequenced using the Nanopore Native barcoding kit 24 V14 and MinION with R10.4 flow cells. In colostrum, there was a significantly greater percentage of IgM B cells with ultralong CDR3s (8.09% ± 1.73 standard error of the mean) compared to blood (4.22% ± 0.70, p = 0.05). There was a significantly greater percentage of IgG B cells in colostrum with ultralong CDR3s (12.98% ± 1.98) compared to blood (6.61% ± 1.11, p = 0.05). A higher percentage of IgM and IgG B cells with ultralong CDR3s in colostrum may be indicative of a potential role in protecting the neonate.

27-Hydroxycholesterol Negatively Affects the Function of Bone Marrow Endothelial Cells in the Bone Marrow.

Hematopoietic stem cells (HSCs) reside in specific microenvironments that facilitate their regulation through both internal mechanisms and external cues. Bone marrow endothelial cells (BMECs), which are found in one of these microenvironments, play a vital role in controlling the self-renewal and differentiation of HSCs during hematological stress. We previously showed that 27-hydroxycholesterol (27HC) administration of exogenous 27HC negatively affected the population of HSCs and progenitor cells by increasing the reactive oxygen species levels in the bone marrow. However, the effect of 27HC on BMECs is unclear. To determine the function of 27HC in BMECs, we employed magnetic-activated cell sorting to isolate CD31+ BMECs and CD31- cells. We demonstrated the effect of 27HC on CD31+ BMECs and HSCs. Treatment with exogenous 27HC led to a decrease in the number of BMECs and reduced the expression of adhesion molecules that are crucial for maintaining HSCs. Our results demonstrate that BMECs are sensitively affected by 27HC and are crucial for HSC survival.

The Impact of Magnetic Activated Cell Sorting (MACS) on Assisted Reproduction Outcomes

Objectives The study’s objectives were to evaluate the benefits of adding the magnetically activated cell sorting (MACS) technique to the traditional density gradient sperm wash method for advanced sperm selection in intracytoplasmic sperm injection (ICSI) cycles by comparing fertilisation rates, embryo quality, blastocyst formation, and pregnancy rates. Material and Methods A retrospective observational study was conducted at ARMC Aegis Hospital Perinthalmanna, Kerala. The study group was 116 patients taken during ICSI cycles done from October 2021 to September 2023, with 58 patients in the study (MACS after density gradient centrifugation) and 58 in control (density gradient centrifugation alone). Cases and controls were determined by the willingness of the patient to do MACS in sperm selection after discussion with their clinician. Patients with a severe male factor with sperm morphology &lt;4% were included in the study, with the female partner having regular cycles, normal AFC, and AMH &gt; 1 ng/ml. Patients with seminal infection, known genetic errors, female partners with endometriosis, PCOS, infections, malformations and previous poor responders were excluded. Spermatozoa are incubated with microbeads for 15 min at room temperature (100 μl/10 million) in MACS, after which they are placed into a separation column that contains magnetised iron spheres in it that is magnetised. While the unlabelled cells flow through the MACS column, the micro-bead labelled cells are trapped there subsequently, ICSI was performed using the processed sperm sample. The 2PN (Pro-nuclei) embryos, blastocysts, embryo quality, clinical pregnancies, and live births were noted and statistically analysed. Results The study and control groups were demographically similar; both cases (MACS group) and control group Density Gradient Centrifugation (DGC) group were under a 95% confidence interval. Results of the MACS group were compared with the DGC group. 2 PN status, number of embryos, Grade I embryos, day 5 blastocyst formation, live birth rates, and the number of positive pregnancies were examined in both groups. Analysis showed an increase in the 2 PN status, number of embryos, Grade I embryos, and day 5 blastocyst formation in the MACS group compared to the conventional DGC method. However, embryo grades (Grade I embryos) in the MACS group were high compared to the DGC group (P-value &lt; 0.01). Conclusion For couples with severe male factors and defective sperm morphology, the study finds that MACS may be recommended as an additional option to standard sperm processing.

Isolating Microglia from Mouse Brain Demyelinating Lesions Using Magnetic Activated Cell Sorting

Isolating Microglia from Mouse Brain Demyelinating Lesions Using Magnetic Activated Cell Sorting

Isolating Microglia from Mouse Brain Demyelinating Lesions Using Magnetic Activated Cell Sorting

Isolating Microglia from Mouse Brain Demyelinating Lesions Using Magnetic Activated Cell Sorting

Isolation and Whole-Cell Patch-Clamp Recording of Hippocampal Microglia from Adult Mice.

Microglia are resident immune cells in the brain that interact with neurons to maintain the homeostasis of the central nervous system (CNS). Studies show that the microglial surface expresses potassium channels that regulate microglial activation, while abnormalities in these potassium channels can lead to neural diseases. Currently, whole-cell patch-clamp recordings of microglia are mostly performed on cultured primary microglia from fetal or newborn mice due to difficulties in conducting electrophysiological evaluations on acutely isolated microglia. This study introduces an easy-to-follow protocol for isolating hippocampal microglia from adult mice and performing whole-cell patch-clamp recordings on the isolated cells. Briefly, the brain was removed from a mouse after decapitation, the hippocampus was dissected bilaterally, and microglia were isolated using an adult mouse brain dissociation kit. The microglia were then purified using a magnetic-activated cell sorting (MACS) method and seeded onto coverslips. Successful microglial isolation was confirmed by immunofluorescent staining with anti-CD11 and anti-Iba1 antibodies. A cover slip was placed in a recording chamber, and the whole-cell potassium currents of the acutely isolated microglia were recorded under voltage-clamp conditions.

Single-cell RNA sequencing reveals surface markers of primordial germ cells in chicken and zebra finch.

Primordial germ cells (PGCs) in avian species exhibit unique developmental features, including the ability to migrate through the bloodstream and colonize the gonads, allowing their isolation at various developmental stages. Several methods have been developed for the isolation of avian PGCs, including density gradient centrifugation, size-dependent separation, and magnetic-activated cell sorting (MACS) or fluorescence-activated cell sorting (FACS) using a stage-specific embryonic antigen-1 (SSEA-1) antibody. However, these methods present limitations in terms of efficiency and applicability across development stages. In particular, the specificity of SSEA-1 decreases in later developmental stages. Furthermore, surface markers that can be utilized for isolating or utilizing PGCs are lacking for wild birds, including zebra finches, and endangered avian species. To address this, we used single-cell RNA sequencing (scRNA-seq) to uncover novel PGC-specific surface markers in chicken and zebra finch. We screened for genes that were primarily expressed in the PGC population within the gonadal cells. Analyses of gene expression patterns and levels based on scRNA-seq, coupled with validation by RT-PCR, identified NEGR1 and SLC34A2 as novel PGC-specific surface markers in chickens and ESYT3 in zebra finches. Notably, these newly identified genes exhibited sustained expression not only during later developmental stages but also in reproductive tissues.

L-carnitine cause to increase cell proliferation of C-Kit+ hematopoietic progenitor cells via decreasing the PI3K and FOXO-1 protein expression

BackgroundStem cell-based therapy has emerged as an attractive approach for regenerative medicine. Poor survival and maintenance of the cells used in regenerative medicine are considered as serious barriers to enhance the efficacy of the cell therapy. Using some antioxidants has been reported to prevent the aging of stem cells, and finding effective factors to reduce the senescence of these cells has impressive potential in cell therapy. The PI3K pathway adversely regulates the transcription factors known as FOXO, which are thought to have an inhibitory influence on cell proliferation. By downregulating FOXO and other targets, PI3K signaling controls the growth of cells. For this reason, the aim of the present study is to investigate the effect of L-carnitine (LC) as antioxidant on the cell proliferation and the protein expression of PI3K and FOXO. MethodsFor understanding the in vitro effect of LC on the PI3K and FOXO-1 expression of C-kit+ hematopoietic progenitor cells, the bone marrow mononuclear cells were isolated, and C-kit+ cells was enriched by the magnetic-activated cell sorting (MACS). Next, the identification of enriched C-kit+ cells were done by flowcytometry and immunocytochemistry. Then, C-kit+ cells were treated with 0.2 mM LC, the cells were collected at the end of the treatment period (48 h), and the proteins were extracted. In the following, the protein expression of PI3K and FOXO-1 was measured by western blotting. In addition, flowcytometry was done to assess the Ki-67 expression as a key marker for cell proliferation investigation. Results0.2 mM LC cause to significantly decrease in the protein expression of PI3K and FOXO-1 (*P<0.05 and **P<0.01, respectively). Also, the expression of Ki-67 was significantly increased in the presence of 0.2 mM LC (***P<0.001). ConclusionBriefly, LC can be considered an effective factor in increasing the proliferation of C-kit+ cells via some signaling pathways.

A General Method to Screen Nanobodies for Cytochrome P450 Enzymes from a Yeast Surface Display Library.

The availability of yeast surface display nanobody (Nb) libraries offers a convenient way to acquire antigen-specific nanobodies that may be useful for protein structure-function studies and/or therapeutic applications, complementary to the conventional method of acquiring nanobodies through immunization in camelids. In this study, we developed a general approach to select nanobodies for cytochrome P450 enzymes from a highly diverse yeast display library. We tested our method on three P450 enzymes including CYP102A1, neuronal nitric oxide synthase (nNOS), and the complex of CYP2B4:POR, using a novel streamlined approach where biotinylated P450s were bound to fluorescent-labeled streptavidin for Nb screening. The Nb-antigen binders were selectively enriched using magnetic-activated cell sorting (MACS) and fluorescence-activated cell sorting (FACS). After two rounds of MACS, the population of positive binders was enriched by >5-fold compared to the naïve library. The subsequent FACS selection, with a gating of 0.1%, identified 634, 270, and 215 positive binders for CYP102A1, nNOS, and CYP2B4:POR, respectively. The positive binders for CYP102A1 were further triaged based on EC50 determined at various antigen concentrations. DNA sequencing of the top 30 binders of CYP102A1 resulted in 26 unique clones, 8 of which were selected for over-expression and characterization. They were found to inhibit CYP102A1-catalyzed oxidation of omeprazole with IC50 values in the range of 0.16-2.8 µM. These results validate our approach and may be applied to other protein targets for the effective selection of specific nanobodies.

Pericytes recruited by CCL28 promote vascular normalization after anti-angiogenesis therapy through RA/RXRA/ANGPT1 pathway in lung adenocarcinoma

BackgroundIt has been proposed that anti-angiogenesis therapy could induce tumor "vascular normalization" and further enhance the efficacy of chemotherapy, radiotherapy, target therapy, and immunotherapy for nearly twenty years. However, the detailed molecular mechanism of this phenomenon is still obscure.MethodOverexpression and knockout of CCL28 in human lung adenocarcinoma cell line A549 and murine lung adenocarcinoma cell line LLC, respectively, were utilized to establish mouse models. Single-cell sequencing was performed to analyze the proportion of different cell clusters and metabolic changes in the tumor microenvironment (TME). Immunofluorescence and multiplex immunohistochemistry were conducted in murine tumor tissues and clinical biopsy samples to assess the percentage of pericytes coverage. Primary pericytes were isolated from lung adenocarcinoma tumor tissues using magnetic-activated cell sorting (MACS). These pericytes were then treated with recombinant human CCL28 protein, followed by transwell migration assays and RNA sequencing analysis. Changes in the secretome and metabolome were examined, and verification of retinoic acid metabolism alterations in pericytes was conducted using quantitative real-time PCR, western blotting, and LC–MS technology. Chromatin immunoprecipitation followed by quantitative PCR (ChIP-qPCR) was employed to validate the transcriptional regulatory ability and affinity of RXRα to specific sites at the ANGPT1 promoter.ResultsOur study showed that after undergoing anti-angiogenesis treatment, the tumor exhibited a state of ischemia and hypoxia, leading to an upregulation in the expression of CCL28 in hypoxic lung adenocarcinoma cells by the hypoxia-sensitive transcription factor CEBPB. Increased CCL28 could promote tumor vascular normalization through recruiting and metabolic reprogramming pericytes in the tumor microenvironment. Mechanistically, CCL28 modified the retinoic acid (RA) metabolism and increased ANGPT1 expression via RXRα in pericytes, thereby enhancing the stability of endothelial cells.ConclusionWe reported the details of the molecular mechanisms of "vascular normalization" after anti-angiogenesis therapy for the first time. Our work might provide a prospective molecular marker for guiding the clinical arrangement of combination therapy between anti-angiogenesis treatment and other therapies.

Single-cell RNA Sequencing Identifies a Novel Subtype of Microglia with High Cd74 Expression that Facilitates White Matter Inflammation During Chronic Cerebral Hypoperfusion.

Vascular dementia (VaD) causes progressive cognitive decline in the elderly population, but there is short of available therapeutic measures. Microglia-mediated neuroinflammation is vigorously involved in the pathogenesis of VaD, but the traditional classification of microglial M1/M2 phenotypes remains restrictive and controversial. This study aims to investigate whether microglia transform into novel subtypes in VaD. Chronic cerebral hypoperfusion (CCH) rat model was constructed to mimic VaD. Microglia were isolated via magnetic-activated cell sorting and analyzed by single-cell RNA sequencing (scRNA-seq) and bioinformatics. The findings inferred from scRNA-seq and bioinformatics were further validated through in vivo experiments. In this study, microglia were divided into eight clusters. The proportion of MG5 cluster was significantly increased in the white matter of the CCH group compared with the Sham group and was named chronic ischemia-associated microglia (CIAM). Immunity- and inflammation-related genes, including RT1-Db1, RT1-Da, RT1-Ba, Cd74, Spp1, C3, and Cd68, were markedly upregulated in CIAM. Enrichment analysis illustrated that CIAM possessed the function of evoking neuroinflammation. Further studies unveiled that Cd74 is associated with the most abundant GO terms involved in inflammation as well as cell proliferation and differentiation. In addition, microglia-specific Cd74 knockdown mediated by adeno-associated virus decreased the abundance of CIAM in the white matter, thereby mitigating inflammatory cytokine levels, alleviating white matter lesions, and improving cognitive impairment for CCH rats. These findings indicate that Cd74 is the core molecule of CIAM to trigger neuroinflammation and induce microglial differentiation to CIAM, suggesting that Cd74 may be a potential therapeutic target for VaD.

Endothelial histone deacetylase 1 activity impairs kidney microvascular NO signaling in rats fed a high-salt diet.

We aimed to test the hypothesis that a high-salt diet (HS) impairs NO signaling in kidney microvascular endothelial cells through a histone deacetylase 1 (HDAC1)-dependent mechanism. Male Sprague Dawley rats were fed normal salt diet (NS; 0.49% NaCl) or HS (4% NaCl) for 2 weeks. NO signaling was assessed by measuring L-NAME induced vasoconstriction of the afferent arteriole using the blood perfused juxtamedullary nephron (JMN) preparation. In this preparation, kidneys were perfused with blood from a donor rat on a matching or different diet to that of the kidney donor. Kidney endothelial cells were isolated with magnetic activated cell sorting and HDAC1 activity was measured. We found HS-induced impaired NO signaling in the afferent arteriole. This was restored by inhibition of HDAC1 with MS-275. Consistent with these findings, HDAC1 activity was increased in kidney endothelial cells. We further found the loss of NO to be dependent upon the diet of the blood donor rather than the diet of the kidney donor and the plasma from HS-fed rats to be sufficient to induce impaired NO signaling. This indicates the presence of a humoral factor we termed plasma-derived endothelial dysfunction mediator (PDEM). Pretreatment with the antioxidants, PEG-SOD and PEG-catalase, as well as the NOS cofactor, tetrahydrobiopterin, restored NO signaling. We conclude that HS activates endothelial HDAC1 through PDEM leading to decreased NO signaling. This study provides novel insights into the molecular mechanisms by which a HS decreases renal microvascular endothelial NO signaling.