4D Cell Biology: Adaptive optics lattice light-sheet imaging and AI powered big data processing of live stem cell-derived organoids


New methods in stem cell 3D organoid tissue culture, advanced imaging, and big data image analytics now allow tissue-scale 4D cell biology but currently available analytical pipelines are inadequate for handing and analyzing the resulting gigabytes and terabytes of high-content imaging data. We expressed fluorescent protein fusions of clathrin and dynamin2 at endogenous levels in genome- edited human embryonic stem cells, which were differentiated into intestinal epithelial organoids.

Lattice light-sheet imaging with adaptive optics (AO-LLSM) allowed us to image large volumes of these organoids (70 × 60 × 40 μm xyz) at 5.7 s/frame. We developed an open-source data analysis package termed pyLattice to process the resulting large (∼60 Gb) movie data sets and to track clathrin-mediated endocytosis (CME) events.

We then expressed fluorescent protein fusions of actin and tubulin in genome-edited induced human pluripotent stem cells, which were differentiated into human cortical organoids. Using the AO-LLSM mode on the new MOSAIC (Multimodal Optical Scope with Adaptive Imaging Correction) allowed us to image neuronal migration deep in the organoid. We augmented pyLattice with a deep learning module and used it to process the brain organoid data.

Common Sources of Inflammation and Their Impact on Hematopoietic Stem Cell Biology


Purpose of review: Inflammatory signals have emerged as critical regulators of hematopoietic stem cell (HSC) function. Specifically, HSCs are highly responsive to acute changes in systemic inflammation and this influences not only their division rate but also their lineage fate. Identifying how inflammation regulates HSCs and shapes the blood system is crucial to understanding the mechanisms underpinning these processes, as well as potential links between them.


Recent findings: A widening array of physiologic and pathologic processes involving heightened inflammation are now recognized to critically affect HSC biology and blood lineage production. Conditions documented to affect HSC function include not only acute and chronic infections but also autoinflammatory conditions, irradiation injury, and physiologic states such as aging and obesity.


Summary: Recognizing the contexts during which inflammation affects primitive hematopoiesis is essential to improving our understanding of HSC biology and informing new therapeutic interventions against maladaptive hematopoiesis that occurs during inflammatory diseases, infections, and cancer-related disorders.

Long-chain polyunsaturated omega-3 fatty acids reduce multiple myeloma exosome-mediated suppression of NK cell cytotoxicity


Background: Despite the advances in the treatment of multiple myeloma (MM), complete remission is usually challenging. The interactions between tumor and host cells, in which exosomes (EXs) play critical roles, have been shown to be among the major deteriorative tumor-promoting factors herein. Therefore, any endeavor to beneficially target these EX-mediated interactions could be of high importance.


Objectives: a) To investigate the effects of myeloma EXs on natural killer (NK) cell functions. b) To check whether treatment of myeloma cells with eicosapentaenoic acid (EPA) or docosahexaenoic acid (DHA), two polyunsaturated omega-3 fatty acids with known anti-cancer effects, can modify myeloma EXs in terms of their effects on natural killer functions.


Methods: L363 cells were treated with either EPA or DHA or left untreated and the released EXs (designated as E-EX, D-EX and C-EX, respectively) were used to treat NK cells for functional studies.


Results: Myeloma EXs (C-EXs) significantly reduced NK cytotoxicity against K562 cells (P ≤ 0.05), while the cytotoxicity suppression was significantly lower (P ≤ 0.05) in the (E-EX)- and (D-EX)-treated NK cells compared to the (C-EX)-treated cells. The expression of the activating NK receptor NKG2D and NK degranulation, after treatment with the EXs, were both altered following the same pattern. However, C-EXs could increase IFN-γ production in NK cells (P < 0.01), which was not significantly affected by EPA/DHA treatment. This indicates a dual effect of myeloma EXs on NK cells functions.


Conclusion: Our observations showed that myeloma EXs have both suppressive and stimulatory effects on different NK functions. Treatment of myeloma cells with EPA/DHA can reduce the suppressive effects of myeloma EXs while maintaining their stimulatory effects. These findings, together with the previous findings on the anti-cancer effects of EPA/DHA, provide stronger evidence for the repositioning of the currently existing EPA/DHA supplements to be used in the treatment of MM as an adjuvant treatment.

EXs released from L363 (myeloma) cells in their steady state increase IFN-γ production of NK cells, while reduce their cytotoxicity against the K562 cell line (right blue trace). EXs from L363 cells pre-treated with either EPA or DHA are weaker stimulators of IFN-γ production.

These EXs also increase NK cytotoxicity and NKG2D expression (left brown trace) compared to the EXs obtained from untreated L363 cells. Based on these findings, myeloma EXs have both suppressive and stimulatory effects on different NK functions depending on the properties of their cells of origin, which can be exploited in the treatment of myeloma.


Bone Marrow Mesenchymal Stem Cell Exosomes Promote Brain Microvascular Endothelial Cell Proliferation and Migration in Rats]

Objective: To study the effect of bone marrow mesenchyml stem cell (BMSC) exosomes (Exo) on the proliferation and migration of brain microvascular endothelial cells in rats.


Methods: BMSCs were extracted from rats and identified. The BMSCs were co-cultured with bEnd.3 cells in Transwell chamber for 24 h (BMSCs group). Extracted and identified the BMSCs exosomes (BMSC-Exo). Observed and qualitatively evaluated the cells’ abilities on swallowing the BMSC-Exo under a fluorescence microscope. The optimal work concentration of BMSC-Exo was selected by detecting the cell vitality under different BMSC-Exo concentrations by CCK8 method. bEnd.3 cells were co-cultured with BMSC-Exo for 24 h (BMSC-Exo group). bEnd.3 cells cultured alone was set as control group. The proliferation and migration of bEnd.3 cells in the three groups were respectively detected by EDU and cell scratching experiment after 24 h of culture.


Results: Flow cytometry showed that P3 BMSCs were CD90 and CD29 positive and CD45 negative, with osteogenic differentiation and adipogenesis differentiation, indicating the extracted BMSCs high purity. The BMSC-Exo under transmission electron microscopy was round-shaped with a diameter of about 100 nm; NTA analysis found the diameter distribution of BMSC-Exo ranged from 50 to 600 nm, with a peak size of 150 nm. Immunofluorescence showed that the endothelial cells could swallow BMSC-Exo. CCK8 showed that supplement of 20 μg/mL BMSC-Exo had the best effect on cell proliferation.


EDU results showed that BMSCs group and BMSC-Exo group could promote the proliferation of bEnd.3 cells compared with the control group (P<0.05), and there was no difference between BMSCs group and BMSC-Exo group (P>0.05). Cell scratch test showed that the cell mobility of the BMSC-Exo group was higher than that of the control group (P<0.05), but there was no significant difference between the BMSC-Exo group and the BMSCs group (P>0.05).


Conclusion: BMSC-Exo can replace BMSCs in effectively promoting the proliferation and migration of cerebral microvascular endothelial cells, which provide a new potential treatment for angiogenesis after stroke.

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