Publications

Chromatin immunoprecipitations in naive CD4, but not CD8, T cells, demonstrated association of the IL-4 promoter with acetylated histone. Histone modifications and rapid IL-4 transcription were absent in conserved noncoding sequence 1 (CNS-1)(-/-) cells lacking an 8-kb-distant enhancer in the IL-4/IL-13 intergenic region, but also in CD4(-/-) and Itk(-/-) cells, which have similar Th2 deficiencies. Histones associated with the IL-13 promoter were not similarly acetylated in naive T cells, but became acetylated in differentiated Th2 cells. Conversely, Th1 differentiation induced histone methylation at the type 2 cytokine locus. Like CD4(-/-) and Itk(-/-) mice, CNS-1(-/-) BALB/c mice were highly resistant to the Th2-inducing protozoan, Leishmania major. CNS-1 deficiency led to failure of IL-4 gene repositioning to heterochromatin after Th1 polarization, possibly related to the presence of reiterative Ikaros binding sites in the intergenic element. Hyperacetylation of nonexpressed genes may serve to mark lineage-specific loci for rapid expression and further modification.

OBJECTIVE

To estimate the incidence of lipoatrophy and lipohypertrophy among HIV-infected and HIV-uninfected women from the Women's Interagency HIV Study.

DESIGN

Eight hundred fifteen women with semiannual data on self-report of bidirectional change in body fat, anthropometric measurements, weight, and bioelectric impedance analysis were included in a 30-month incidence analysis.

METHODS

Lipoatrophy and lipohypertrophy in both peripheral (arms, legs, and buttocks) and central (waist, chest, and upper back) sites were defined by self-report of either a decrease or an increase in a body fat region over the previous 6 months that was confirmed by a corresponding change in anthropometric measurement.

RESULTS

Weight and total body fat increased in HIV-uninfected women but remained stable in HIV-infected women over 30 months. Among HIV-infected women, the incidence of peripheral (relative hazard, 2.1; 95% confidence interval [CI], 1.4-3.3) and central (relative hazard, 1.9; 95% CI, 1.2-2.8) lipoatrophy was about double that among HIV-uninfected women, after adjustment for age and race. The incidence of peripheral lipohypertrophy appeared lower among HIV-infected women than among HIV-uninfected women (relative hazard, 0.8; 95% CI, 0.6-1.1), while the incidence of central lipohypertrophy did not differ by HIV status. Of HIV-infected women with 2 of 4 lipodystrophy outcomes, most (81%) had combined peripheral and central lipoatrophy or combined peripheral and central lipohypertrophy. Only 14% of these women had both peripheral lipoatrophy and central lipohypertrophy.

CONCLUSIONS

These prospective data suggest that lipoatrophy, affecting both peripheral and central sites, predominates in HIV-infected women. The simultaneous occurrence of peripheral lipoatrophy and central lipohypertrophy was uncommon.

By homology to triggering receptor expressed by myeloid cells-2, we screened the mouse expressed sequence tag database and isolated a new single Ig domain receptor, which we have expressed and characterized. The receptor is most similar in sequence to the human CMRF-35 receptor, and thus we have named it CMRF-35-like molecule (CLM)-1. By screening the mouse genome, we determined that CLM-1 was part of a multigene family located on a small segment of mouse chromosome 11. Each contains a single Ig domain, and they are expressed mainly in cells of the myeloid lineage. CLM-1 contains multiple cytoplasmic tyrosine residues, including two that lie in consensus immunoreceptor tyrosine-based inhibitory motifs, and we demonstrate that CLM-1 can associate with Src-homology 2 containing phosphatase-1. Expression of CLM-1 mRNA is down-regulated by treatment with receptor activator of NF-kappaB ligand (RANKL), a cytokine that drives osteoclast formation. Furthermore, expression of CLM-1 in the osteoclastogenic cell line RAW (RAW.CLM-1) prevents osteoclastogenesis induced by RANKL and TGF-beta. RAW.CLM-1 cells fail to multinucleate and do not up-regulate calcitonin receptor, but they express tartrate-resistant acid phosphatase, cathepsin K, and beta(3) integrin, suggesting that osteoclastogenesis is blocked at a late-intermediate stage. Thus, we define a new family of myeloid receptors, and demonstrate that the first member of this family, CLM-1, is an inhibitory receptor, able to block osteoclastogenesis.

Gag-specific CD4 proliferative responses correlate inversely with HIV-1 RNA levels in infected adults, and robust responses are characteristic of long-term nonprogressive infection. However, strong responses are seldom detected in adult subjects with progressive infection and are not generally reconstituted on highly active antiretroviral therapy (HAART). To date, the role of HIV-1-specific Th responses in children has not been thoroughly examined. We characterized Gag-specific CD4 responses among 35 perinatally infected subjects, including 2 children who spontaneously control viremia without antiretroviral therapy, 21 children with viral loads (VL) of <400 on HAART, and 12 viremic children. Gag-specific Th activity was assessed by lymphoproliferative assay, and responses were mapped using overlapping Gag peptides in an IFN-gamma ELISPOT. Robust proliferative responses were detected in the children exhibiting spontaneous control of viremia, and mapping of targeted Gag regions in one such subject identified multiple epitopes. Among children >or=5 years old, 14 of 17 subjects with VL of <400 on HAART demonstrated a significant p24 proliferative response (median p24 stimulation index, 20), in contrast with only 1 of 9 viremic children (median p24 stimulation index, 2.0; p = 0.0008). However, no subject younger than 5 years of age possessed a significant response, even when viremia was fully suppressed. When compared with adults with VL of <400 on HAART, Th responses among children with VL of <400 were both more frequent (p = 0.009) and of greater magnitude (p = 0.002). These data suggest that children may have a greater intrinsic capacity to reconstitute HIV-1-specific immunity than adults, and may be excellent candidates for immune-based therapies.

Vacuolar H(+)-ATPases (V-ATPases) are a family of highly conserved proton pumps that couple hydrolysis of cytosolic ATP to proton transport out of the cytosol. How ATP is supplied for V-ATPase-mediated hydrolysis and for coupling of proton transport is poorly understood. We have reported that the glycolytic enzyme aldolase physically associates with V-ATPase. Here we show that aldolase interacts with three different subunits of V-ATPase (subunits a, B, and E). The binding sites for the V-ATPase subunits on aldolase appear to be on distinct interfaces of the glycolytic enzyme. Aldolase deletion mutant cells were able to grow in medium buffered at pH 5.5 but not at pH 7.5, displaying a growth phenotype similar to that observed in V-ATPase subunit deletion mutants. Abnormalities in V-ATPase assembly and protein expression observed in aldolase deletion mutant cells could be fully rescued by aldolase complementation. The interaction between aldolase and V-ATPase increased dramatically in the presence of glucose, suggesting that aldolase may act as a glucose sensor for V-ATPase regulation. Taken together, these findings provide functional evidence that the ATP-generating glycolytic pathway is directly coupled to the ATP-hydrolyzing proton pump through physical interaction between aldolase and V-ATPase.