title: Myostatin signals through Pax7 to regulate satellite cell self-renewal

authors: McFarlane, Craig Desmond

subjects: Myostatin

abstract: Myostatin, a Transforming Growth Factor-beta (TGF-β) super-family member, has previously been shown to negatively regulate satellite cell activation and self-renewal. However, to date the mechanism behind Myostatin function in satellite cell biology is not known. Here we show that Myostatin signals via a Pax7-dependent mechanism to regulate satellite cell self-renewal. While excess Myostatin inhibited Pax7 expression via ERK1/2 signaling, an increase in Pax7 expression was observed following both genetic inactivation and functional antagonism of Myostatin. As a result, we show that either blocking or inactivating Myostatin enhances the partitioning of the fusion-incompetent self-renewed satellite cell lineage (high Pax7 expression, low MyoD expression) from the pool of actively proliferating myogenic precursor cells. Consistent with this result, over-expression of Pax7 in C2C12 myogenic cells resulted in increased self-renewal through a mechanism which slowed both myogenic proliferation and differentiation. Taken together, these results suggest that increased expression of Pax7 promotes satellite cell self-renewal, and furthermore Myostatin may control the process of satellite cell self-renewal through regulation of Pax7. Thus we speculate that, in addition to the intrinsic factors (such as Pax7), extrinsic factors both positive and negative in nature, will play a major role in determining the stemness of skeletal muscle satellite cells.

text: Myostatin signals through Pax7 to regulate satellite cell self-renewal Myostatin, a Transforming Growth Factor-beta (TGF-β) super-family member, has previously been shown to negatively regulate satellite cell activation and self-renewal. However, to date the mechanism behind Myostatin function in satellite cell biology is not known. Here we show that Myostatin signals via a Pax7-dependent mechanism to regulate satellite cell self-renewal. While excess Myostatin inhibited Pax7 expression via ERK1/2 signaling, an increase in Pax7 expression was observed following both genetic inactivation and functional antagonism of Myostatin. As a result, we show that either blocking or inactivating Myostatin enhances the partitioning of the fusion-incompetent self-renewed satellite cell lineage (high Pax7 expression, low MyoD expression) from the pool of actively proliferating myogenic precursor cells. Consistent with this result, over-expression of Pax7 in C2C12 myogenic cells resulted in increased self-renewal through a mechanism which slowed both myogenic proliferation and differentiation. Taken together, these results suggest that increased expression of Pax7 promotes satellite cell self-renewal, and furthermore Myostatin may control the process of satellite cell self-renewal through regulation of Pax7. Thus we speculate that, in addition to the intrinsic factors (such as Pax7), extrinsic factors both positive and negative in nature, will play a major role in determining the stemness of skeletal muscle satellite cells.

year: 2008

title: Heritage buildings and community sense of place

authors: Boston, Megan

abstract: New Zealand is a nation that has a significant amount of built heritage, of which there are several internationally recognised landmarks, including the Christchurch Cathedral, the Church of the Good Shepherd, and the Chateau Tongariro. These structures contribute to establishing a sense of place within a community as landmarks, gathering places, and keepers of memories and personal sentiments. Unfortunately, due to New Zealand’s recent and historic seismic activity, these landmarks, commonly constructed as unreinforced concrete or masonry, are susceptible to severe damage from earthquake-induced ground shaking. For this reason, the New Zealand government introduced the Building (Earthquake-prone Buildings) Amendment Act 2016, which presented stricter seismic strengthening regulations for vulnerable buildings (earthquake-prone buildings) to ensure better life safety outcomes for such structures. The associated costs and challenges of retrofitting heritage buildings have put many of these structures at risk of abandonment or demolition, taking their embodied heritage value with them. This research uses survey data to establish how heritage buildings develop a sense of place within a community and how the public’s perception can implicate preserving heritage buildings. Survey results indicated that people value these structures in their communities. Further, personal connections to heritage buildings or knowledge of the historical context improve the desire to preserve and restore these structures.

text: Heritage buildings and community sense of place New Zealand is a nation that has a significant amount of built heritage, of which there are several internationally recognised landmarks, including the Christchurch Cathedral, the Church of the Good Shepherd, and the Chateau Tongariro. These structures contribute to establishing a sense of place within a community as landmarks, gathering places, and keepers of memories and personal sentiments. Unfortunately, due to New Zealand’s recent and historic seismic activity, these landmarks, commonly constructed as unreinforced concrete or masonry, are susceptible to severe damage from earthquake-induced ground shaking. For this reason, the New Zealand government introduced the Building (Earthquake-prone Buildings) Amendment Act 2016, which presented stricter seismic strengthening regulations for vulnerable buildings (earthquake-prone buildings) to ensure better life safety outcomes for such structures. The associated costs and challenges of retrofitting heritage buildings have put many of these structures at risk of abandonment or demolition, taking their embodied heritage value with them. This research uses survey data to establish how heritage buildings develop a sense of place within a community and how the public’s perception can implicate preserving heritage buildings. Survey results indicated that people value these structures in their communities. Further, personal connections to heritage buildings or knowledge of the historical context improve the desire to preserve and restore these structures.

year: 2024

title: Culture – the foundation of Maori Governance

authors: Toki, Valmaine

abstract: The structure of a governance system specifies the distribution of rights and responsibilities among different participants dictating the mutually agreed rules and procedures for making decisions on business affairs. For Maori, an indigenous people, the unique and pivotal factor that provides the point of difference, for governance, is the importance of their culture. Notwithstanding this point of difference, there exists a paucity of governance structures that adequately cater and provide for culture.

text: Culture – the foundation of Maori Governance The structure of a governance system specifies the distribution of rights and responsibilities among different participants dictating the mutually agreed rules and procedures for making decisions on business affairs. For Maori, an indigenous people, the unique and pivotal factor that provides the point of difference, for governance, is the importance of their culture. Notwithstanding this point of difference, there exists a paucity of governance structures that adequately cater and provide for culture.

year: 2013