Lloyd White | La Trobe University (original) (raw)

Papers by Lloyd White

Anatomical Sciences Education, 2015

Benefits of collaborative testing have been identified in many disciplines. This study sought to ... more Benefits of collaborative testing have been identified in many disciplines. This study sought to determine whether collaborative practical tests encouraged active learning of anatomy. A gross anatomy course included a collaborative component in four practical tests. Two hundred and seven students initially completed the test as individuals and then worked as a team to complete the same test again immediately afterwards. The relationship between mean individual, team, and difference (between team and individual) test scores to overall performance on the final examination (representing overall learning in the course) was examined using regression analysis. The overall mark in the course increased by 9% with a decreased failure rate. There was a strong relationship between individual score and final examination mark (P < 0.001) but no relationship for team score (P = 0.095). A longitudinal analysis showed that the test difference scores increased after Test 1 which may be indicative of social loafing and this was confirmed by a significant negative relationship between difference score on Test 4 (indicating a weaker student) and final examination mark (P < 0.001). It appeared that for this cohort, there was little peer-to-peer learning occurring during the collaborative testing and that weaker students gained the benefit from team marks without significant active learning taking place. This negative outcome may be due to insufficient encouragement of the active learning strategies that were expected to occur during the collaborative testing process. An improved understanding of the efficacy of collaborative assessment could be achieved through the inclusion of questionnaire based data to allow a better interpretation of learning outcomes. Anat Sci Educ. © 2015 American Association of Anatomists.

Reproduction, Fertility and Development, 2008

The Journal of biological chemistry, 2011

MicroRNAs (miRs) are emerging as prominent players in the regulation of many biological processes... more MicroRNAs (miRs) are emerging as prominent players in the regulation of many biological processes, including myogenic commitment and skeletal muscle formation. Members of the TGF-␤ family can influence the proliferation and myogenic differentiation of cells, although it is presently not clear what role miRNAs play in the TGF-␤-mediated control of myogenic differentiation. Here, we demonstrate in the myogenic C2C12 cell line, and in primary muscle cells, that miR-206 and miR-29-two miRs that act on transcriptional events implicated in muscle differentiation are down-regulated by TGF-␤. We further demonstrate that TGF-␤ treatment of myogenic cells is associated with increased expression of histone deacetylase 4 (HDAC4), a key inhibitor of muscle differentiation that has been identified as a target for regulation by miR-206 and miR-29. We confirmed that increased expression of miR-206 and miR-29 resulted in the translational repression of HDAC4 in the presence or absence of TGF-␤ via interaction with the HDAC4 3-untranslated region. Importantly, we found that miR-206 and miR-29 can attenuate the inhibitory actions of TGF-␤ on myogenic differentiation. Furthermore, we present evidence that the mechanism by which miR-206 and miR-29 can inhibit the TGF-␤-mediated up-regulation of HDAC4 is via the inhibition of Smad3 expression, a transducer of TGF-␤ signaling. These findings identify a novel mechanism of interaction between TGF-␤ and miR-206 and -29 in the regulation of myogenic differentiation through HDAC4. . The abbreviations used are: MRF, muscle regulatory factor; miR, microRNA; HDAC, histone deacetylase; NC, negative control.

Reproductive Biomedicine Online, 2009

Secreted frizzled-related protein 4 (sFRP4) blocks the Wnt signalling pathway by competitively bi... more Secreted frizzled-related protein 4 (sFRP4) blocks the Wnt signalling pathway by competitively binding Wnt ligands (frizzled receptors). This pathway is important during development and oncogenesis. It is, however, complex with a large number of interacting proteins, isoforms and receptors. The Wnt signalling pathway has a role in human placental development and implantation, particularly in the trophoblast. Humans and macaque monkeys exhibit a similar remodelling of the decidual spiral arteries. The expression of sFRP4 in human and macaque placentas at different gestational ages have been examined with immunohistochemistry, in-situ hybridization, real-time polymerase chain reaction, and Western blotting. This study demonstrates that sFRP4 is expressed predominantly in the villous syncytiotrophoblast and the invasive intermediate cytotrophoblast, and in the amnion. These observational studies suggest that sFRP4 has a role in placental development and implantation, and may be an important factor in the development of the decidual fibrinoid zone, and in trophoblast apoptosis and a band of apoptosis in the underlying decidua deep into the trophoblast.

Reproductive Biology and Endocrinology, 2009

Background: Within the human placenta, the cytotrophoblast consists of a proliferative pool of pr... more Background: Within the human placenta, the cytotrophoblast consists of a proliferative pool of progenitor cells which differentiate to replenish the overlying continuous, multi-nucleated syncytiotrophoblast, which forms the barrier between the maternal and fetal tissues. Disruption to trophoblast differentiation and function may result in impaired fetal development and preeclampsia. Caspase-14 expression is limited to barrier forming tissues. It promotes keratinocyte differentiation by cleaving profilaggrin to stabilise keratin intermediate filaments, and indirectly providing hydration and UV protection. However its role in the trophoblast remains unexplored.

Reproductive Biomedicine Online, 2007

The human placenta is responsible for the exchange of nutrients, gas and wastes through the troph... more The human placenta is responsible for the exchange of nutrients, gas and wastes through the trophoblast maternal−fetal barrier, which is formed by the fusion of villous cytotrophoblasts to form the continuous multinucleated syncytiotrophoblast separating the maternal and fetal circulations. Caspase-14 is a seemingly non-apoptotic caspase involved in keratinocyte differentiation and cornification. It is proposed that caspase-14 has a conserved role in cellular differentiation and a role in differentiation and fusion in the trophoblast. The human choriocarcinoma BeWo cell line was treated with staurosporine and forskolin to induce apoptosis and differentiation respectively. Staurosporine initiated apoptosis within 3 h of treatment, while apoptosis was completed following 6 h treatment. Caspase-14 gene and protein expression was unchanged throughout this process. During BeWo differentiation, caspase-14 mRNA was elevated after 48 h forskolin treatment, while its protein was increased after 24 h. Therefore, caspase-14 is upregulated during trophoblast differentiation, as represented by the BeWo cell line. Moreover, caspase-14 may interact with other signalling molecules to facilitate differentiation. This new data confirms the potential for the BeWo cell line in the functional dissection of this unusual caspase and its prospective role in trophoblast differentiation.

Pflugers Archiv-european Journal of Physiology, 2011

Skeletal muscle atrophy occurs in many chronic diseases and disuse conditions. Its severity reduc... more Skeletal muscle atrophy occurs in many chronic diseases and disuse conditions. Its severity reduces patient recovery, independence and quality of life. The discovery of two muscle-specific E3 ubiquitin ligases, MAFbx/atrogin-1 and Muscle RING Finger-1 (MuRF1), promoted an expectation of these molecules as targets for therapeutic development. While numerous studies have determined the conditions in which MAFbx/atrogin-1 and MuRF1 mRNA levels are regulated, few studies have investigated their functional role in skeletal muscle. Recently, studies identifying new target substrates for MAFbx/atrogin-1 and MuRF1, outside of their response to the initiation of muscle atrophy, suggest that there is more to these proteins than previously appreciated. This review will highlight our present knowledge of MAFbx/atrogin-1 and MuRF1 in skeletal muscle atrophy, the impact of potential therapeutics and their known regulators and substrates. Finally, we will comment on new approaches that may expand our knowledge of these two molecules in their control of skeletal muscle function.

Anatomical Sciences Education, 2015

Benefits of collaborative testing have been identified in many disciplines. This study sought to ... more Benefits of collaborative testing have been identified in many disciplines. This study sought to determine whether collaborative practical tests encouraged active learning of anatomy. A gross anatomy course included a collaborative component in four practical tests. Two hundred and seven students initially completed the test as individuals and then worked as a team to complete the same test again immediately afterwards. The relationship between mean individual, team, and difference (between team and individual) test scores to overall performance on the final examination (representing overall learning in the course) was examined using regression analysis. The overall mark in the course increased by 9% with a decreased failure rate. There was a strong relationship between individual score and final examination mark (P < 0.001) but no relationship for team score (P = 0.095). A longitudinal analysis showed that the test difference scores increased after Test 1 which may be indicative of social loafing and this was confirmed by a significant negative relationship between difference score on Test 4 (indicating a weaker student) and final examination mark (P < 0.001). It appeared that for this cohort, there was little peer-to-peer learning occurring during the collaborative testing and that weaker students gained the benefit from team marks without significant active learning taking place. This negative outcome may be due to insufficient encouragement of the active learning strategies that were expected to occur during the collaborative testing process. An improved understanding of the efficacy of collaborative assessment could be achieved through the inclusion of questionnaire based data to allow a better interpretation of learning outcomes. Anat Sci Educ. © 2015 American Association of Anatomists.

Reproduction, Fertility and Development, 2008

The Journal of biological chemistry, 2011

MicroRNAs (miRs) are emerging as prominent players in the regulation of many biological processes... more MicroRNAs (miRs) are emerging as prominent players in the regulation of many biological processes, including myogenic commitment and skeletal muscle formation. Members of the TGF-␤ family can influence the proliferation and myogenic differentiation of cells, although it is presently not clear what role miRNAs play in the TGF-␤-mediated control of myogenic differentiation. Here, we demonstrate in the myogenic C2C12 cell line, and in primary muscle cells, that miR-206 and miR-29-two miRs that act on transcriptional events implicated in muscle differentiation are down-regulated by TGF-␤. We further demonstrate that TGF-␤ treatment of myogenic cells is associated with increased expression of histone deacetylase 4 (HDAC4), a key inhibitor of muscle differentiation that has been identified as a target for regulation by miR-206 and miR-29. We confirmed that increased expression of miR-206 and miR-29 resulted in the translational repression of HDAC4 in the presence or absence of TGF-␤ via interaction with the HDAC4 3-untranslated region. Importantly, we found that miR-206 and miR-29 can attenuate the inhibitory actions of TGF-␤ on myogenic differentiation. Furthermore, we present evidence that the mechanism by which miR-206 and miR-29 can inhibit the TGF-␤-mediated up-regulation of HDAC4 is via the inhibition of Smad3 expression, a transducer of TGF-␤ signaling. These findings identify a novel mechanism of interaction between TGF-␤ and miR-206 and -29 in the regulation of myogenic differentiation through HDAC4. . The abbreviations used are: MRF, muscle regulatory factor; miR, microRNA; HDAC, histone deacetylase; NC, negative control.

Reproductive Biomedicine Online, 2009

Secreted frizzled-related protein 4 (sFRP4) blocks the Wnt signalling pathway by competitively bi... more Secreted frizzled-related protein 4 (sFRP4) blocks the Wnt signalling pathway by competitively binding Wnt ligands (frizzled receptors). This pathway is important during development and oncogenesis. It is, however, complex with a large number of interacting proteins, isoforms and receptors. The Wnt signalling pathway has a role in human placental development and implantation, particularly in the trophoblast. Humans and macaque monkeys exhibit a similar remodelling of the decidual spiral arteries. The expression of sFRP4 in human and macaque placentas at different gestational ages have been examined with immunohistochemistry, in-situ hybridization, real-time polymerase chain reaction, and Western blotting. This study demonstrates that sFRP4 is expressed predominantly in the villous syncytiotrophoblast and the invasive intermediate cytotrophoblast, and in the amnion. These observational studies suggest that sFRP4 has a role in placental development and implantation, and may be an important factor in the development of the decidual fibrinoid zone, and in trophoblast apoptosis and a band of apoptosis in the underlying decidua deep into the trophoblast.

Reproductive Biology and Endocrinology, 2009

Background: Within the human placenta, the cytotrophoblast consists of a proliferative pool of pr... more Background: Within the human placenta, the cytotrophoblast consists of a proliferative pool of progenitor cells which differentiate to replenish the overlying continuous, multi-nucleated syncytiotrophoblast, which forms the barrier between the maternal and fetal tissues. Disruption to trophoblast differentiation and function may result in impaired fetal development and preeclampsia. Caspase-14 expression is limited to barrier forming tissues. It promotes keratinocyte differentiation by cleaving profilaggrin to stabilise keratin intermediate filaments, and indirectly providing hydration and UV protection. However its role in the trophoblast remains unexplored.

Reproductive Biomedicine Online, 2007

The human placenta is responsible for the exchange of nutrients, gas and wastes through the troph... more The human placenta is responsible for the exchange of nutrients, gas and wastes through the trophoblast maternal−fetal barrier, which is formed by the fusion of villous cytotrophoblasts to form the continuous multinucleated syncytiotrophoblast separating the maternal and fetal circulations. Caspase-14 is a seemingly non-apoptotic caspase involved in keratinocyte differentiation and cornification. It is proposed that caspase-14 has a conserved role in cellular differentiation and a role in differentiation and fusion in the trophoblast. The human choriocarcinoma BeWo cell line was treated with staurosporine and forskolin to induce apoptosis and differentiation respectively. Staurosporine initiated apoptosis within 3 h of treatment, while apoptosis was completed following 6 h treatment. Caspase-14 gene and protein expression was unchanged throughout this process. During BeWo differentiation, caspase-14 mRNA was elevated after 48 h forskolin treatment, while its protein was increased after 24 h. Therefore, caspase-14 is upregulated during trophoblast differentiation, as represented by the BeWo cell line. Moreover, caspase-14 may interact with other signalling molecules to facilitate differentiation. This new data confirms the potential for the BeWo cell line in the functional dissection of this unusual caspase and its prospective role in trophoblast differentiation.

Pflugers Archiv-european Journal of Physiology, 2011

Skeletal muscle atrophy occurs in many chronic diseases and disuse conditions. Its severity reduc... more Skeletal muscle atrophy occurs in many chronic diseases and disuse conditions. Its severity reduces patient recovery, independence and quality of life. The discovery of two muscle-specific E3 ubiquitin ligases, MAFbx/atrogin-1 and Muscle RING Finger-1 (MuRF1), promoted an expectation of these molecules as targets for therapeutic development. While numerous studies have determined the conditions in which MAFbx/atrogin-1 and MuRF1 mRNA levels are regulated, few studies have investigated their functional role in skeletal muscle. Recently, studies identifying new target substrates for MAFbx/atrogin-1 and MuRF1, outside of their response to the initiation of muscle atrophy, suggest that there is more to these proteins than previously appreciated. This review will highlight our present knowledge of MAFbx/atrogin-1 and MuRF1 in skeletal muscle atrophy, the impact of potential therapeutics and their known regulators and substrates. Finally, we will comment on new approaches that may expand our knowledge of these two molecules in their control of skeletal muscle function.