Mesenchymal Stem Cell Therapy: a1 antitrypsin deficiency

描述（由申请人提供）： α-1-抗胰蛋白酶（α 1AT）是一种血浆蛋白，在肝脏中产生，抑制弹性蛋白酶，α 1AT缺乏症是一种常染色体隐性遗传疾病，在美国影响约105个个体。α 1AT缺乏症的肝损伤是由保留在肝细胞内质网（ER）内的突变α 1AT的肝毒性作用引起的，而肺气肿是由对肺实质中弹性组织的不受抑制的蛋白水解损伤引起的。原位肝移植是α 1AT介导的肝病的唯一治愈性疗法。如果有可靠的肝细胞来源，它们可以替代20 - 25%的宿主肝脏，使血浆中α 1AT水平升高到10 μ M以上，并防止由于α 1AT缺乏引起的肺毒性。我们已经确定了多能成体祖细胞，或MAPC，可以从人类，小鼠和大鼠骨髓（BM）培养。单个MAPC在体外可分化为中胚层、神经外胚层样细胞和功能性肝细胞样细胞。MAPC在IV、IM或SQ输注时不形成肿瘤，但响应于局部线索而分化成造血细胞和肺、肠和肝的上皮。为了使MAPC衍生的肝细胞适用于α 1AT或其他肝脏疾病的治疗，需要更好地表征体外分化过程。此外，我们需要证明MAPC衍生的细胞在体内的功能与肝细胞相似。我们提出了三个目标，以确定MAPC衍生的肝细胞是否可能是治疗α 1AT缺陷介导的肺部和/或肝脏疾病的细胞来源。在SA 1中的研究将进一步证明，肝细胞样细胞可以从骨髓源性MAPC中产生，并开发方法来选择培养期间产生的肝细胞的祖细胞/前体细胞。选择这样的祖细胞将用于两个目的：表征从多能成体干细胞到肝细胞的分化，以及产生用于肝病中有效移植的潜在细胞来源。SA 2中描述的评估球状体培养物中成熟肝细胞所有功能的研究应有助于证实BM MAPC生成的肝细胞与原代肝细胞相似。在SA3中的研究将确定MAPC本身、MAPC衍生的肝细胞祖细胞或成熟肝细胞是否可以在肝细胞死亡的情况下以及在肝功能异常但无肝细胞死亡的情况下在体内恢复肝功能。这将为未来的研究奠定基础，测试MAPC或MAPC衍生的肝细胞祖细胞/肝细胞是否可以作为治疗α 1AT的合适细胞来源，α 1AT是一种与肺损伤和/或肝功能衰竭相关的单基因缺陷。

DESCRIPTION (provided by applicant): Alpha-l-antitrypsin (alpha1AT) is a plasma protein, produced in the liver that inhibits elastase, alpha1AT-deficiency is an autosomal recessive disorder that affects approximately 105 individuals in the US. Liver injury in alpha1AT-deficiency is caused by the hepatotoxic effects of mutant alpha1AT retained within the endoplasmic reticulum (ER) of hepatocytes, and emphysema by uninhibited proteolytic damage to elastic tissue in the lung parenchyma. Orthoptic liver transplantation is the only curative therapy for alpha1AT-mediated liver disease. If a reliable source of hepatocytes were available, they could conceivably be used to replace 20-25% of the host liver, elevating plasma levels of alpha1AT to greater than 10 muM, and preventing pulmonary toxicity due to alpha1AT-deficiency. We have identified multipotent adult progenitor cells, or MAPC, that can be cultured from human, mouse and rat bone marrow (BM). Single MAPC differentiate into mesodermal, neuroectoderm-like cells and functioning hepatocyte-like cells in vitro. MAPC do not form tumors when infused IV, IM or SQ, but differentiate in response to local cues into hematopoietic cells and epithelium of lung, intestine and liver. For MAPC derived hepatocytes to be suitable for therapy of alpha1AT, or other liver disorders, better characterization of the in vitro differentiation process will be needed. In addition, we will need to demonstrate that MAPC-derived cells function like hepatocytes in vivo. We propose three aims to determine whether MAPC-derived hepatocytes may be a source of cells to treat alpha1AT-deficiency mediated pulmonary and/or liver disease. Studies in SA1 will further demonstrate that hepatocyte like cells can be generated from bone marrow derived MAPC, and develop methods to select progenitors/precursors for hepatocytes generated during culture. Selection of such progenitors will serve two purposes: characterization of differentiation from pluripotent adult stem cells to hepatocytes, and generation of a potential source of cells for effective transplantation in liver disease. Studies described in SA2 that will assess all functions of mature hepatocytes in spheroid cultures should help confirm that hepatocytes generated from BM MAPC are similar to hepatocytes derived from primary liver. Studies in SA3 will establish whether MAPC themselves, MAPC-derived hepatocyte progenitors or mature hepatocytes can restore liver function in vivo, in the setting of hepatocyte cell death and in the setting of abnormal liver function but without liver cell death. This should lay the groundwork for future studies testing whether MAPC or MAPC-derived hepatocyte progenitors/hepatocytes can serve as a suitable source of cells for therapy of alpha1AT, a single gene defect associated with lung damage and/or liver failure.