Droplet digital polymerase chain reaction-based quantitation of therapeutic lentiviral vector copies in transduced hematopoietic stem cells

BACKGROUND AIMS

Gene therapy using lentiviral vectors (LVs) that harbor a functional β-globin gene provides a curative treatment for hemoglobinopathies including beta-thalassemia and sickle cell disease. Accurate quantification of the vector copy number (VCN) and/or the proportion of transduced cells is critical to evaluate the efficacy of transduction and stability of the transgene during treatment. Moreover, commonly used techniques for LV quantification, including real-time quantitative polymerase chain reaction (PCR) or fluorescence-activated cell sorting, require either a standard curve or expression of a reporter protein for the detection of transduced cells. In the present study, we describe a digital droplet PCR (ddPCR) technique to measure the lentiviral VCN in transduced hematopoietic stem and progenitor cells (HSPCs).

METHODS

After HSPCs were transduced with an LV encoding the therapeutic β-globin (βA-T87Q) gene, the integrated lentiviral sequence in the host genome was amplified with primers that targeted a sequence within the vector and the human RPP30 gene. The dynamic range of ddPCR was between 5 × 10-3 ng and 5 × 10-6 ng of target copy per reaction.

RESULTS

We found that the ddPCR-based approach was able to estimate VCN with high sensitivity and a low standard deviation. Furthermore, ddPCR-mediated quantitation of lentiviral copy numbers in differentiated erythroblasts correlated with the level of βA-T87Q protein detected by reverse-phase high-performance liquid chromatography.

CONCLUSIONS

Taken together, the ddPCR technique has the potential to precisely detect LV copy numbers in the host genome, which can be used for VCN estimation, calculation of infectious titer and multiplicity of infection for HSPC transduction in a clinical setting.

An increase in ER stress and unfolded protein response in iPSCs-derived neuronal cells from neuronopathic Gaucher disease patients

Gaucher disease (GD) is a lysosomal storage disorder caused by a mutation in the GBA1 gene, responsible for encoding the enzyme Glucocerebrosidase (GCase). Although neuronal death and neuroinflammation have been observed in the brains of individuals with neuronopathic Gaucher disease (nGD), the exact mechanism underlying neurodegeneration in nGD remains unclear. In this study, we used two induced pluripotent stem cells (iPSCs)-derived neuronal cell lines acquired from two type-3 GD patients (GD3-1 and GD3-2) to investigate the mechanisms underlying nGD by biochemical analyses. These iPSCs-derived neuronal cells from GD3-1 and GD3-2 exhibit an impairment in endoplasmic reticulum (ER) calcium homeostasis and an increase in unfolded protein response markers (BiP and CHOP), indicating the presence of ER stress in nGD. A significant increase in the BAX/BCL-2 ratio and an increase in Annexin V-positive cells demonstrate a notable increase in apoptotic cell death in GD iPSCs-derived neurons, suggesting downstream signaling after an increase in the unfolded protein response. Our study involves the establishment of iPSCs-derived neuronal models for GD and proposes a possible mechanism underlying nGD. This mechanism involves the activation of ER stress and the unfolded protein response, ultimately leading to apoptotic cell death in neurons.

The molecular mechanisms underlying gut microbiota-miRNA interaction in metabolic disorders

Metabolic disorders are a major global health problem. Gut microbiota not only affect host metabolism through metabolites, inflammatory processes, and microbial-derived extracellular vesicles, but they also modulate the host microRNA, which may impact the host metabolism. Hence, the underlying mechanisms between gut microbiota-microRNA interaction can potentially be a novel alternative strategy for treating metabolic disorders. This review aims to give an update on the latest evidence and current knowledge of the underlying mechanisms of gut microbiota-miRNA interaction, focusing on metabolic homeostasis. Gut microbiota mainly communicate with host microRNA through lipopolysaccharide and secondary microbial metabolites. These signalling messengers circulate around the metabolic organs and modify gene expression through microRNA interference. Interestingly, while intestinal microRNAs play a vital role in both intestinal barrier and gut microbiota homeostasis, the presence of gut microbiota is also required for the proper functioning of intestinal microRNAs, suggesting a cooperative mechanism in intestinal health. Although the correlations between gut microbiota and microRNA have been observed in both mice and humans, a causal relationship should be confirmed. Moreover, further investigation is needed to provide more evidence of a gut microbiota-microRNA interaction to support the possibility of using that axis as a novel therapeutic target to treat metabolic disorders.

The Benefits of Anthocyanins against Obesity-Induced Inflammation

Obesity has become a serious public health epidemic because of its associations with chronic conditions such as type 2 diabetes mellitus, hypertension, cardiovascular disease, and cancer. Obesity triggers inflammation marked by the secretion of low-grade inflammatory cytokines including interleukin-6, C-reactive protein, and tumor necrosis factor-α, leading to a condition known as “meta-inflammation”. Currently, there is great interest in studying the treatment of obesity with food-derived bioactive compounds, which have low toxicity and no severe adverse events compared with pharmacotherapeutic agents. Here, we reviewed the beneficial effects of the bioactive compounds known as anthocyanins on obesity-induced inflammation. Foods rich in anthocyanins include tart cherries, red raspberries, black soybeans, blueberries, sweet cherries, strawberries and Queen Garnet plums. These anthocyanin-rich foods have been evaluated in cell culture, animal, and clinical studies, and found to be beneficial for health, reportedly reducing inflammatory markers. One factor in the development of obesity-related inflammation may be dysbiosis of the gut microbiome. Therefore, we focused this review on the in vitro and in vivo effects of anthocyanins on inflammation and the gut microbiota in obesity.

Lowering of lysophosphatidylcholines in ovariectomized rats by Curcuma comosa

Decline of ovarian function in menopausal women increases metabolic disease risk. Curcuma comosa extract and its major compound, (3R)-1,7-diphenyl-(4E,6E)-4,6-heptadien-3-ol (DPHD), improved estrogen-deficient ovariectomized (OVX) rat metabolic disturbances. However, information on their effects on metabolites is limited. Here, we investigated the impacts of C. comosa ethanol extract and DPHD on 12-week-old OVX rat metabolic disturbances, emphasizing the less hydrophobic metabolites. Metabolomics analysis of OVX rat serum showed a marked increase compared to sham-operated rat (SHAM) in levels of lysophosphatidylcholines (lysoPCs), particularly lysoPC (18:0) and lysoPC (16:0), and of arachidonic acid (AA), metabolites associated with inflammation. OVX rat elevated lysoPCs and AA levels reverted to SHAM levels following treatments with C. comosa ethanol extract and DPHD. Overall, our studies demonstrate the effect of C. comosa extract in ameliorating the metabolic disturbances caused by ovariectomy, and the elevated levels of bioactive lipid metabolites, lysoPCs and AA, may serve as potential biomarkers of menopausal metabolic disturbances.

Ex vivo expansion and functional activity preservation of adult hematopoietic stem cells by a diarylheptanoid from Curcuma comosa

Hematopoietic stem cells (HSCs, CD34+ cells) have shown therapeutic efficacy for transplantation in various hematological disorders. However, a large quantity of HSCs is required for transplantation. Therefore, strategies to increase HSC numbers and preserve HSC functions through ex vivo culture are critically required. Here, we report that expansion medium supplemented with ASPP 049, a diarylheptanoid isolated from Curcuma comosa, and a cocktail of cytokines markedly increased numbers of adult CD34+ cells. Interestingly, phenotypically defined primitive HSCs (CD34+CD38-CD90+) were significantly increased under ASPP 049 treatment relative to control. ASPP 049 treatment also improved two functional properties of HSCs, as evidenced by an increased number of CD34+CD38- cells in secondary culture (self-renewal) and the growth of colony-forming units as assessed by colony formation assay (multilineage differentiation). Transplantation of cultured CD34+ cells into immunodeficient mice demonstrated the long-term reconstitution and differentiation ability of ASPP 049-expanded cells. RNA sequencing and KEGG analysis revealed that Hippo signaling was the most likely pathway involved in the effects of ASPP 049. These results suggest that ASPP 049 improved ex vivo expansion and functional preservation of expanded HSCs. Our findings provide a rationale for the use of ASPP 049 to grow HSCs prior to hematological disease treatment.

Andrographolide Reduces Lipid Droplet Accumulation in Adipocytes Derived from Human Bone Marrow Mesenchymal Stem Cells by Suppressing Regulators of Adipogenesis

Obesity has become a major public health concern; so, a strategy to prevent or reduce obesity is a priority. The inhibition of lipid droplet accumulation and adipogenesis process provides a target for the treatment of obesity. Herein, the effect of andrographolide (AP) on lipid accumulation in adipocytes derived from human bone marrow mesenchymal stem cells (hBM-MSCs) was examined. AP at concentrations of 1, 2.5, 5, and 10 μM reduced lipid droplet accumulation in the adipocytes by suppressing the adipogenic differentiation of hBM-MSCs. Concurrently, the expressions of adipogenic marker genes and the level of adipokines secreted by adipocytes were suppressed. Gene screening analysis showed a negative regulation of genes involved in the adipogenesis process. In conclusion, we demonstrated for the first time an antilipid accumulation in adipocytes from hBM-MSCs by AP. The compound may potentially be a novel therapeutic agent for the treatment of obesity as well as obesity-related diseases.

Inhibition of Adipogenic Differentiation of Human Bone Marrow-Derived Mesenchymal Stem Cells by a Phytoestrogen Diarylheptanoid from Curcuma comosa

We investigated the effect of a phytoestrogen, (3R)-1,7-diphenyl-(4E,6E)-4,6-heptadien-3-ol (DPHD), from Curcuma comosa Roxb. (Zingiberaceae family) on the adipogenic differentiation of mesenchymal progenitors, human bone marrow-derived mesenchymal stem cells (hBMSCs). DPHD inhibited adipocyte differentiation of hBMSCs by suppressing the expression of genes involved in adipogenesis. DPHD at concentrations of 0.1, 1, and 10 μM significantly decreased triglyceride accumulation in hBMSCs to 7.1 ± 0.2, 6.3 ± 0.4, and 4.9 ± 0.2 mg/dL, respectively, compared to the nontreated control (10.1 ± 0.9 mg/dL) (p < 0.01). Based on gene expression profiling, DPHD increased the expression of several genes involved in the Wnt/β-catenin signaling pathway, a negative regulator of adipocyte differentiation in hBMSCs. DPHD also increased the levels of essential signaling proteins which are extracellular signal-regulated kinases 1 and 2 (ERK1/2) and glycogen synthase kinase 3 beta (GSK-3β) that link estrogen receptor (ER) signaling to Wnt/β-catenin signaling. In conclusion, DPHD exhibited the anti-adipogenic effect in hBMSCs by suppression of adipogenic markers in hBMSCs through the activation of ER and Wnt/β catenin signaling pathways. This finding suggests the potential role of DPHD in preventing bone marrow adiposity which is one of the major factors that exacerbates osteoporosis in postmenopause.

Curcuma comosa reduces visceral adipose tissue and improves dyslipidemia in ovariectomized rats

ETHNOPHARMACOLOGICAL RELEVANCE

Curcuma comosa Roxb. (C. comosa) or Wan chak motluk Zingiberaceae family, is widely used in Thai traditional medicine for treatment of gynecological problems as well as relief of postmenopausal symptoms. Since C. comosa contains phytoestrogen and causes lipid lowering effect by an unknown mechanism, we investigated its effect on adiposity and lipid metabolism in estrogen-deprived rats.

MATERIALS AND METHODS

Adult female rats were ovariectomized (OVX) and received daily doses of either a phytoestrogen from C. comosa [(3R)-1,7-diphenyl-(4E,6E)-4,6-heptadien-3-ol; DPHD], C. comosa extract, or estrogen (17β-estradiol; E2) for 12 weeks. Adipose tissue mass, serum levels of lipids and adipokines were determined. In addition, genes and proteins involved in lipid synthesis and fatty acid oxidation in visceral adipose tissue were analyzed.

RESULTS

Ovariectomy for 12 weeks elevated level of serum lipids and increased visceral fat mass and adipocyte size. These alterations were accompanied with the up-regulation of lipogenic mRNA and protein expressions including LXR-α, SREBP1c and their downstream targets. OVX rats showed decrease in proteins involved in fatty acid oxidation including AMPK-α and PPAR-α in adipose tissue, as well as alteration of adipokines; leptin and adiponectin. Treatments with E2, DPHD or C. comosa extract in OVX rats prevented an increase in adiposity, down-regulated lipogenic genes and proteins with marked increases in the protein levels of AMPK-α and PPAR-α. These findings indicated that their lipid lowering effects were mediated via the suppression of lipid synthesis in concert with an increase in fatty acid oxidation.

CONCLUSIONS

C. comosa exerts a lipid lowering effect in the estrogen deficient rats through the modulations of lipid synthesis and AMPK-α activity in adipose tissues, supporting the use of this plant for health promotion in the post-menopausal women.

Adrenocorticotropic hormone and 1,25-dihydroxyvitamin D3 enhance human osteogenesis in vitro by synergistically accelerating the expression of bone-specific genes

To improve definition of the physical and hormonal support of bone formation, we studied differentiation of human osteoblasts in vitro at varying combinations of ACTH, 1α,25-dihydroxyvitamin D₃ (1,25(OH)₂D), and extracellular calcium, with and without added cortisol. Bone mineralization, alkaline phosphatase activity, and osteoblast-specific markers RunX2, osterix, and collagen I increased with 10 pM ACTH, 10 nM 1,25(OH)₂D, or at 2 mM calcium with important synergistic activity of combinations of any of these stimuli. Signals induced by ACTH at 10-30 min included cAMP, TGF-β, and Erk1/2 phosphorylation. Affymetrix gene expression analysis showed that 2 h treatment of ACTH or 1,25(OH)₂D increased the expression of bone regulating and structural mRNAs, including collagen I, biglycan, the vitamin D receptor, and TGF-β. Accelerating expression of these bone-specific genes was confirmed by quantitative PCR. Expression of 1,25(OH)₂D 1α-hydroxylase (1α-hydroxylase) increased with 1,25(OH)₂D, ACTH, and extracellular calcium from 0.5 to 2 mM. Unlike renal 1α-hydroxylase, in osteoblasts, 1α-hydroxylase activity is independent of parathyroid hormone. In keeping with calcium responsivity, calcium-sensing receptor RNA and protein increased with 10 nM ACTH or 1,25(OH)₂D. Inclusion of 200 nM cortisol or 10 nM ACTH in differentiation media blunted osteoblasts alkaline phosphatase response to 1,25(OH)₂D and calcium. Our results point to the importance of ACTH in bone maintenance and that extra skeletal (renal) 1,25(OH)₂D is required for bone mineralization despite 1α-hydroxylase expression by osteoblasts.