Caspase-3 Regulates YAP-Dependent Cell Proliferation and Organ Size.

Apoptosis culminates in the activation of caspase-3, which plays an important role in implementing the cell death program. Here, we reveal a non-apoptotic role of caspase-3 as a key regulator of cell proliferation and organ size. Caspase-3 is specifically activated in the proliferating cells of the sebaceous gland, but does not instruct cell elimination. Deletion or chemical inhibition of caspase-3 diminishes cell proliferation, decreases cell number and reduces sebaceous gland size in vivo. Exploring the underlying mechanism, we demonstrate that α-catenin is cleaved by caspase-3, thus facilitating the activation and nuclear translocation of yes-associated protein (YAP), a vital regulator of organ size. Accordingly, activation of caspase-3 leads to YAP-dependent organ size augmentation. Finally, we show that X-linked inhibitor of apoptosis protein (XIAP) serves as an endogenous feedback antagonist for the caspase-3/YAP signaling module. Taken together, we report here a molecular mechanism wherein the apoptotic machinery is refocused to regulate cell proliferation and orchestrate organ size.

Lgr5 marks stem/progenitor cells contributing to epithelial and muscle development in the mouse esophagus.

The existence and function of Lgr5+ cells within the developing esophagus remains unknown. Here, we document multiple discrete Lgr5+ populations in the developing mouse esophagus, predominantly within nascent epithelial and external muscle layers. Lgr5 expression initially emerges in the developing proximal embryonic epithelium, but progressively extends distally and persists within the distal epithelium of neonates. Fate mapping and ablation analyses reveal a long-term contribution of epithelial Lgr5+ cells to esophageal organogenesis. Additionally, Lgr5-expressing cells are present in the developing external muscle layer, particularly during the development of the striated component. Fate mapping reveals a significant contribution of these embryonic Lgr5+ cells to the adult muscle layer. Embryonic Lgr5+ epithelial cells are also found to be important for regulating epithelial development, serving as a key source of Wnt6, among other ligands, to promote epithelial cell proliferation and formation of epithelial layers. These findings significantly enhance our understanding of esophageal development and shed light on the involvement of Lgr5+ stem/progenitor cells during organogenesis. Importantly, this study lays the foundation for investigating esophageal diseases related to the Lgr5+ stem/progenitor cell pool.

[Opatija study: observation of hemodialysis patients and titration of CERA dose just switched from another erythropoiesis stimulating agent]. / Istrazivanje OPATIJA: Promatranje hemodijaliziranih bolesnika i titriranje doze lijeka CERA na koji su bolesnici prebaceni s drugih lijekova koji stimuliraju eritropoezu.

INTRODUCTION: Anemia is a well-documented consequence of chronic kidney disease, its frequency increases with the progression of renal failure and occurs in up to 95% of patients with end stage renal disease (ESRD). Erythropoietin stimulating agents (ESAs) have become the standard of care in the treatment of renal anemia. The use of methoxy polyethylene glycol-epoetin beta, continuous erythropoietin receptor activator, represents an important benefit in clinical practice. AIM: The aim of the OPATIJA study was to compare the efficacy and safety of maintaining hemoglobin levels in dialysis patients and to assess its variability in a parallel-group design. Patients were randomly assigned to receive methoxy polyethylene glycolepoetin beta once monthly in "normal" dose conversion according to the label of record or "low" or "alternative" dose conversion widely spread according to previous ESA doses. SUBJECTS AND METHODS: A total of 79 patients were included in the study. The patients who had undergone continuous maintenance intravenous ESA therapy were divided into two parallel groups: group 1 including 36 patients directly switched to CERA according to the manufacturer recommended dosage; and group 2 including 43 patients that were switched by using "low" or "alternative" dose conversion widely spread according to previous ESA doses. During the 18-month period, each patient's anemia parameters, i.e. hemoglobin level, serum iron concentration, TSAT and ferritin, were monitored at intervals not longer than two months. According to hemoglobin levels, the dosage of CERA was adjusted if needed along with iron supplementation. RESULTS: At the end of the study, the two groups consisted of 51 patients: 26 of those treated with the recommended dose of CERA and 25 treated with the alternative dose. In the normal conversion group, the mean hemoglobin level during the course of the study was 104.41 g/L with the mean monthly dose of 104.33 mcg CERA. In the alternative conversion group, the mean hemoglobin level during the course of the study was 105.33 g/L with the mean monthly dose'of 113.08 mcg CERA. In the alternative conversion group, 33% of patients had Hb levels in the tight recommended range of 110-120 g/L. In 30% of patients, Hb levels were 100-110 g/L, in 29% less than 100 g/L, and in 8% more than 120 g/L. The mean Hb levels at the beginning and the end of the study did not differ significantly, except for the patient group with Hb levels >120 g/L, where 7% of patients with recommended dosing and none of the patients from the alternative dosing group had such levels (P=0.017). Hemoglobin variability higher than 10 and 20 g/L was recorded in both groups, but less frequently in the alternative CERA dosing group. CONCLUSION: Both treatments with the recommended and alternative conversion dosing achieved and maintained target hemoglobin level. Study results confirmed the need of individualized approach in the treatment of anemia in ESRD patients receiving hemodialysis, resulting in less potentially harmful hemoglobin variability.

Isolation of Stem Cells and Progenitors from Mouse Epidermis.

The epidermis consists of several distinct compartments including the interfollicular epidermis (IFE), sweat glands, sebaceous glands (SGs), and the hair follicle (HF). While the IFE and SGs are in a constant state of self-renewal, the HF cycles between phases of growth, destruction, and rest. The hair follicle stem cells (HFSCs) that fuel this perpetual cycle have been well described and are located in a niche termed the bulge. These bulge SCs express markers such as CD34 and Keratin 15 (K15), enabling the isolation of these cells. Here, we describe a powerful method for isolating HFSCs and epidermal progenitors from mouse skin utilizing fluorescence activated cell-sorting (FACS). Upon isolation, cells can be expanded and utilized in various in vivo and in vitro models aimed at studying the function of these unique cells. © 2017 by John Wiley & Sons, Inc.

Isolating Hair Follicle Stem Cells and Epidermal Keratinocytes from Dorsal Mouse Skin.

The hair follicle (HF) is an ideal system for studying the biology and regulation of adult stem cells (SCs). This dynamic mini organ is replenished by distinct pools of SCs, which are located in the permanent portion of the HF, a region known as the bulge. These multipotent bulge SCs were initially identified as slow cycling label retaining cells; however, their isolation has been made feasible after identification of specific cell markers, such as CD34 and keratin 15 (K15). Here, we describe a robust method for isolating bulge SCs and epidermal keratinocytes from mouse HFs utilizing fluorescence activated cell-sorting (FACS) technology. Isolated hair follicle SCs (HFSCs) can be utilized in various in vivo grafting models and are a valuable in vitro model for studying the mechanisms that govern multipotency, quiescence and activation.