Radiating diversification and niche conservatism jointly shape the inverse latitudinal diversity gradient of Potentilla L. (Rosaceae).

BACKGROUND: The latitudinal diversity gradient (LDG), characterized by an increase in species richness from the poles to the equator, is one of the most pervasive biological patterns. However, inverse LDGs, in which species richness peaks in extratropical regions, are also found in some lineages and their causes remain unclear. Here, we test the roles of evolutionary time, diversification rates, and niche conservatism in explaining the inverse LDG of Potentilla (ca. 500 species). We compiled the global distributions of ~ 90% of Potentilla species, and reconstructed a robust phylogenetic framework based on whole-plastome sequences. Next, we analyzed the divergence time, ancestral area, diversification rate, and ancestral niche to investigate the macroevolutionary history of Potentilla. RESULTS: The genus originated in the Qinghai-Tibet Plateau during the late Eocene and gradually spread to other regions of the Northern Hemisphere posterior to the late Miocene. Rapid cooling after the late Pliocene promoted the radiating diversification of Potentilla. The polyploidization, as well as some cold-adaptive morphological innovations, enhanced the adaptation of Potentilla species to the cold environment. Ancestral niche reconstruction suggests that Potentilla likely originated in a relatively cool environment. The species richness peaks at approximately 45 °N, a region characterized by high diversification rates, and the environmental conditions are similar to the ancestral climate niche. Evolutionary time was not significantly correlated with species richness in the latitudinal gradient. CONCLUSIONS: Our results suggest that the elevated diversification rates in middle latitude regions and the conservatism in thermal niches jointly determined the inverse LDG in Potentilla. This study highlights the importance of integrating evolutionary and ecological approaches to explain the diversity pattern of biological groups on a global scale.

3D Printing of a Vascularized Mini-Liver Based on the Size-Dependent Functional Enhancements of Cell Spheroids for Rescue of Liver Failure.

The emerging stem cell-derived hepatocyte-like cells (HLCs) are the alternative cell sources of hepatocytes for treatment of highly lethal acute liver failure (ALF). However, the hostile local environment and the immature cell differentiation may compromise their therapeutic efficacy. To this end, human adipose-derived mesenchymal stromal/stem cells (hASCs) are engineered into different-sized multicellular spheroids and co-cultured with 3D coaxially and hexagonally patterned human umbilical vein endothelial cells (HUVECs) in a liver lobule-like manner to enhance their hepatic differentiation efficiency. It is found that small-sized hASC spheroids, with a diameter of ≈50 µm, show superior pro-angiogenic effects and hepatic differentiation compared to the other counterparts. The size-dependent functional enhancements are mediated by the Wnt signaling pathway. Meanwhile, co-culture of hASCs with HUVECs, at a HUVECs/hASCs seeding density ratio of 2:1, distinctly promotes hepatic differentiation and vascularization both in vitro and in vivo, especially when endothelial cells are patterned into hollow hexagons. After subcutaneous implantation, the mini-liver, consisting of HLC spheroids and 3D-printed interconnected vasculatures, can effectively improve liver regeneration in two ALF animal models through amelioration of local oxidative stress and inflammation, reduction of liver necrosis, as well as increase of cell proliferation, thereby showing great promise for clinical translation.

Microfluidic Fabrication of MicroRNA-Induced Hepatocyte-Like Cells/Human Umbilical Vein Endothelial Cells-Laden Microgels for Acute Liver Failure Treatment.

Acute liver failure (ALF) is a critical life-threatening disease that occurs due to a rapid loss in hepatocyte functions. Hepatocyte transplantation holds great potential for ALF treatment, as it rapidly supports liver biofunctions and enhances liver regeneration. However, hepatocyte transplantation is still limited by renewable and ongoing cell sources. In addition, intravenously injected hepatocytes are primarily trapped in the lungs and have limited efficacy because of the rapid clearance in vivo. Here, we designed a Y-shaped DNA nanostructure to deliver microRNA-122 (Y-miR122), which could induce the hepatic differentiation and maturation of human mesenchymal stem cells. mRNA sequencing analysis revealed that the Y-miR122 promoted important hepatic biofunctions of the induced hepatocyte-like cells including fat and lipid metabolism, drug metabolism, and liver development. To further improve hepatocyte transplantation efficiency and therapeutic effects in ALF treatment, we fabricated protective microgels for the delivery of Y-miR122-induced hepatocyte-like cells based on droplet microfluidic technology. When cocultured with human umbilical vein endothelial cells in microgels, the hepatocyte-like cells exhibited an increase in hepatocyte-associated functions, including albumin secretion and cytochrome P450 activity. Notably, upon transplantation into the ALF mouse model, the multiple cell-laden microgels effectively induced the restoration of liver function and enhanced liver regeneration. Overall, this study presents an efficient approach from the generation of hepatocyte-like cells to hepatocyte transplantation in ALF therapy.

MicroRNA-122-functionalized DNA tetrahedron stimulate hepatic differentiation of human mesenchymal stem cells for acute liver failure therapy.

As the most abundant liver-specific microRNA, microRNA-122 (miR122) played a crucial role in the differentiation of stem cells into hepatocytes. However, highly efficient miR122 delivery still confronts challenges including poor cellular uptake and easy biodegradation. Herein, we for the first time demonstrated that the tetrahedral DNA (TDN) nanoplatform had great potential in inducing the differentiation of human mesenchymal stem cells (hMSCs) into functional hepatocyte-like cells (HLCs) by transferring the liver-specific miR122 to hMSCs efficiently without any extrinsic factors. As compared with miR122, miR122-functionalized TDN (TDN-miR122) could significantly up-regulate the protein expression levels of mature hepatocyte markers and hepatocyte-specific marker genes in hMSCs, indicating that TDN-miR122 could particularly activate the hepatocyte-specific properties of hMSCs for developing cell-based therapies in vitro. The transcriptomic analysis further indicated the potential mechanism that TDN-miR122 assisted hMSCs differentiated into functional HLCs. The TDN-miR122-hMSCs exhibited hepatic cell morphology phenotype, significantly up-regulated specific hepatocyte genes and hepatic biofunctions in comparison with the undifferentiated MSCs. Preclinical in vivo transplantation appeared that TDN-miR122-hMSCs in combination with or without TDN could efficiently rescue acute liver failure injury through hepatocyte function supplement, anti-apoptosis, cellular proliferation promotion, and anti-inflammatory. Collectively, our findings may provide a new and facile approach for hepatic differentiation of hMSCs for acute liver failure therapy. Further large animal model explorations are needed to study their potential in clinical translation in the future.

Label-free detection of biomarker alpha fetoprotein in serum by ssDNA aptamer functionalized magnetic nanoparticles.

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors in the clinic, with the characteristics of occult onset, rapid progression, and high degree of malignancy. Alpha fetoprotein (AFP) is the most important biomarker of HCC, which is widely used in early screening, diagnosis, and prognosis observation. A series of immunoassays have been developed and frequently used in the detection of AFP based on antibodies. Unfortunately, the shortcomings of antibodies, such as thermal unstable and fluctuant activity by batches, lead to the inaccuracy in the detection of AFP. In this study, aptamers instead of antibodies were adopted as the specific recognition element for AFP, aiming to seek an alternative strategy to immunoassays. An AFP-specific ssDNA aptamer was grafted to magnetic nanoparticles (Fe3O4@SiO2) via avidin-biotin interaction, and the resultant aptamer functionalized magnetic nanoparticles (Ap-MNPs) were adequately characterized and tested. The Ap-MNPs in solution exhibited a fast response to the outer magnetic field, and can be completely separated in several minutes. It was found that Ap-MNPs have good specificity to the target AFP, as the recovery of AFP (87.0%) was much higher than the competitive proteins IgG (38.9%), HSA (18.5%), and FIB (11.4%). A convenient and efficient label-free detection method of AFP in serum was developed based on Ap-MNPs in combination with high-performance liquid chromatography. The linearity of this method was over a range of 1-50 µg ml-1 with a correlation coefficient of 0.9999, and the limit of detection was 0.27 µg ml-1. This study indicated that aptamers are an ideal tool for the recognition and detection of biomarkers, and thus will find wide applications in clinical practice.

Graphene oxide-based magnetic nanocomposites for the delivery of melittin to cervical cancer HeLa cells.

Melittin (MEL), the primary active component of bee venom, has recently emerged as a promising cancer chemotherapeutic agent. However, the instability and rapid degradation of MEL is a significant challenge in practical therapeutic applications. In the present study, graphene oxide (GO)-based magnetic nanocomposites (PEG-GO-Fe3O4) were prepared and adopted as the drug delivery vehicles of MEL, and the anticancer effects of PEG-GO-Fe3O4/MEL complexes on human cervical cancer HeLa cells were studied. PEG-GO-Fe3O4 exhibited a series of unique physical and chemical properties resulting in multiple interactions with MEL, and ultimately the release of MEL. In vitro experiments showed that PEG-GO-Fe3O4/MEL not only distinctly enhanced the inhibition effect on HeLa cells, but also induced pore formation in the cell membrane that ultimately led to cell lysis. In this newly developed drug delivery system, PEGylated GO plays the role of a MEL protector while Fe3O4 nanoparticles act as magnetic responders; therefore active MEL can be released over a long period of time (up to 72 h) and maintain its inhibition effect on HeLa cells.