A role for keratin 16 in the regulation of epithelial differentiation and homeostasis in glabrous epidermis

This thesis presents novel insight into the pathophysiology of palmoplantar keratoderma and previously unidentified functions for the type I intermediate filament gene keratin 16 (KRT16 gene; K16 protein). Mutations at the KRT16 locus can cause pachyonychia congenita (PC) or focal non-epidermolytic palmoplantar keratoderma (FNEPPK), each of which entail painful calluses on plantar and/or palmar skin. Krt16 null mice develop footpad lesions that mimic several aspects PC-associated PPK and FNEPPK including hypoactive Keap1/Nrf2 signaling and elevated expression of skin barrier homeostasis genes. This provides a unique opportunity to understand the associated pathophysiology of PPK and devise effective therapies that are currently lacking. The novel insights reported in this thesis were generated utilizing transgenic mouse models, ex vivo culture systems, and cell culture assays. First, transfer of the Krt16 null allele to the FVB/N strain background resulted in mice with a qualitatively similar, quantitatively less severe footpad lesions than their C57Bl/6 counterparts (Zieman and Coulombe 2018), highlighting the importance of genetic background in PC and PPK. Second, keratin 9 (KRT9 gene; K9 protein), the most robustly expressed gene in differentiating keratinocytes of volar epidermis, is markedly downregulated in established lesions of Krt16 null paw skin. Follow-up analyses showed that striking decreases in Krt9 transcript and K9 protein represent the earliest molecular lesion detected so far in Krt16 null paw skin. Given that several effectors of terminal differentiation are misregulated in Krt16 null paw skin, impaired terminal differentiation may be a key driver of pathophysiology beginning at an early stage of PC-associated PPK. Third, loss of Krt6a/Krt6b or Krt16 impacts many aspects of activated keratinocytes in similar and divergent fashions, further underscoring the importance of inducing Krt6a/Krt6b and Krt16 at the wound edge. Fourth, loss of IL-1R- or TLR3-dependent signaling minimally impacts the presentation of footpad lesions in Krt16 null mice, suggesting K16 may not directly interact with either of these pathways in volar epidermis. Finally, K16 is capable of localizing to the nucleus of epithelial cells, implying it may serve a functional role within the nucleus. We conclude that K16 is an important regulator of terminal differentiation and homeostasis in glabrous epidermis

Perceptions and predictors of respectful maternity care in Malawi: A quantitative cross-sectional analysis

Objective: Access to high-quality, respectful care is a basic human right. A lack of respectful care during childbirth is associated with poor outcomes and can negatively influence care-seeking and maternal mental health. We aimed to describe how women perceive their experience of maternity care in Malawi. Methods: We implemented a cross-sectional survey of women (n = 660) who delivered in 25 birth facilities in four districts in Malawi in March 2020 using a validated 30-item, 90-point person-centered maternity care (PCMC) scale. We used descriptive statistics to examine women\u27s experience of care and analyzed bivariable and multivariable mixed-effects models to evaluate predictors of PCMC. Statistical models accounted for clustering of women at the facility level and included maternal age, marital status, education, parity, mother or infant complications, timing of antenatal care (ANC), provider cadre and gender, facility type and sector, and district. Results: Mean PCMC score was 57.5 (range 21–84), with the lowest score (12.4 of 27 points) in communication and autonomy. Women reported: being prohibited from having a birth companion during labor (49.4%) or delivery (60.3%); providers did not introduce themselves (81.1%); providers did not ask consent before procedures/examinations (42.4%); women felt they could not ask questions (40.9%); and were not involved in care decisions (61.5%). Few women reported being frequently abused physically (2%) or verbally (3.5%); almost all had water/electricity available ( \u3e 95%). In bivariate analyses, statistically significant positive associations were found between PCMC score and early ANC, male accompaniment to the facility, male provider, and a lack of complications; all associations remained at least potentially statistically significant in multivariable modeling. Conclusions: Physical and verbal abuse and a lack of basic amenities were rare, while a lack of communication with patients and social support were common. Maternal characteristics (like timing of ANC and maternal or newborn complications) were predictors of RMC, while facility/system factors, like facility type and sector, were not. Continued efforts to improve respectful care will require strengthening provider communication skills and encouraging patient and companion involvement in care

Modeling pathways to describe how maternal health care providers’ mental health influences the provision of respectful maternity care in Malawi

Introduction: Maternal health (MH) providers may experience traumatic events, such as maternal or fetal death, that can contribute to stress and burnout. Past trauma, poor working relationships, and under-resourced environments not only affect providers’ own emotional well-being but also reduce their ability to provide respectful maternity care (RMC). Methods: Data were collected in mid-2021 as a cross-sectional survey with 302 MH providers working in 25 maternities in 3 districts in Malawi to measure burnout, depression, and post-traumatic stress disorder (PTSD). We present a pathway model describing how these factors interact and influence RMC. We used the provider-reported person-centered maternity care scale to measure RMC; the Maslach Burnout Inventory, which examines emotional exhaustion, depersonalization, and professional accomplishment; and standard validated screening tools to measure the prevalence of depression and PTSD. Results: Although levels of burnout varied, 30% of MH providers reported high levels of exhaustion, feelings of cynicism manifesting as depersonalization toward their clients (17%), and low levels of professional accomplishment (42%). Moderate to severe depression (9%) and suicidal ideation within the past 2 weeks (10%) were also recorded. Many (70%) reported experiencing an event that could trigger PTSD, and 12% reported at least 4 of 5 symptoms in the PTSD scale. Path analysis suggests that depression and emotional exhaustion negatively influence RMC, and depersonalization is mediated through depression. PTSD has no direct effect on RMC, but increased PTSD scores were associated with increased burnout and depression scores. Positive relationships with facility managers were significantly associated with increased RMC and decreased emotional exhaustion and depersonalization. Conclusion: Burnout will continue to be a challenge among MH providers. However, pragmatic approaches for improving teamwork, psychosocial, and managerial support for MH providers working in challenging environments may help mitigate burnout, improve MH provider well-being, and, in turn, RMC for women seeking MH services

The LINC complex transmits integrin-dependent tension to the nuclear lamina and represses epidermal differentiation

While the mechanisms by which chemical signals control cell fate have been well studied, the impact of mechanical inputs on cell fate decisions is not well understood. Here, using the well-defined system of keratinocyte differentiation in the skin, we examine whether and how direct force transmission to the nucleus regulates epidermal cell fate. Using a molecular biosensor, we find that tension on the nucleus through linker of nucleoskeleton and cytoskeleton (LINC) complexes requires integrin engagement in undifferentiated epidermal stem cells and is released during differentiation concomitant with decreased tension on A-type lamins. LINC complex ablation in mice reveals that LINC complexes are required to repress epidermal differentiation in vivo and in vitro and influence accessibility of epidermal differentiation genes, suggesting that force transduction from engaged integrins to the nucleus plays a role in maintaining keratinocyte progenitors. This work reveals a direct mechanotransduction pathway capable of relaying adhesion-specific signals to regulate cell fate

A role for keratins in supporting mitochondrial organization and function in skin keratinocytes

Mitochondria fulfill essential roles in ATP production, metabolic regulation, calcium signaling, generation of reactive oxygen species (ROS), and additional determinants of cellular health. Recent studies have highlighted a role for mitochondria during cell differentiation, including in skin epidermis. The observation of oxidative stress in keratinocytes from null mouse skin, a model for pachyonychia congenita (PC)-associated palmoplantar keratoderma, prompted us to examine the role of Keratin (K) 16 protein and its partner K6 in regulating the structure and function of mitochondria. Electron microscopy revealed major anomalies in mitochondrial ultrastructure in late stage, E18.5, null embryonic mouse skin. Follow-up studies utilizing biochemical, metabolic, and live imaging readouts showed that, relative to controls, skin keratinocytes null for or exhibit elevated ROS, reduced mitochondrial respiration, intracellular distribution differences, and altered movement of mitochondria within the cell. These findings highlight a novel role for K6 and K16 in regulating mitochondrial morphology, dynamics, and function and shed new light on the causes of oxidative stress observed in PC and related keratin-based skin disorders

Applying a power and gender lens to understanding health care provider experience and behavior: A multicountry qualitative study

A limited but growing body of literature shows that health care providers (HCPs) in reproductive, maternal, and newborn health face challenges that affect how they provide services. Our study investigates provider perspectives and behaviors using 4 interrelated power domains—beliefs and perceptions; practices and participation; access to assets; and structures—to explore how these constructs are differentially experienced based on one’s gender, position, and function within the health system. We conducted a framework-based secondary analysis of qualitative in-depth interview data gathered with different cadres of HCPs across Kenya, Malawi, Madagascar, and Togo (n=123). We find across countries that power dynamics manifest in and are affected by all 4 domains, with some variation by HCP cadre and gender. At the service interface, HCPs’ power derives from the nature and quality of their relationships with clients and the community. Providers’ power within working relationships stems from unequal decision-making autonomy among HCP cadres. Limited and sometimes gendered access to remuneration, development opportunities, material resources, supervision quality, and emotional support affect HCPs’ power to care for clients effectively. Power manifests variably among community and facility-based providers because of differences in prevailing hierarchical norms in routine and acute settings, community linkages, and type of collaboration required in their work. Our findings suggest that applying power—and secondarily, gender lenses—can elucidate consistencies in how providers perceive, internalize, and react to a range of relational and environmental stressors. The findings also have implications on how to improve the design of social behavior change interventions aimed at better supporting HCPs