SUMMARY Of all known cultured stem cell types, pluripotent stem cells (PSCs) sit atop the landscape of developmental potency and are characterized by their ability to generate all cell types of an adult organism. However, PSCs show limited contribution to the extraembryonic placental tissues in vivo. Here, we show that a chemical cocktail enables the derivation of stem cells with unique functional and molecular features from mice and humans, designated as extended pluripotent stem (EPS) cells, which are capable of chimerizing both embryonic and extraembryonic tissues. Notably, a single mouse EPS cell shows widespread chimeric contribution to both embryonic and extraembryonic lineages in vivo and permits generating single-EPS-cell-derived mice by tetraploid complementation. Furthermore, human EPS cells exhibit interspecies chimeric competency in mouse conceptuses. Our findings constitute a first step toward capturing pluripotent stem cells with extraembryonic developmental potentials in culture and open new avenues for basic and translational research.

Induced pluripotent stem (iPS) cells can be generated from somatic cells by transduction with several transcription factors in mouse and human. However, direct reprogramming in other species has not been reported. Here, we generated monkey iPS cells by retrovirus-mediated introduction of monkey transcription factors OCT4, SOX2, KLF4, and c-MYC.

SUMMARY The reprogramming factors that induce pluripotency have been identified primarily from embryonic stem cell (ESC)-enriched, pluripotency-associated factors. Here we report that during mouse somatic cell reprogramming, pluripotency can be induced with lineage specifiers that are pluripotency rivals to suppress ESC identity, most of which are not enriched in ESCs. We found that OCT4 and SOX2, the core regulators of pluripotency, can be replaced by lineage specifiers that are involved in mesendodermal (ME) specification and in ectodermal (ECT) specification, respectively. OCT4 and its substitutes attenuated the elevated expression of a group of ECT genes whereas SOX2 and its substitutes curtailed a group of ME genes during reprogramming. Surprisingly, the two counteracting lineage specifiers can synergistically induce pluripotency in the absence of both OCT4 and SOX2. Our study suggests a “seesaw model,” in which a balance that is established using pluripotency factors and/or counteracting lineage specifiers can facilitate reprogramming.

Extrinsic BMP and LIF signaling collaboratively maintain mouse embryonic stem cell (ESC) pluripotency, whereas appropriate ERK activity is essential for ESC fate commitment. However, how the extrinsic signals restrain appropriate ERK activity remains elusive. Here, we show that, whereas LIF sustains relatively high ERK activity, BMP4 can steadily attenuate ERK activity by upregulating ERK-specific dual-specificity phosphatase 9 (DUSP9). This upregulation requires Smad1/5 and Smad4 and specifically occurs to DUSP9, but not other DUSPs, and only in ESCs. Through DUSP9-mediated inhibition of ERK activity, BMP signaling reinforces the self-renewal status of mouse ESCs together with LIF. Upon LIF withdrawal, ESCs spontaneously undergo neural differentiation, during which process DUSP9 can partially mediate BMP inhibition on neural commitment. Collectively, our findings identify DUSP9 as a critical mediator of BMP signaling to control appropriate ERK activity critical for ESC fate determination.

Highlights d Kindlin-2 mediates MOB1 proteasomal degradation by its E3 ligase praja2 d Kindlin-2 inhibits phosphorylation of YAP by promoting degradation of MOB1 d Kindlin-2 depletion activates the Hippo pathway and alleviates UUO-induced renal fibrosis d Long-lasting Kindlin-2 siRNA shows a therapeutic value in UUO-induced renal fibrosis

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Edited by Dietmar J. Manstein Keywords:Kindlin-2 a-Actinin-2The Z-disc Cardiac structure a b s t r a c t Kindlin-2, as an integrin-interacting protein, was known to be required for the maintenance of cardiac structure and function in zebrafish. However, the mechanism remains unclear. We found that Kindlin-2 interacts and colocalizes with a-actinin-2 at the Z-disc of mouse cardiac muscles and there Kindlin-2 also interacts with b1 integrin. Knockdown of Kindlin-2 influences the association of b1 integrin with a-actinin-2 and disrupts the structure of the Z-disc and leads to cardiac dysfunction. Our data indicated that Kindlin-2 is a novel a-actinin-2-interacting protein and plays an important role in the regulation of cardiac structure and function.

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