Advancing precision psychiatry and targeted treatments: Insights from immunopsychiatry.

Despite tremendous advancements in neuroscience, there has been limited impact on patient care. Current psychiatric treatments are largely non-specific, and drug development is hindered by outdated, overinclusive diagnostic categories and a "one-size-fits-all" approach. Additionally, mechanisms underlying psychiatric illnesses and their treatments with conventional medications remain poorly understood.

Evidence for a granule targeting sequence within platelet factor 4.

Platelets achieve bleeding arrest at sites of vascular injury via secretion of secretory proteins from their storage granules, termed alpha-granules. We have recently analyzed granule targeting of platelet factor 4 (PF4), a secretory alpha-granule chemokine, and demonstrated that PF4 alpha-granule storage relied upon determinants within PF4 mature sequence. To define these determinants, PF4 mutants fused to the fluorescent reporter protein green fluorescent protein were generated by progressive deletions and site-directed mutagenesis.

Probing platelet factor 4 alpha-granule targeting.

The storage mechanism of endogenous secretory proteins in megakaryocyte alpha-granules is poorly understood. We have elected to study the granule storage of platelet factor 4 (PF4), a well-known platelet alpha-granule protein. The reporter protein green fluorescent protein (GFP), PF4, or PF4 fused to GFP (PF4-GFP), were transfected in the well-characterized mouse pituitary AtT20 cell line, and in the megakaryocytic leukemic DAMI cell line.

Thrombopoietin-induced Dami cells as a model for alpha-granule biogenesis.

Megakaryocytic alpha-granules contain secretory proteins relevant to megakaryocyte and platelet functions. Understanding alpha-granule biogenesis is hampered because human primary megakaryocytes are difficult to manipulate. Existing promegakaryocytic cell lines do not spontaneously exhibit mature alpha-granules.

cld and lec23 are disparate mutations that affect maturation of lipoprotein lipase in the endoplasmic reticulum.

The mutations cld (combined lipase deficiency) and lec23 disrupt in a similar manner the expression of lipoprotein lipase (LPL). Whereas cld affects an unknown gene, lec23 abolishes the activity of alpha-glucosidase I, an enzyme essential for proper folding and assembly of nascent glycoproteins. The hypothesis that cld, like lec23, affects the folding/assembly of nascent LPL was confirmed by showing that in cell lines homozygous for these mutations (Cld and Lec23, respectively), the majority of LPL was inactive, displayed heterogeneous aggregation, and had a decreased affinity for heparin.

Enhanced detection of lipoprotein lipase by combining immunoprecipitation with Western blot analysis.

This manuscript describes the problems inherent in combining immunoprecipitation of lipoprotein lipase (LPL) with its detection by Western blot, and how these problems can be circumvented by the preparation of suitable immunoreagents. These reagents used during the immunoprecipitation step, include Fab fragments of the primary antibody (chicken anti-bovine LPL), and a covalently linked immunomatrix of the secondary antibody (rabbit anti-chicken IgG). The use of these reagents in conjunction with Western blot detection virtually eliminates the problem of non-relevant protein detection when analyzing LPL from complex biological samples.

Evidence for a sustained genetic effect on fat storage capacity in cultured adipose cells from Zucker rats.

Using mature adipocytes and preadipocytes from genetically obese Zucker rats, we investigated the cells' ability to maintain abnormal fat storage capacity when withdrawn from their in vivo environment. Long-term adipocyte cultures from obese rats displayed an increase in both glucose consumption (GC) and enzyme activities, including fatty acid synthase (4-fold), glycerol-3-phosphate dehydrogenase (4.5-fold), lipoprotein lipase (LPL; 6-fold), and malic enzyme (2.