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Death from chronic lung disease is increasing and chronic obstructive pulmonary disease has become the third leading cause of death in the United States in the past decade. Both chronic and acute lung diseases disproportionately affect elderly individuals, making it likely that these diseases will become more frequent and severe as the worldwide population ages. Chronic lung diseases are associated with substantial morbidity, frequently resulting in exercise limiting dyspnea, immobilization, and isolation. Therefore, effective strategies to prevent or treat lung disease are likely to increase healthspan as well as life span. This review summarizes the findings of a joint workshop sponsored by the NIA and NHLBI that brought together investigators focused on aging and lung biology. These investigators encouraged the use of genetic systems and aged animals in the study of lung disease and the development of integrative systems-based platforms that can dynamically incorporate data sets that describe the genomics, transcriptomics, epigenomics, metabolomics, and proteomics of the aging lung in health and disease. Further research was recommended to integrate benchmark biological hallmarks of aging in the lung with the pathobiology of acute and chronic lung diseases with divergent pathologies for which advanced age is the most important risk factor.

The proinflammatory cytokine TNF-[alpha] exerts its pleiotropic functions through activation of multiple downstream effectors, including JNK1. Yet, the underlying regulatory mechanism is incompletely understood. Here, we report that the transcription factor Myc-interacting zinc-finger protein 1 (Miz1) selectively suppresses TNF-[alpha]-induced JNK1 activation and cell death independently of its transcription activity. Proteomics analysis and yeast two-hybrid screening reveal that Mizl is a JNK-associated protein. The TNF-[alpha]induced activation of JNK1 is augmented in Miz1-deficient mouse embryonic fibroblasts ([Miz1.sup.-/-] MEFs), but the augmentation is abrogated by reintroduction of Miz1 or its transcription-deficient mutant. The regulation by Miz1 is highly specific, because it regulates TNF-[alpha]-induced TRAF2 K63-linked polyubiquitination. Neither JNK1 activation by IL-1[beta] or UV nor TNF-[alpha]-induced activation of p38, ERK, or I[kappa]B kinase complex is affected by the loss of Miz1. The TNF-[alpha]-induced cell death also is accelerated in [Miz1.sup.-/-] MEFs. Upon TNF-[alpha] stimulation, Miz1 is degraded rapidly by the proteasome, relieving its suppression on JNK1 activation. Thus, our results show that in addition to being a transcription factor Miz1 acts as a signal-and pathway-specific modulator or regulator that specifically regulates TNF-[alpha]-induced JNK1 activation and cell death. doi/10.1073/pnas.0906328106

The p38 subgroup of the mitogen-activated protein kinase superfamily has four isoforms: p38[alpha], p38[beta], p38[delta] and p38[gamma]. Whereas p38[alpha] is involved in inflammation, proliferation, differentiation and apoptosis, the biological functions of p38[beta], p38[delta] and p38[gamma] are not understood completely. Many p38[alpha] inhibitors with diverse chemical structures and modes of protein interaction have been designed on the basis of their ability to compete with ATP for binding to p38[alpha]. Although some of these inhibitors show anti-inflammatory effects in animal models, they have repeatedly failed in clinical trials, highlighting the need for better approaches to inhibitor design. Here, we discuss alternative strategies that might lead to better p38 inhibitors, including non-ATP-competitive inhibitors and inhibitors that are targeted to other components of the signaling pathway.

Ligation of the asialoGM1 Pseudomonas aeruginosa pilin receptor has been demonstrated to induce IL-8 expression in airway epithelial cells via an NF-[kappa]B-dependent pathway. We examined the signaling pathways required for asialoGM1-mediated NF-[kappa]B activation in IB3 cells, a human bronchial epithelial cell line derived from a cystic fibrosis (CF) patient, and C-38 cells, the rescued cell line that expresses a functional CF transmembrane regulator. Ligation of the asialoGM1 receptor with specific antibody induced greater IL-8 expression in IB3 cells than C-38 cells, consistent with the greater density of asialoGM1 receptors in CF phenotype cells. AsialoGM1-mediated activation of NF-[kappa]B, I[kappa]B kinase (IKK), and ERK was also greater in IB3 cells. With the use of genetic inhibitors, we found that IKK-[beta] and NF-[kappa]B-inducing kinase are required for maximal NF-[kappa]B transactivation and transcription from the IL-8 promoter. Finally, although ERK activation was required for maximal asialoGM1-mediated IL-8 expression, inhibition of ERK signaling had no effect on IKK or NF-[kappa]B activation, suggesting that ERK regulates IL-8 expression in an NF-[kappa]B-independent manner. asialoGM1; extracellular signal-regulated kinase; I[kappa]B kinase; mitogen-activated protein kinase; mitogen-activated protein kinase/extracellular signal-regulated kinase kinase kinase; nuclear factor-[kappa]B-inducing kinase; tumor necrosis factor-[alpha]; cystic fibrosis

The transcription factor nuclear factor-[kappa]B (NF-[kappa]B) regulates expression of a variety of genes involved in immune responses, inflammation, proliferation, and programmed cell death (apoptosis). Here, we show that in rat neonatal ventricular cardiomyocytes, activation of NF-[kappa]B is involved in the hypertrophic response induced by myotrophin, a hypertrophic activator identified from spontaneously hypertensive rat heart and cardiomyopathic human hearts. Myotrophin treatment stimulated NF-[kappa]B nuclear translocation and transcriptional activity, accompanied by I[kappa]B-[alpha] phosphorylation and degradation. Consistently, myotrophin-induced NF-[kappa]B activation was enhanced by wild-type I[kappa]B kinase (IKK) [beta] and abolished by the dominant-negative IKK[beta] or a general PKC inhibitor, calphostin C. Importantly, myotrophin-induced expression of two hypertrophic genes (atrial natriuretic factor [ANF] and c-myc) and also enhanced protein synthesis were partially inhibited by a potent NF-[kappa]B inhibitor, pyrrolidine dithio-carbamate (PDTC), and calphostin C. Expression of the dominantnegative form of I[kappa]B-[alpha] or IKK[beta] also partially inhibited the transcriptional activity of ANF induced by myotrophin. These findings suggest that the PKC-IKK-NF-[kappa]B pathway may play a critical role in mediating the myotrophin-induced hypertrophic response in cardiomyocytes.

Author(s): Guilin Tang [1, 2]; Yuzuru Minemoto [1, 2]; Benjamin Dibling [1]; Nicole H. Purcell [1]; Zhiwei Li [3]; Michael Karin [3]; Anning Lin (corresponding author) [1] The proinflammatory cytokine [...]

Two mammalian proteins Rac and Cdc42, controlling the formation of lamellipodia and filopodia, help in the activation of mitogen-activated protein kinase (MAPK), c-Jun N-terminal kinase (JNKs) and p38\Mpk2. JNK and p38 help in the biological functioning of Rac, Cdc42Hs and Dbl in cell growth and proliferation. JNK acts a nucleotide exchange factor for Cdc42Hs in response to Dbl, an oncoprotein. Rac1, intermediate between Ha-Ras and MEKK, helps in signaling cascade.

Byline: Audrey Minden (*), Anning Lin (*), Francois-Xavier Claret (*), Arie Abo (a ), Michael Karin (*) Abstract: The Rho subfamily of GTPases is involved in controlof cell morphology in mammals and yeast. The mammalian Rac and Cdc42 proteins control formation of lamellipodia and filopodia, respectively. These proteins also activate MAP kinase (MAPK) cascades that regulate gene expression. Constitutively activated forms of Rac and Cdc42Hs are efficient activators of a cascade leading to JNK and p38/Mpk2 activation. RhoA did not exhibit this activity, and none of the proteins activated the ERK subgroup of MAPKs. JNK, but not ERK, activation was also observed in response to Dbl, an oncoprotein that acts as a nucleotide exchange factor for Cdc42Hs. Results with dominant interfering alleles place Ract as an intermediate between Ha-Ras and MEKK in the signaling cascade leading from growth factor receptors and v-Src to JNK activation. JNK and p38 activation are likely to contribute to the biological effects of Rac,- Cdc42Hs, and Dbl on cell growth and proliferation. Author Affiliation: (*) Department of Pharmacology Program in Biomedical Science University of California, San Diego School of Medicine La Jolla, California 92093-0636, USA (a ) Onyx Pharmaceuticals 3031 Research Drive Richmond, California 94806, USA

Progenitor cells at the basal layer of skin epidermis play an essential role in maintaining tissue homeostasis and enhancing wound repair in skin. The proliferation, differentiation, and cell death of epidermal progenitor cells have to be delicately regulated, as deregulation of this process can lead to many skin diseases, including skin cancers. However, the underlying molecular mechanisms involved in skin homeostasis remain poorly defined. In this study, with quantitative proteomics approach, we identified an important interaction between KDF1 (keratinocyte differentiation factor 1) and IKKα (IκB kinase α) in differentiating skin keratinocytes. Ablation of either KDF1 or IKKα in mice leads to similar but striking abnormalities in skin development, particularly in skin epidermal differentiation. With biochemical and mouse genetics approach, we further demonstrate that the interaction of IKKα and KDF1 is essential for epidermal differentiation. To probe deeper into the mechanisms, we find that KDF1 associates with a deubiquitinating protease USP7 (ubiquitin‐specific peptidase 7), and KDF1 can regulate skin differentiation through deubiquitination and stabilization of IKKα. Taken together, our study unravels an important molecular mechanism underlying epidermal differentiation and skin tissue homeostasis. Synopsis: KDF1 (Keratinocyte Differentiation Factor 1) promotes the deubiquitination and stability of IKKα by recruiting USP7 (Ubiquitin Specific Peptidase 7). This interaction is essential for skin epidermal differentiation. IKKα interaction with KDF1 is essential for epidermal differentiation.KDF1associates with USP7, which mediates IKKα deubiquitination and stabilization. [ABSTRACT FROM AUTHOR]

The transcription factor NF-[Kappa]B regulates expression of genes that are involved in inflammation, immune response, viral infection, cell survival, and division. However, the role of NF-[Kappa]B in hypertrophic growth of terminally differentiated cardiomyocytes is unknown. Here we report that NF-[Kappa]B activation is required for hypertrophic growth of cardiomyocytes. In cultured rat primary neonatal ventricular cardiomyocytes, the nuclear translocation of NF-[Kappa]B and its transcriptional activity were stimulated by several hypertrophic agonists, including phenylephrine, endothelin-1, and angiotensin II. The activation of NF-[Kappa]B was inhibited by expression of a 'supersuppressor' I[Kappa]B[Alpha] mutant that is resistant to stimulationinduced degradation and a dominant negative I[Kappa]B kinase (IKK[Beta]) mutant that can no longer be activated by phosphorylation. Furthermore, treatment with phenylephrine induced I[Kappa]B[Alpha] degradation in an IKK-dependent manner, suggesting that NF-[Kappa]B is a downstream target of the hypertrophic agonists. Importantly, expression of the supersuppressor I[Kappa]B[Alpha] mutant or the dominant negative IKK[Beta] mutant blocked the hypertrophic agonist-induced expression of the embryonic gene atrial natriuretic factor and enlargement of cardiomyocytes. Conversely, overexpression of NF-[Kappa]B itself induced atrial natriuretic factor expression and cardiomyocyte enlargement. These findings suggest that NF-[Kappa]B plays a critical role in the hypertrophic growth of cardiomyocytes and may serve as a potential target for the intervention of heart disease.

Purcell, Nicole H., Chenfei Yu, Daoyao He, Jialing Xiang, Nir Paran, Joseph A. DiDonato, Shoji Yamaoka, Yosef Shaul, and Anning Lin. Activation of NF-[Kappa]B by hepatitis B virus X protein through an I[Kappa]B kinase-independent mechanism. Am J Physiol Gastrointest Liver Physiol 280: G669-G677, 2001.--pX, the hepatitis B virus-encoded transcription coactivator, is involved in viral infection in vivo. pX stimulates the activity of several transcription factors including nuclear factor-[Kappa]B (NF-[Kappa]B), but the mechanism of activation is poorly understood. The I[Kappa]B kinase complex (IKK) mediates activation of NF-[Kappa]B in response to various extracellular stimuli, including inflammatory cytokines like tumor necrosis factor and interleukin 1, human T cell lymphoma virus 1 Tax protein, and tumor promoters like phorbol esters. It is not known whether IKK also mediates activation of NF-[Kappa]B by pX. Here we report that IKK was not essential for activation of NF-[Kappa]B by pX. Expression of pX resulted in the degradation of I[Kappa]B[Alpha] in the absence of its phosphorylation at [Ser.sup.32] and [Ser.sup.36] residues. Although pX stimulated the activity of cotransfected IKK-[Beta] when it was overexpressed, it failed to activate endogenous IKK. Furthermore, expression of pX stimulated NF-[Kappa]B nuclear translocation and transcriptional activity in IKK-[Gamma]-null fibroblast 5R cells. Our data indicate that pX stimulates NF-[Kappa]B activity through a mechanism that is dependent on I[Kappa]B[Alpha] degradation but not on IKK activation. nuclear factor-[Kappa]B; inhibitor of nuclear factor-[Kappa]B; X protein of hepatitis B virus